Fault, warning and safety-shutdown messages documented by Johnson Controls for the YORK YCAV. Each row cites the page of the manual it was taken from — nothing here is summarised or reworded.
From YCAV0157, YCAV0177, YCAV0187, YCAV0197, YCAV0207, YCAV0227, YCAV0247, YCAV0267 Style A 60 Hz Installation, Operation and Maintenance 201.21-NM1
Original: docs.johnsoncontrols.com
VSD safeties (faults)
| Code / display | Meaning | Cause | Action | Page |
|---|---|---|---|---|
| UNIT YYYYYYYY PRECHARGE - LOW DC BUS VOLTAGE 4-compressor units: SYS X YYYYYYYY PRECHARGE - LOW DC BUS VOLT | Software fault. Unit fault on 2- and 3-compressor chillers; system fault (Sys 1/3 or 2/4) on 4-compressor chillers. | The DC bus voltage must reach at least 50 VDC within four seconds and 500 VDC within 19 seconds after the pre-charge signal has been asserted. If not, the unit/system will shut down on a fault. | Auto-restart safety: restarts when the fault clears; locks out on the 3rd fault in 90 minutes. A lockout will not restart until the operator clears the fault using the keypad. | 209 |
| UNIT YYYYYYYY PRECHARGE - DC BUS VOLTAGE IMBALANCE 4-compressor units: SYS X YYYYYYYY PRECHARGE-BUS VOLT IMBAL | Software fault. Unit fault on 2- and 3-compressor chillers; system 1/3 or 2/4 fault on 4-compressor chillers. Locks out on the 1st fault. | The 1/2 DC bus voltage magnitude must remain within +/- 100 VDC of the total DC bus voltage divided by two during the pre-charge interval. If not, the unit/system shall shut down on a fault. | Locks out on the 1st fault; will not restart until the operator clears the fault using the keypad. | 209 |
| UNIT YYYYYYYY HIGH DC BUS VOLTAGE 4-compressor units: SYS X YYYYYYYY HIGH DC BUS VOLTAGE | Hardware fault. Unit fault on 2- and 3-compressor chillers; system 1/3 or 2/4 fault on 4-compressor chillers. Immediate shutdown. | The high DC bus voltage trip level is determined by hardware on the VSD Logic Board and is designed to trip the unit at 766 +/- 30 VDC. If the DC bus exceeds this level, the unit/system will fault and shut down immediately. | Auto-restart safety: restarts when the fault clears; locks out on the 3rd fault in 90 minutes. A lockout will not restart until the operator clears the fault using the keypad. | 209 |
| UNIT YYYYYYYY LOW DC BUS VOLTAGE 4-compressor units: SYS X YYYYYYYY LOW DC BUS VOLTAGE | Software fault. Unit fault on 2- and 3-compressor chillers; system fault (1/3 or 2/4) on 4-compressor chillers. Immediate shutdown. | The low DC bus voltage trip level is set at 500 VDC. If the DC bus drops below this level the unit/system will fault and immediately shut down. | Auto-restart safety: locks out on the 3rd fault in 90 minutes. A lockout will not restart until the operator clears the fault using the keypad. | 210 |
| UNIT YYYYYYYY DC BUS VOLTAGE IMBALANCE 4-compressor units: SYS X YYYYYYYY DC BUS VOLTAGE IMBALANCE | Software fault. Unit fault on 2- and 3-compressor chillers; system 1/3 or 2/4 fault on 4-compressor chillers. Locks out on the 1st fault. | The 1/2 DC bus voltage magnitude must remain within +/- 100 VDC of the total DC bus voltage divided by two. If the 1/2 DC bus magnitude exceeds the +/- 100 VDC tolerances, the unit/system will fault and immediately shut down. | Locks out on the 1st fault; will not restart until the operator clears the fault using the keypad. | 210 |
| SYS X YYYYYYYY HIGH MOTOR CURRENT | Hardware fault; individual system/compressor fault for all units. Immediate shutdown. | The three output lines to each phase of the compressor motor are monitored via three current transformers within the VSD and instantaneous output current is compared to a predetermined hardware limit. Nominal peak current trip level is 575.5 Amps (554A min., 597A max.); 380V AC 60 Hz and 400V AC 50 Hz nominal peak current trip level is 649.5 Amps (626 Amps min., 674 Amps max.). The variation in trip point is the result of component tolerances on the VSD Logic Board. If the peak current limit is exceeded, the unit will fault and shut down immediately. | Auto-restart safety: locks out the system on the 3rd fault in 90 minutes. A lockout will not restart until the operator clears the fault using the keypad. | 210 |
| SYS X YYYYYYYY MOTOR CURRENT OVERLOAD | Software fault; individual system/compressor fault for all systems. Controlled ramped shutdown; locks out on the 1st fault. | Compares the highest of the 3 phases of motor current per compressor to the compressor's 105% FLA ADJUST (overload) potentiometer setting on the VSD Logic Board. If the current exceeds the setting continuously for 20 seconds, the compressor will trip. | Locks out the system on the 1st fault with a controlled ramped shutdown; will not restart until the operator clears the fault using the keypad. | 211 |
| UNIT YYYYYYYY MOTOR CURRENT OVERLOAD | Hardware fault; unit fault that locks out all systems on the first fault. Immediate shutdown. | Compares the highest of the 3 phases of motor current per compressor to the compressor's overload ADJUST potentiometer setting. If the current exceeds the setting continuously for 30 seconds, all compressors will fault and shut down immediately. | Unit fault — locks out all systems on the first fault; will not restart until the operator clears the fault using the keypad. | 211 |
| SYS X YYYYYYYY GATE DRIVER | Hardware fault; system fault for all units. Immediate shutdown. | Each phase bank assembly contains one IGBT gate driver control board per compressor. These boards monitor the saturation voltage drop across each of the six IGBT while gated on. If the IGBT saturation voltage exceeds the prescribed limit, the gate driver determines a short circuit is present, immediately turns off all IGBT in the module and the system shuts down immediately. The same fault is generated if the IGBT Gate Driver board's power supply voltage falls below the permissible limit. | Auto-restart safety: locks out on the 3rd fault in 90 minutes. A lockout will not restart until the operator clears the fault using the keypad. | 211 |
| SYS X YYYYYYYY HIGH VSD BASEPLATE TEMP | Software fault; system fault for all units. Controlled ramped shutdown. | Each compressor's inverter power module contains an internal temperature sensor (5K ohm at 25 Deg. °C) monitoring baseplate temperature. Limit is 218°F on 2-compressor chillers (each system sensor compared individually); 232°F on 3-compressor chillers (compressors 1 and 3 OR'd together, compressor 2 individual); 218°F on 4-compressor chillers (compressors 1/3 OR'd and 2/4 OR'd). If the limit is exceeded, the unit faults and shuts down with a controlled ramped shutdown. | Auto-restart safety: locks out on the 3rd fault in 90 minutes (lockout cleared by the operator via the keypad). After a fault, the fan(s) and water pump remain energized until the inverter power module base plate temperature(s) fall below 165°F; the system is allowed to restart when the base plate temperatures drop below this value. | 212 |
| UNIT YYYYYYYY HIGH VSD INTERNAL AMBIENT TEMP | Software fault; unit fault for all units. Controlled ramped shutdown; does not cause a lockout. | The VSD Logic board contains a temperature sensor which monitors the unit's internal ambient temperature. If the VSD internal ambient temperature rises above the cutout of 158°F, the unit will fault and shut down with a controlled ramped shutdown. | No lockout. The unit will be allowed to restart when the internal ambient temperature drops 10°F below the cutout. | 212 |
| UNIT YYYYYYYY SINGLE PHASE INPUT VOLTAGE 4-compressor units: SYS X YYYYYYYY SINGLE PHASE INPUT VOLTS | Hardware fault. Unit fault on 2- and 3-compressor units; system fault 1/3 or 2/4 on 4-compressor units. No lockout. | The VSD's SCR Trigger Control board contains circuitry that checks the three phase mains for the presence of all three-line voltages. If any of the line voltages are not present, the system will immediately shut down on a fault. | Does not cause a lockout; the system restarts when the single phase condition clears. | 212 |
| UNIT YYYYYYYY VSD LOGIC BOARD POWER SUPPLY | Hardware fault; unit fault for all units. Immediate shutdown. | Various DC power supplies which power the VSD Logic Board are monitored via hardware located on the logic board. If any of these power supplies fall outside their allowable limits, the unit will immediately shut down on a fault. | Auto-restart safety: restarts after the fault clears; locks out on the 3rd fault in 90 minutes. A lockout will not restart until the operator clears the fault using the keypad. | 213 |
| SYS X YYYYYYYY VSD RUN RELAY | Software fault. System fault on 2-compressor units; combined as a 1/3 or 2/4 system fault on 3- and 4-compressor units. Controlled ramped shutdown if running. | Upon receipt of either of the two types of run commands (hardware and software) a 5-second timer commences timing. If the missing run signal is not asserted within the 5-second window, the system will fault. In addition, if either run signal is disabled while the VSD is running, the remaining run signal must be disabled within 5 seconds after the VSD is shut down or the system will fault. | Auto-restart safety: autostarts after the 120-second anti-recycle timer times out; locks out on the 3rd fault in 90 minutes. A lockout will not restart until the operator clears the fault using the keypad. | 213 |
| UNIT YYYYYYYY VSD LOGIC BOARD FAILURE | Software fault; unit fault for all units. All systems shut down immediately if running. | Upon receipt of the voltage and frequency commands, the PWM generator will acknowledge receipt of the command. If the system microprocessor does not receive the handshake within 1.5 seconds of issuing the command, the unit will trip. This safety is only active during precharge and during running of a compressor. | Auto-restart safety: auto restarts after the 120-second anti-recycle timer times out; locks out on the 3rd fault in 90 minutes. | 213 |
| UNIT YYYYYYYY VSD CT PLUG FAULT | Hardware fault; unit fault for all units. Immediate shutdown, or start inhibited if off. | Jumpers are installed in each CT plug on the VSD Logic Board to feed back signals indicating if the plugs are installed or not. If either plug is not installed, a low value is read on the digital input and the unit will immediately shut down on a fault or will not run if off. | Auto-restart safety: restarts after the 120-second anti-recycle timer times out; locks out on the 3rd fault in 90 minutes. A lockout will not restart until the operator clears the fault using the keypad. | 213 |
Unit warnings
| Code / display | Meaning | Cause | Action | Page |
|---|---|---|---|---|
| UNIT WARNING: !! LOW BATTERY !! CHECK SETPOINTS/PROGRAM/OPTIONS/TIME | Displayed indefinitely when the RTC battery voltage is low; can only occur at unit power-up. | On micropanel power-up the RTC battery is checked. If the battery voltage is determined to be low, all programmed setpoints, program values, time, schedule, and history buffers have been lost and are reset to their default values, which may not be the desired operating values. | Replace the battery as soon as possible. The unit is prevented from running until the MANUAL OVERRIDE key is pressed; pressing it sets the anti-recycle timers to the programmed default anti-recycle time to allow the operator sufficient time to check setpoints, program values, etc. Programmed values will be lost and the unit prevented from running on the next power interruption until the battery is replaced. | 215 |
| Flash Card Update Error XXXXX | Error message displayed if an error occurs during a program/database update from the SD flash card; XXXXX is the error code. | Error codes: 0 Okay; 10 Flash card not found; 11 SOFTWARE.BIN file not found; 14 SOFTWARE.BIN file larger than expected; 15 RAM to IPU Flash transfer of DATABASE.BIN failed; 16 RAM to IPU Flash transfer of SOFTWARE.BIN failed; 17 Could not allocate sufficient memory to read or write file; 99 Internal software error. | 217 | |
| UNIT WARNING: INVALID NUMBER OF COMPRESSORS SELECTED | Start-up of the unit is inhibited; warning displayed indefinitely in the Status display. | Occurs after the VSD has been initialized if no "Number of Compressors Select" jumpers are installed or if more than 1 jumper is installed in the J1 plug wiring harness. | To clear this warning, both the control panel and VSD control voltage must be turned off and the jumpers properly installed in the VSD wiring harness. | 218 |
| UNIT WARNING: INVALID SERIAL NUMBER ENTER UNIT SERIAL NUMBER | May mean the chiller has lost important factory programmed information; an Optimized IPLV chiller will only run in Standard IPLV control mode while this warning is present. | Serial number not programmed into the panel (e.g., after changing a Chiller Control Board or EPROM, or if the chiller was not programmed from the factory). | Immediately contact YORK Product Technical Support. Enter the serial number using the Service Key with the factory-provided password. Optimized IPLV cannot be enabled unless the serial number is programmed into the unit. | 218 |
| UNIT WARNING: OPTIMIZED EFFICIENCY DISABLED - CONTACT YORK REPRESENTATIVE | An optimized (High IPLV) chiller is programmed for standard control. | High IPLV mode is not enabled (e.g., after a Chiller Control Board/EPROM change or loss of factory programming). | Immediately contact YORK Product Technical Support or YORK ES Commercial for a password. Once the password is entered and the option is enabled using the Service Key, the message will disappear. | 218 |
Unit safeties
| Code / display | Meaning | Cause | Action | Page |
|---|---|---|---|---|
| UNIT YYYYYYYY LOW AMBIENT TEMP | Unit fault — controlled ramped shutdown; cannot cause a lockout. Occurs only if the Low Ambient Cutout is ENABLED under the OPTIONS key. | The ambient temperature falls below the programmable Low Ambient Temp Cutout. | Restart can occur, if demand allows, when temperature rises 2°F above the cutout. The unit is also inhibited from starting any time the temperature is below the cutout + 2°F. The fault display is present only while the condition exists. | 219 |
| UNIT YYYYYYYY LOW LEAVING CHILLED LIQUID TEMP | Unit fault — controlled ramped shutdown; cannot cause a lockout. Helps protect the chiller from an evaporator freeze-up. | The leaving chilled liquid temperature (water or brine) drops below the programmable cutout point. This situation could occur under low flow conditions or if the micro panel setpoint values are improperly programmed. | Restart can occur, if demand allows, when chilled liquid temperature rises 4°F above the cutout. The unit is inhibited from starting any time the chilled liquid temperature is below the cutout + 4°F. | 220 |
| UNIT YYYYYYYY VSD COMMUNICATIONS FAILURE | Unit fault — controlled ramped shutdown while operating; prevents the unit from trying to run if communications never initialize. | On power-up the Chiller Control Board attempts to initialize communications with the VSD Logic Board (requesting number of compressors and VSD software version); if the connection fails to occur, the chiller is prevented from operating. During normal operation, if the Chiller Control Board receives no valid response to messages for 8 seconds, the unit shuts down all compressors on a Comms fault. | The unit is inhibited from starting until communications is established. The Chiller Control Board continues to send messages to the VSD while faulted. The fault automatically resets when the Chiller Control Board receives a valid response from the VSD for a data request. | 220 |
System safeties: Faults
| Code / display | Meaning | Cause | Action | Page |
|---|---|---|---|---|
| SYS X YYYYYYYY HIGH DISCHARGE PRESSURE | Software fault — controlled ramped shutdown. X indicates the system; YYYYYYYY indicates FAULT (auto-restart) or LOCKOUT. | The discharge pressure rises above 274 psig for 0.5 seconds. | The system is allowed to restart when the discharge pressure falls to 259 psig; it is also inhibited from starting if the pressure is above 259 psig. System faults are auto-reset: the system restarts when the 120-second anti-recycle timer times out. After any 3 faults on the same system within 90 minutes the system locks out on the last fault — a lockout requires a manual reset by cycling the respective system switch OFF and ON. | 221 |
| SYS X YYYYYYYY HPCO FAULT | Mechanical (hardware) high pressure cutout — protects the system from dangerously high discharge pressure. Immediate shutdown; does not wait the typical 3 seconds. Wired in series with the VSD Run Signal; checked only when the system is running. | The mechanical high pressure cutout contacts open. The cutout opens at 297 +/- 8 psig and closes at 230 +/- 10 psig. | The system restarts when the 120-second anti-recycle timer times out; if LOCKOUT is indicated, the system will not restart until the operator clears the fault using the keypad. | 222 |
| SYS X YYYYYYYY LOW SUCTION PRESSURE | Software fault — controlled ramped shutdown. Secondary back-up for the flow switch; protects against operation with low refrigerant charge and helps protect the chiller from evaporator freeze-up. | Suction pressure falls below the programmable cutout (typically 24 psig for chilled water applications). The cutout is ignored for the first 30 seconds of run time; during the next 3 minutes the cutout point is linearly ramped from 10% of the cutout value up to the programmed cutout. After the first 3 minutes 30 seconds of run time, a transient sets a 30-second timer with a linearly ramped cutout starting at 10% of the programmed cutout; if the suction pressure does not stay above the ramped cutout over the 30 seconds, the system faults. | The system restarts when the 120-second anti-recycle timer times out; if LOCKOUT is indicated, the system will not restart until the operator clears the fault using the keypad. | 222 |
| SYS X YYYYYYYY LOW MOTOR CURRENT | Controlled ramped shutdown when the microprocessor detects the absence of motor current, usually indicating that a compressor is not running. | Motor current detected below 10% FLA. This safety is ignored for the first 10 seconds of operation. | The system restarts when the 120-second anti-recycle timer times out; if LOCKOUT is indicated, the system will not restart until the operator clears the fault using the keypad. | 222 |
| SYS X YYYYYYYY HIGH DIFF OIL PRESSURE | Controlled ramped shutdown; protects the compressor from low oil flow and insufficient lubrication, possibly from a dirty oil filter (measures the pressure drop across the oil filter). | Discharge-to-oil differential pressure rises above the cutout of 65 PSID. This safety is ignored for the first 90 seconds of run time. | The system restarts when the 120-second anti-recycle timer times out; if LOCKOUT is indicated, the system will not restart until the operator clears the fault using the keypad. | 223 |
| SYS X YYYYYYYY LOW DIFF OIL PRESSURE | Controlled ramped shutdown; protects the compressor from low oil flow and insufficient lubrication; assures the compressor is pumping sufficiently to push oil through the oil cooling circuit and internal compressor lubrication system. | Differential between oil and suction pressure falls below the cutout. Ignored for the first 60 seconds of run time; thereafter the cutout is linearly ramped from 0 PSID to 30 PSID in 5 to 10 minutes based on ambient temperature (>50°F: 5 min; >45°F: 6 min; >40°F: 7 min; >35°F: 8 min; >30°F: 9 min; ≤30°F: 10 min). A 30-second safety bypass below 50 Hertz applies during rampdown (e.g., when a running compressor is decelerated to 5 Hz to add an additional compressor). | The system restarts when the 120-second anti-recycle timer times out; if LOCKOUT is indicated, the system will not restart until the operator clears the fault using the keypad. | 223 |
| SYS X YYYYYYYY HIGH DSCHARGE TEMP | Controlled ramped shutdown; protects the motor and compressor from overheating. | Discharge temperature rises above 250°F. | The system is also inhibited from starting if the discharge temperature is above 200°F. The system restarts when the 120-second anti-recycle timer times out; if LOCKOUT is indicated, the system will not restart until the operator clears the fault using the keypad. | 223 |
| SYS X YYYYYYYY HIGH OIL TEMP | Controlled ramped shutdown; protects the compressor from insufficient lubrication. | Oil temperature rises above 225°F. | The system is inhibited from starting if the oil temperature is above 175°F. The system restarts when the fault clears (120-second anti-recycle timer); if LOCKOUT is indicated, the system will not restart until the operator clears the fault using the keypad. | 224 |
| SYS X YYYYYYYY LOW SUCTION SUPERHEAT | Controlled ramped shutdown; helps protect the compressor from liquid floodback due to low suction superheat. Ignored for the first 30 seconds of compressor operation. | Faults when any one of the following occur: after the first 30 seconds of run time, suction superheat < 2.0°F, discharge superheat < 15°F and run time < 5 minutes (safety ignored for the next 30 seconds, then the cutout is set to 0°F and linearly ramped up to 2.0°F over 60 seconds — fault if superheat falls below the ramped cutout); suction superheat < 2°F and discharge superheat < 15°F for 10 seconds with run time ≥ 5 minutes; suction superheat < 0.5°F and discharge superheat > 15°F for 60 seconds with run time ≥ 5 minutes; suction superheat < 5°F for 10 minutes. | The system restarts after the 120-second anti-recycle timer times out; if LOCKOUT is indicated, the system will not restart until the operator clears the fault using the keypad. | 224 |
| SYS X YYYYYYYY LOW DISCHARGE SUPERHEAT | Controlled ramped shutdown; helps protect the compressor primarily from liquid floodback through the economizer line due to a high flash tank level, and from liquid floodback through the suction line in conjunction with the low superheat safety. Ignored for the first 5 minutes of compressor operation. | After the first 5 minutes of run time, the discharge superheat falls below 10.0°F for 5 minutes. | The system restarts when the 120-second anti-recycle timer times out; if LOCKOUT is indicated, the system will not restart until the operator clears the fault using the keypad. | 224 |
| SYS X YYYYYYYY SENSOR FAILURE: ZZZZZZZZZZZZ | Prevents the system from running when a critical sensor (transducer, level sensor, or motor winding temp sensor) is not functioning properly and reading out of range. | Checked at start-up and prevents the system from running if one of the sensors has failed; also faults and shuts down a system while in operation if a safety threshold is exceeded or a sensor reads out of range (high or low). ZZZZZZZZZZZZ indicates the failed sensor: SUCT PRESS, OIL PRESS, DSCH PRESS, LEVEL SENSOR, or MOTOR TEMP X. Start-inhibit thresholds: suction/oil/discharge transducers 0.3–4.7 VDC; level sensor 3.0–21.0 mA; motor temp sensor 0–240°F. | YYYYYYYY indicates FAULT (the system restarts when the fault clears) or LOCKOUT after 3 faults — a lockout will not restart until the operator clears the fault using the keypad. The Unit Setup Mode allows a specific motor temperature sensor to be ignored if it fails. | 225 |
| SYS X YYYYYYYY HIGH MOTOR TEMP | Controlled ramped shutdown; prevents a compressor from running when its motor temperature is too high. | Any compressor motor temperature sensor rises above 250°F. | The system is inhibited from starting if its motor temperature sensors indicate temperatures above 240°F. If any single temperature sensor is being ignored under the Unit Set-up Mode, that sensor is not utilized when evaluating motor temperature. The system restarts when the fault clears; if LOCKOUT is indicated, the system will not restart until the operator clears the fault using the keypad. | 225 |
| SYS X YYYYYYYY HIGH FLASH TANK LEVEL | Prevents the system from running when the liquid level in the flash tank is too high. Ignored for the first 15 seconds of system operation. | Tank level greater than 85% for 10 seconds. | The system restarts when the 120-second anti-recycle timer times out; if LOCKOUT is indicated, the system will not restart until the operator clears the fault using the keypad. | 226 |
| SYS X YYYYYYYY CONTROL VOLTAGE | Alerts the operator that the 115V AC control voltage to one of the systems is missing; the affected system faults and shuts down immediately. | Could be due to a system fuse that has been removed or is blown. The safety will not shut down a system if the Unit Switch is OFF (which electrically removes the 115V AC to all systems); it only indicates a situation where a single system is missing the 115V AC. | Does not cause a lockout; the system fault resets when power is returned. | 226 |
Troubleshooting guide
| Code / display | Meaning | Cause | Action | Page |
|---|---|---|---|---|
| Chiller Fault: LOW AMBIENT TEMPERATURE | Ambient temperature is lower than the programmed operating limit. Ambient Sensor is defective. | Check the programmed cutout and determine if it is programmed correctly. Check the panel against the thermometer reading of ambient temperature. | 306 | |
| Chiller Fault: HIGH AMBIENT TEMPERATURE | Ambient Temperature is above the maximum operating limit. Ambient Sensor is defective. | Check outside air temperature. Check the Panel Display against thermometer reading of Ambient Temperature at the sensor. | 306 | |
| Chiller Fault: LOW LEAVING CHILLED LIQUID | Leaving chilled liquid temperature drops faster than the unit can unload (restricted flow; rapid flow changes; water loop too small; flow below minimum for chiller). Chilled Water Sensor is defective. | Check for restricted flow. Check for rapid flow changes. Check Sensor against Temp. Gauge in water line. Check Sensor for intermittent operation. Check Wiring for shorts or opens. | 306 | |
| System Fault: CONTROL VOLTAGE | System Fuse is blown. | Check respective system Fuse 20FU or 21FU. | 306 | |
| System Fault: HIGH OIL TEMPERATURE | Oil Temperature Sensor is defective. Condenser Fans NOT operating or running backwards. Coils dirty. | Check Sensor with infrared to determine if reading is reasonable. Check Fans. Check and clean Coils. | 306 | |
| System Fault: HIGH DISCHARGE PRESSURE | Coils dirty. Coils are damaged. Fans NOT operating. System is overcharged. | Check and clean coils. Comb out fins. Check fan fuses; check fan rotation; check fan motor/blade. Remove charge and check subcooling. | 307 | |
| System Fault: HIGH DISCHARGE TEMPERATURE | Discharge Temperature Sensor is defective. Condenser Fans NOT operating or are running backwards. Coils dirty. High Superheat. | Check Sensor. Check Fans. Check and clean Coils. Measure Superheat with gauges and thermocouple; determine cause. | 307 | |
| System Fault: HIGH MOTOR TEMPERATURE | High Motor temperature input from one of the sensors. Refrigerant charge low. Excess charge in system, high discharge pressure. High Superheat — Drain/Feed Valves NOT controlling. Motor Sensor reading incorrectly. Economizer Solenoid energized at low speeds — valve is leaking through. | Check subcooling. Program panel to ignore a single sensor. Isolate cause of Drain/Feed Valves not controlling. | 307 | |
| System Fault: LOW SUCTION PRESSURE | Low charge. Transducer reads incorrectly. Suction Temp. Sensor reads incorrectly. Low flow. Feed or Drain Valve NOT operating. Feed or Drain Valve defective. | Check subcooling. Check transducer against a gauge. Check sensor against a thermocouple. Check flow. Check Feed and Drain Valve operation; check superheat. | 307 | |
| VSD Fault: High Baseplate Temperature | Coolant level low. Glycol Pump is defective. VSD Board is defective. IBGT Module is defective. | Add coolant. Replace Glycol Pump. Replace VSD Logic Board. Check defective IGBT Module. | 308 | |
| VSD Fault: Low DC Bus Voltage | SCR / Diode Module is defective. SCR Trigger Board is defective. | Check SCR / Diode Module. Check SCR Trigger board. | 308 |
From YCAV0267, YCAV0287, YCAV0307, YCAV0327, YCAV0357, YCAV0397, YCAV0417, YCAV0457, YCAV0477, YCAV0507, YCAV0527 Style A 60 Hz Installation, Operation and Maintenance 201.21-NM3
Original: docs.johnsoncontrols.com
VSD safeties (faults)
| Code / display | Meaning | Cause | Action | Page |
|---|---|---|---|---|
| UNIT YYYYYYYY PRECHARGE - LOW DC BUS VOLTAGE SYS X YYYYYYYY PRECHARGE - LOW DC BUS VOLT | Pre-charge Low DC Bus Voltage (Software) Fault. DC bus voltage did not reach at least 50 VDC within 4 seconds and 500 VDC within 19 seconds after the pre-charge signal was asserted. | Auto-restart safety; unit/system shuts down and restarts when the fault clears. Locks out on the 3rd fault in 90 minutes. Unit fault on 2- and 3-compressor chillers; System 1/3 or 2/4 fault on 4-compressor chillers. A LOCKOUT will not restart until the operator clears the fault using the keypad. | 246 | |
| UNIT YYYYYYYY PRECHARGE - DC BUS VOLTAGE IMBALANCE SYS X YYYYYYYY PRECHARGE-BUS VOLT IMBAL | Pre-charge DC Bus Voltage Imbalance (Software) Fault. During the pre-charge interval the 1/2 DC bus voltage magnitude must remain within +/-100 VDC of the total DC bus voltage divided by two; unit/system shuts down if it does not. | Locks out on the 1st fault. Unit fault on 2- and 3-compressor chillers; System 1/3 or 2/4 fault on 4-compressor chillers (two presses of the STATUS key required to show the fault on both systems). Operator must clear the lockout using the keypad. | 246 | |
| UNIT YYYYYYYY HIGH DC BUS VOLTAGE SYS X YYYYYYYY HIGH DC BUS VOLTAGE | High DC Bus Voltage (Hardware) Fault. Trip level determined by hardware on the VSD Logic Board at 766 +/- 30 VDC; unit/system faults and shuts down immediately if the DC bus exceeds this level. | Auto-restart safety; locks out on the 3rd fault in 90 minutes. Unit fault on 2- and 3-compressor chillers; System 1/3 or 2/4 fault on 4-compressor chillers. | 246 | |
| UNIT YYYYYYYY LOW DC BUS VOLTAGE SYS X YYYYYYYY LOW DC BUS VOLTAGE | Low DC Bus Voltage (Software) Fault. Trip level set at 500 VDC; unit/system faults and shuts down immediately if the DC bus drops below this level. | Auto-restart safety; locks out on the 3rd fault in 90 minutes. Unit fault on 2- and 3-compressor chillers; System 1/3 or 2/4 fault on 4-compressor chillers. | 247 | |
| UNIT YYYYYYYY DC BUS VOLTAGE IMBALANCE SYS X YYYYYYYY DC BUS VOLTAGE IMBALANCE | DC Bus Voltage Imbalance (Software) Fault. The 1/2 DC bus voltage magnitude must remain within +/-100 VDC of the total DC bus voltage divided by two; unit/system faults and shuts down immediately if exceeded. | Locks out on the 1st fault. Unit fault on 2- and 3-compressor chillers; System 1/3 or 2/4 fault on 4-compressor chillers. | 247 | |
| SYS X YYYYYYYY HIGH MOTOR CURRENT | High Motor Current (Hardware) Fault. Three phases of instantaneous output current per compressor compared to a predetermined hardware limit. Nominal peak current trip level 575.5 Amps (554 A min., 597 A max.); 380V AC 60 Hz and 400V AC 50 Hz nominal peak trip level 649.5 Amps (626 A min., 674 A max.). Immediate shutdown if the peak current limit is exceeded. | Auto-restart safety; locks out the system on the 3rd fault in 90 minutes. Individual system/compressor fault for all units. | 247 | |
| SYS X YYYYYYYY MOTOR CURRENT OVERLOAD | Motor Current Overload (Software) Fault. Highest of the 3 phases of motor current per compressor compared to the compressor's 105% FLA ADJUST (overload) potentiometer setting on the VSD Logic Board; compressor trips if the setting is exceeded continuously for 20 seconds. Controlled ramped shutdown. | Locks out the system on the 1st fault. Individual system/compressor fault for all systems. | 248 | |
| UNIT YYYYYYYY MOTOR CURRENT OVERLOAD | Motor Current Overload (Hardware) Fault. Highest of the 3 phases of motor current per compressor compared to the compressor's overload ADJUST potentiometer setting; if exceeded continuously for 30 seconds, all compressors fault and shut down immediately. | Unit fault; locks out all systems on the first fault. Will not restart until the operator clears the fault using the keypad. | 248 | |
| SYS X YYYYYYYY GATE DRIVER | IGBT Gate Driver (Hardware) Fault. Gate driver board monitors the saturation voltage drop across each of the six IGBTs while gated on; if the saturation voltage exceeds the prescribed limit a short circuit is determined and all IGBTs in the module are turned off immediately. The same fault is generated if the gate driver board power supply voltage falls below the permissible limit. | Auto-restart safety; locks out on the 3rd fault in 90 minutes. System fault for all units. | 248 | |
| SYS X YYYYYYYY HIGH VSD BASEPLATE TEMP | High Baseplate Temperature (Software) Fault. Limits: 2-compressor chillers — System 1 and System 2 sensors each compared to 218°F; 3-compressor chillers — compressors 1 and 3 OR'd, highest compared to 232°F, compressor #2 individually to 232°F; 4-compressor chillers — compressors 1/3 OR'd and 2/4 OR'd, each compared to 218°F. Controlled ramped shutdown when the limit is exceeded. | Auto-restart safety; locks out on the 3rd fault in 90 minutes. System fault for all units. After a fault the fan(s) and water pump remain energized until the inverter power module base plate temperature(s) fall below 165°F; the system is allowed to restart when the base plate temperatures drop below this value. | 249 | |
| UNIT YYYYYYYY HIGH VSD INTERNAL AMBIENT TEMP | High VSD Internal Ambient Temperature (Software) Fault. VSD internal ambient temperature rises above the cutout of 158°F; controlled ramped shutdown. | This safety will not cause a lockout. Unit fault for all units. Unit allowed to restart when the internal ambient temperature drops 10°F below the cutout. | 249 | |
| UNIT YYYYYYYY SINGLE PHASE INPUT VOLTAGE SYS X YYYYYYYY SINGLE PHASE INPUT VOLTS | Single Phase Input (Hardware) Fault. The VSD's SCR Trigger Control board checks the three-phase mains for the presence of all three line voltages; immediate shutdown if any line voltage is not present. | Does not cause a lockout. Unit fault on 2- and 3-compressor chillers; System 1/3 or 2/4 fault on 4-compressor chillers. Restarts when the single phase condition clears. | 249 | |
| UNIT YYYYYYYY VSD LOGIC BOARD POWER SUPPLY | Power Supply (Hardware) Fault. Various DC power supplies which power the VSD Logic Board are monitored via hardware; immediate shutdown if any supply falls outside its allowable limits. | Auto-restart safety; restarts after the fault clears and locks out on the 3rd fault in 90 minutes. Unit fault for all units. | 250 | |
| SYS X YYYYYYYY VSD RUN RELAY | Run Relay (Software) Fault. Upon receipt of a run command (hardware and software) a 5-second timer commences; the system faults if the missing run signal is not asserted within the 5-second window. If either run signal is disabled while the VSD is running, the remaining run signal must be disabled within 5 seconds after the VSD is shut down or the system faults. Controlled ramped shutdown if running. | Auto-restart safety; autostarts after the 120-second anti-recycle timer times out and locks out on the 3rd fault in 90 minutes. System fault on 2-compressor units; combined 1/3 or 2/4 system fault on 3- and 4-compressor units. | 250 | |
| UNIT YYYYYYYY VSD LOGIC BOARD FAILURE | VSD Logic Board Failure (Software) Fault. The PWM generator does not acknowledge the voltage and frequency commands within 1.5 seconds of issue. Active only during precharge and while a compressor is running; if it occurs while the chiller is running, all systems immediately shut down. | Auto-restart safety; auto restarts after the 120-second anti-recycle timer times out and locks out on the 3rd fault in 90 minutes. Unit fault for all units. | 250 | |
| UNIT YYYYYYYY VSD CT PLUG FAULT | VSD CT Plug (Hardware) Fault. Jumpers installed in each CT plug on the VSD Logic Board feed back signals indicating the plugs are installed; if either plug is not installed a low value is read on the digital input and the unit shuts down immediately or will not run if off. | Auto-restart safety; restarts after the 120-second anti-recycle timer times out and locks out on the 3rd fault in 90 minutes. Unit fault for all units. | 250 |
Unit warnings
| Code / display | Meaning | Cause | Action | Page |
|---|---|---|---|---|
| UNIT WARNING: !! LOW BATTERY !! CHECK SETPOINTS/PROGRAM/OPTIONS/TIME | Low Battery Warning. Occurs only at unit power-up; the RTC battery voltage is determined to be low. All programmed setpoints, program values, time, schedule, and history buffers have been lost and reset to default values, which may not be the desired operating values. | Low RTC battery (located on the Chiller Logic Board). | Unit is prevented from running until the MANUAL OVERRIDE key is pressed; anti-recycle timers are then set to the programmed default to allow the operator time to check setpoints, program values, etc. Replace the battery as soon as possible. | 252 |
| UNIT WARNING: INVALID NUMBER OF COMPRESSORS SELECTED | Invalid Number of Compressors Warning. Occurs after the VSD has been initialized. | No "Number of Compressors Select" jumpers installed, or more than 1 jumper installed in the VSD wiring harness (J1 plug). | To clear the warning, both the control panel and VSD control voltage must be turned off and the jumpers properly installed in the VSD wiring harness. Start-up of the unit is inhibited while the warning is present. | 255 |
| UNIT WARNING: INVALID SERIAL NUMBER ENTER UNIT SERIAL NUMBER | Invalid Serial Number Warning. May mean the chiller has lost important factory programmed information. An Optimized IPLV chiller will only run in Standard IPLV control mode while this warning is present. | Serial number not programmed into the panel / factory programmed information lost. | Immediately contact YORK Product Technical Support. Enter the serial number using the Service Key with the factory-provided password (date/time must be set first; password is time sensitive). Message can be bypassed to view additional STATUS messages by pressing the STATUS key repeatedly. | 255 |
| UNIT WARNING: OPTIMIZED EFFICIENCY DISABLED - CONTACT YORK REPRESENTATIVE | Optimized Efficiency Disabled warning. Means an optimized (High IPLV) chiller is programmed for standard control. | High IPLV (Optimized) mode not enabled. | Immediately contact YORK Product Technical Support or YORK ES Commercial for a password. Enable Optimized IPLV via the Service Key; the message disappears once enabled. Message can be bypassed to view additional STATUS messages by pressing the STATUS key repeatedly. | 255 |
Flash card update error XXXXX
| Code / display | Meaning | Cause | Action | Page |
|---|---|---|---|---|
| Error code 10 | Flash card not found. | 254 | ||
| Error code 11 | SOFTWARE.BIN file not found | 254 | ||
| Error code 14 | SOFTWARE.BIN file larger than expected. | 254 | ||
| Error code 15 | RAM to IPU Flash transfer of DATABASE.BIN failed. | 254 | ||
| Error code 16 | RAM to IPU Flash transfer of SOFTWARE.BIN failed. | 254 | ||
| Error code 17 | Could not allocate sufficient memory to read or write file. | 254 | ||
| Error code 99 | Internal software error. | 254 |
Unit safeties
| Code / display | Meaning | Cause | Action | Page |
|---|---|---|---|---|
| UNIT YYYYYYYY LOW AMBIENT TEMP | Low Ambient Temp Fault. Ambient temperature falls below the programmable Low Ambient Temp Cutout; controlled ramped shutdown. Only occurs if the Low Ambient Cutout is "ENABLED" under the OPTIONS key. | Cannot cause a lockout. Restart, if demand allows, when temperature rises 2°F above the cutout. Unit is also inhibited from starting any time the temperature is below the cutout + 2°F. | 256 | |
| UNIT YYYYYYYY LOW LEAVING CHILLED LIQUID TEMP | Low Leaving Chilled Liquid Temp Fault. Leaving chilled liquid temperature drops below the programmable cutout point; helps protect the chiller from evaporator freeze-up. Controlled ramped shutdown. | Low flow conditions or improperly programmed micro panel setpoint values. | Cannot cause a lockout. Restart, if demand allows, when chilled liquid temperature rises 4°F above the cutout. Unit is inhibited from starting any time the chilled liquid temperature is below the cutout + 4°F. | 257 |
| UNIT YYYYYYYY VSD COMMUNICATIONS FAILURE | VSD Communications Failure Fault. Chiller Control Board never initializes communications with the VSD Logic Board, or receives no valid response to messages for 8 seconds during operation; all compressors shut down with a controlled ramped shutdown. | Unit is inhibited from starting until communications is established. The Chiller Control Board continues sending messages to the VSD while faulted. Fault automatically resets when the Chiller Control Board receives a valid response from the VSD. | 257 |
System safeties (faults)
| Code / display | Meaning | Cause | Action | Page |
|---|---|---|---|---|
| SYS X YYYYYYYY HIGH DISCHARGE PRESSURE | High Discharge Pressure Cutout (Software) Fault. Discharge pressure rises above 274 PSIG for 0.5 seconds; controlled ramped shutdown. | System allowed to restart when discharge pressure falls to 259 PSIG; inhibited from starting if the pressure is above 259 PSIG. Auto-restarts after the 120-second anti-recycle timer; locks out after 3 faults on the same system within 90 minutes (lockout cleared by cycling the system switch OFF and ON). | 258 | |
| SYS X YYYYYYYY HPCO FAULT | High Discharge Pressure Cutout (HPCO) (Hardware) Fault. Mechanical high pressure cutout contacts open; immediate fault and shutdown (does not wait 3 seconds). Wired in series with the VSD Run Signal and checked only when the system is running. Cutout opens at 297 +/-8 PSIG and closes at 230 +/-10 PSIG. | Restarts when the 120-second anti-recycle timer times out; locks out after 3 faults on the same system within 90 minutes (lockout cleared by cycling the system switch OFF and ON). | 259 | |
| SYS X YYYYYYYY LOW SUCTION PRESSURE | Low Suction Pressure Cutout (Software) Fault. Programmable secondary back-up for the flow switch; protects against operation with low refrigerant charge and evaporator freeze-up. Ignored for the first 30 seconds of run time; over the next 3 minutes the cutout ramps linearly from 10% of the programmed cutout up to the programmed point. After 3 minutes 30 seconds, a transient override sets a 30-second linearly ramped cutout starting at 10% of the programmed cutout. Typically set at 24 PSIG for chilled water applications. Controlled ramped shutdown. | Auto-restarts after the 120-second anti-recycle timer; locks out after 3 faults on the same system within 90 minutes (lockout cleared by cycling the system switch OFF and ON). | 259 | |
| SYS X YYYYYYYY LOW MOTOR CURRENT | Low Motor Current Cutout Fault. Absence of motor current (<10%FLA) detected, usually indicating that a compressor is not running; controlled ramped shutdown. Ignored for the first 10 seconds of operation. | Auto-restarts after the 120-second anti-recycle timer; locks out after 3 faults on the same system within 90 minutes (lockout cleared by cycling the system switch OFF and ON). | 259 | |
| SYS X YYYYYYYY HIGH DIFF OIL PRESSURE | High Differential Oil Pressure Cutout Fault. Discharge-to-oil differential pressure (the pressure drop across the oil filter) rises above the cutout of 65 PSID; protects the compressor from low oil flow and insufficient lubrication. Ignored for the first 90 seconds of run time. Controlled ramped shutdown. | Possibly a dirty oil filter. | Auto-restarts after the 120-second anti-recycle timer; locks out after 3 faults on the same system within 90 minutes (lockout cleared by cycling the system switch OFF and ON). | 260 |
| SYS X YYYYYYYY LOW DIFF OIL PRESSURE | Low Differential Oil Pressure Cutout Fault. Differential between oil and suction pressure falls below the cutout; assures the compressor is pumping sufficiently to push oil through the oil cooling circuit and internal lubrication system. Ignored for the first 60 seconds of run time; cutout then ramps linearly from 0 PSID to 30 PSID over 5–10 minutes based on ambient temperature (>50°F: 5 min; >45°F: 6 min; >40°F: 7 min; >35°F: 8 min; >30°F: 9 min; ≤30°F: 10 min). A 30-second safety bypass below 50 Hertz applies during rampdown. Controlled ramped shutdown. | Auto-restarts after the 120-second anti-recycle timer; locks out after 3 faults on the same system within 90 minutes (lockout cleared by cycling the system switch OFF and ON). | 260 | |
| SYS X YYYYYYYY HIGH DSCHARGE TEMP | High Discharge Temperature Cutout Fault. Discharge temperature rises above 250°F; protects the motor and compressor from overheating. Controlled ramped shutdown. | System inhibited from starting if discharge temperature is above 200°F. Auto-restarts after the 120-second anti-recycle timer; locks out after 3 faults on the same system within 90 minutes (lockout cleared by cycling the system switch OFF and ON). | 260 | |
| SYS X YYYYYYYY HIGH OIL TEMP | High Oil Temperature Cutout Fault. Oil temperature rises above 225°F; protects the compressor from insufficient lubrication. Controlled ramped shutdown. | System inhibited from starting if oil temperature is above 175°F. Auto-restarts after the 120-second anti-recycle timer; locks out after 3 faults on the same system within 90 minutes (lockout cleared by cycling the system switch OFF and ON). | 261 | |
| SYS X YYYYYYYY LOW SUCTION SUPERHEAT | Low Suction Superheat Cutout Fault. Helps protect the compressor from liquid floodback due to low suction superheat. Ignored for the first 30 seconds of compressor operation. Faults when any of the following occur: after the first 30 seconds, suction superheat <2.0°F with discharge superheat <15°F and run time <5 minutes (cutout set to 0°F and linearly ramped to 2.0°F over the next 60 seconds); suction superheat <2°F and discharge superheat <15°F for 10 seconds with run time ≥5 minutes; suction superheat <0.5°F with discharge superheat >15°F for 60 seconds and run time ≥5 minutes; suction superheat <5°F for 10 minutes. Controlled ramped shutdown. | Auto-restarts after the 120-second anti-recycle timer; locks out after 3 faults on the same system within 90 minutes (lockout cleared by cycling the system switch OFF and ON). | 261 | |
| SYS X YYYYYYYY LOW DISCHARGE SUPERHEAT | Low Discharge Superheat Cutout Fault. Helps protect the compressor primarily from liquid floodback through the economizer line due to a high flash tank level; also provides suction-line floodback protection in conjunction with the low superheat safety. Ignored for the first 5 minutes of compressor operation. After the first 5 minutes of run time, faults if discharge superheat falls below 10.0°F for 5 minutes. Controlled ramped shutdown. | Auto-restarts after the 120-second anti-recycle timer; locks out after 3 faults on the same system within 90 minutes (lockout cleared by cycling the system switch OFF and ON). | 261 | |
| SYS X YYYYYYYY SENSOR FAILURE: ZZZZZZZZZZZZ | Sensor Failure Cutout Fault. Critical sensor (transducer, level sensor, or motor winding temp sensor) not functioning properly and reading out of range. Checked at start-up and prevents the system from running; also faults and shuts down a running system. ZZZZZZZZZZZZ indicates the failed sensor: SUCT PRESS, OIL PRESS, DSCH PRESS, LEVEL SENSOR, or MOTOR TEMP X. Start inhibit thresholds: suction/oil/discharge transducers 0.3–4.7 VDC; level sensor 3.0–21.0 mA; motor temp sensor 0–240°F. | Critical sensor failed or reading out of range. | Restarts when the fault clears; locks out after 3 faults (operator clears via the keypad). The Unit Setup Mode allows a specific motor temperature sensor to be ignored if it fails. | 262 |
| SYS X YYYYYYYY HIGH MOTOR TEMP | High Motor Temperature Cutout Fault. Any compressor motor temperature sensor rises above 250°F; prevents a compressor from running when its motor temperature is too high. | System inhibited from starting if its motor temperature sensors indicate temperatures above 240°F. A sensor being ignored under the Unit Set-up Mode is not utilized when evaluating motor temperature. Auto-restarts when the fault clears; locks out after 3 faults on the same system within 90 minutes (lockout cleared by cycling the system switch OFF and ON). | 262 | |
| SYS X YYYYYYYY HIGH FLASH TANK LEVEL | High Flash Tank Level Cutout Fault. Liquid level in the flash tank is too high. Ignored for the first 15 seconds of system operation; fault occurs if the tank level is greater than 85% for 10 seconds. | Auto-restarts after the 120-second anti-recycle timer; locks out after 3 faults on the same system within 90 minutes (lockout cleared by cycling the system switch OFF and ON). | 263 | |
| SYS X YYYYYYYY CONTROL VOLTAGE | System Control Voltage Cutout Fault. Alerts the operator that the 115V AC control voltage to one of the systems is missing; the affected system faults and shuts down immediately when the 115V AC supply is lost. Does not shut down a system if the Unit Switch is OFF (which removes 115V AC to all systems). | A system fuse has been removed or is blown. | Will not cause a lockout; the system fault resets when power is returned. | 263 |
ISN fault and inhibit codes
| Code / display | Meaning | Cause | Action | Page |
|---|---|---|---|---|
| 1 | Low Ambient Temp. (Unit / Panel) | 329 | ||
| 2 | High Ambient Temp. (Unit / Panel) | 329 | ||
| 3 | Low Chilled Liquid Temp. (Unit / Panel) | 329 | ||
| 5 | Low RTC Battery Voltage (Unit / Panel) | 329 | ||
| 6 | Invalid Number of Compressors Selected (Unit / Panel) | 329 | ||
| 7 | VSD Communications Failure (Unit / Panel) | 329 | ||
| 8 | Pre-charge Low DC Bus Voltage (Unit / VSD) | 329 | ||
| 9 | Pre-charge DC Bus Voltage Imbalance (Unit / VSD) | 329 | ||
| 10 | High DC Bus Voltage (Unit / VSD) | 329 | ||
| 11 | Low DC Bus Voltage (Unit / VSD) | 329 | ||
| 12 | DC Bus Voltage Imbalance (Unit / VSD) | 329 | ||
| 13 | High VSD Ambient Temp. (Unit / VSD) | 329 | ||
| 14 | Single Phase Input (Unit / VSD) | 329 | ||
| 15 | VSD Power Supply Fault (Unit / VSD) | 329 | ||
| 16 | VSD Logic Board Fault (Unit / VSD) | 329 | ||
| 17 | Motor Current Overload (Hardware) (Unit / VSD) | 329 | ||
| 18 | CT Plug Fault (Unit / VSD) | 329 | ||
| 27 | High Discharge Pressure (Software) (System / Panel) | 329 | ||
| 28 | High Differential Oil Pressure (System / Panel) | 329 | ||
| 29 | Low Differential Oil Pressure (System / Panel) | 329 | ||
| 30 | Low Suction Pressure (System / Panel) | 329 | ||
| 31 | High Discharge Temp. (System / Panel) | 329 | ||
| 32 | High Oil Temp. (System / Panel) | 329 | ||
| 33 | Low Suction Superheat (System / Panel) | 329 | ||
| 34 | Sensor Failure (System / Panel) | 329 | ||
| 35 | Low Motor Current (System / Panel) | 329 | ||
| 36 | High Motor Temperature (System / Panel) | 329 | ||
| 37 | Pre-charge Low DC Bus Voltage (System / VSD) | 330 | ||
| 38 | Pre-charge DC Bus Voltage Imbalance (System / VSD) | 330 | ||
| 39 | High Dc Bus Voltage (System / VSD) | 330 | ||
| 40 | Low DC Bus Voltage (System / VSD) | 330 | ||
| 41 | DC Bus Voltage Imbalance (System / VSD) | 330 | ||
| 42 | High Motor Current (System / VSD) | 330 | ||
| 43 | Motor Current Overload (Software) (System / VSD) | 330 | ||
| 44 | IGBT Gate Driver Fault (System / VSD) | 330 | ||
| 45 | High Baseplate Temp. (System / VSD) | 330 | ||
| 46 | Single Phase Input (System / VSD) | 330 | ||
| 47 | VSD Run Signal Fault (System / VSD) | 330 | ||
| 48 | High Discharge Press (Hardware-HPCO) (System / Panel) | 330 | ||
| 49 | High Flash Tank Level (System / Panel) | 330 | ||
| 50 | Control Voltage Fault (System / Panel) | 330 | ||
| 51 | Low Discharge Superheat (System / Panel) | 330 |
Troubleshooting guide
| Code / display | Meaning | Cause | Action | Page |
|---|---|---|---|---|
| No Display on Control Panel. Unit will NOT Run. | Supply to the Panel is missing. High Voltage to the Chiller is missing. Line Fuse is blown. Chiller Control board is defective. Display Board defective. | Check 1FU, 2FU, 4FU, 5FU 17FU, or 19FU. Check 2T or 10T Transformer. Check Fuses. Replace Chiller Control board Replace Display Board | 337 | |
| Line Fuse Blows. | SCR Diode Module is defective. IGBT Module is defective. VSD Logic Board is defective. SCR Trigger Board is defective | Check SCR/Diode Module. Check IGBT Module. Replace VSD Logic Board. Replace SCR Trigger Board. | 337 | |
| Chiller Fault: LOW AMBIENT TEMPERATURE | Ambient temperature is lower than the programmed operating limit. Ambient Sensor is defective. | Check the programmed cutout and determine if it is programmed correctly Check the panel against the thermometer reading of ambient temperature | 337 | |
| Chiller Fault: HIGH AMBIENT TEMPERATURE | Ambient Temperature is above the maximum operating limit. Ambient Sensor is defective. | Check outside air temperature. Check the Panel Display against Thermometer reading of Ambient Temperature at the sensor. | 337 | |
| Chiller Fault: LOW LEAVING CHILLED LIQUID | Leaving chilled liquid temperature drops faster than the unit can unload. Water loop is too small. Flow is below minimum for chiller. Chilled Water Sensor is defective. | Check for restricted flow. Check for rapid flow changes. Check Sensor against Temp. Gauge in water line. Check Sensor for intermittent operation. Check Wiring for shorts or opens. | 337 | |
| System Fault: CONTROL VOLTAGE | System Fuse is blown. | Check respective system Fuse 20FU or 21FU. | 337 | |
| System Fault: HIGH OIL TEMPERATURE | Oil Temperature Sensor is defective. Condensor Fans NOT operating or running backwards. Coils dirty. | Check Sensor with infrared to determine if reading is reasonable. Check Fans. Check and clean Coils. | 337 | |
| System Fault: HIGH DISCHARGE PRESSURE | Coils dirty. Coils are damaged. Fans NOT operating. System is overcharged. | Check and clean coils. Comb out fins. Check fan fuses. Check fan rotation. Check fan motor/blade. Remove charge and check subcooling. | 338 | |
| System Fault: HIGH DISCHARGE TEMPERATURE | Discharge Temperature Sensor is defective. Condensor Fans NOT operating or are running backwards. Coils dirty. High Superheat. | Check Sensor. Check Fans. Check and clean Coils. Measure Superheat with gauges and thermocouple. Determine cause. | 338 | |
| System Fault: HIGH MOTOR TEMPERATURE | High Motor temperature input from one of the sensors Refrigerant charge low. Excess charge in system, High discharge pressure. High Superheat. Motor Sensor reading incorrectly. Economizer Solenoid energized at low speeds. Valve is leaking through. | Check subcooling. Check subcooling. Drain/Feed Valves NOT controlling. Isolate cause. Program panel to ignore a single sensor. | 338 | |
| System Fault: LOW SUCTION PRESSURE | Low charge. Transducer reads incorrectly. Suction Temp. Sensor reads incorrectly. Low flow. Feed or Drain Valve NOT operating Feed or Drain Valve defective. | Check subcooling. Check transducer against a gauge. Check sensor against a thermocouple. Check flow. Check Feed and Drain Valve operation. Check superheat. Check Feed and Drain Valve operation. Check superheat. | 338 | |
| System Fault: DISCHARGE PRESSURE LIMITING | Discharge Transducer is defective. Ambient Temp. very high. Fans NOT operating. Remote or local discharge pressure load limiting is programmed. | Check transducer against a gauge. Normal operation. Check fan operation. Normal operation. | 338 | |
| System Fault: MOTOR CURRENT LIMITING | High motor current has activated current limiting Ambient temperature is high, Remote or panel limiting is in effect, Excess charge in system, Condensor coils dirty, Fans NOT operating, | normal response from controller Normal response. adjust charge. Clean condensor. Check fans. | 339 | |
| VSD Fault: High Baseplate Temperature | Coolant level low. Glycol Pump is defective. VSD Board is defective IGBT Module is defective. | Add coolant. Replace Glycol Pump. Replace VSD Logic Board. Check defective IGBT Module. | 339 | |
| VSD Fault: Low DC Bus Voltage | SCR / Diode Module is defective. SCR Trigger Board is defective. | Check SCR / Diode Module. Check SCR Trigger board. | 339 |
From YCAV0569, YCAV0639, YCAV0679, YCAV0719, YCAV0739, YCAV0819, YCAV0889, YCAV0969 Style A 50 Hz Installation, Operation and Maintenance 201.21-NM2
Original: docs.johnsoncontrols.com
VSD SAFETIES (FAULTS)
| Code / display | Meaning | Cause | Action | Page |
|---|---|---|---|---|
| UNIT YYYYYYYY PRECHARGE - LOW DC BUS VOLTAGE SYS X YYYYYYYY PRECHARGE - LOW DC BUS VOLT | DC bus voltage failed to reach minimum levels during pre-charge interval | DC bus voltage did not reach at least 50 VDC within four seconds and 500 VDC within 19 seconds after the pre-charge signal was asserted | Auto-restart safety. Locks out on 3rd fault in 90 minutes. Lockout requires manual reset using keypad. | 173 |
| UNIT YYYYYYYY PRECHARGE - DC BUS VOLTAGE IMBALANCE SYS X YYYYYYYY PRECHARGE-BUS VOLT IMBAL | Half-bus voltage deviated beyond tolerance during pre-charge interval | The 1/2 DC bus voltage magnitude exceeded +/- 100 VDC of the total DC bus voltage divided by two during the pre-charge interval | Locks out on 1st fault. Will not restart until operator clears the fault using the keypad. | 173 |
| UNIT YYYYYYYY HIGH DC BUS VOLTAGE SYS X YYYYYYYY HIGH DC BUS VOLTAGE | DC bus voltage exceeded hardware trip level | DC bus exceeded 766 +/- 30 VDC hardware trip level on the VSD Logic Board | Immediate shutdown. Auto-restart safety. Locks out on 3rd fault in 90 minutes. | 173 |
| UNIT YYYYYYYY LOW DC BUS VOLTAGE SYS X YYYYYYYY LOW DC BUS VOLTAGE | DC bus voltage dropped below software trip level | DC bus dropped below 500 VDC | Immediate shutdown. Auto-restart safety. Locks out on 3rd fault in 90 minutes. | 174 |
| UNIT YYYYYYYY DC BUS VOLTAGE IMBALANCE SYS X YYYYYYYY DC BUS VOLTAGE IMBALANCE | Half-bus voltage deviated beyond tolerance during operation | The 1/2 DC bus magnitude exceeded the +/- 100 VDC tolerances of the total DC bus voltage divided by two | Immediate shutdown. Locks out on 1st fault. Will not restart until operator clears the fault using the keypad. | 174 |
| SYS X YYYYYYYY HIGH MOTOR CURRENT | Instantaneous peak motor current exceeded hardware limit | Nominal peak current trip level is 575.5 Amps (554A min., 597A max.). 380V AC, 60Hz and 400V AC, 50Hz nominal peak current trip level is 649.5 Amps (626 Amps min., 674 Amps max.) | Immediate shutdown. Auto-restart safety. Locks out system on 3rd fault in 90 minutes. | 174 |
| SYS X YYYYYYYY MOTOR CURRENT OVERLOAD | Highest phase motor current exceeded overload setting continuously for 20 seconds | Highest of the 3 phases of motor current per compressor exceeded the compressor's 105% FLA ADJUST potentiometer setting on the VSD Logic Board continuously for 20 seconds | Controlled ramped shutdown. Locks out system on 1st fault. Will not restart until operator clears the fault using the keypad. | 175 |
| UNIT YYYYYYYY MOTOR CURRENT OVERLOAD | Highest phase motor current exceeded overload setting continuously for 30 seconds across all compressors | Highest of the 3 phases of motor current per compressor exceeded the compressor's overload ADJUST potentiometer setting continuously for 30 seconds | Immediate shutdown. Locks out all systems on 1st fault. Will not restart until operator clears the fault using the keypad. | 175 |
| SYS X YYYYYYYY GATE DRIVER | IGBT short circuit detected or gate driver power supply low | IGBT saturation voltage (VCE SAT) exceeded prescribed limit due to short circuit condition, or IGBT Gate Driver board power supply voltage fell below permissible limit | Immediate shutdown. Auto-restart safety. Locks out on 3rd fault in 90 minutes. | 175 |
| SYS X YYYYYYYY HIGH VSD BASEPLATE TEMP | IGBT baseplate temperature exceeded software trip point | Baseplate temperature exceeded limit — 218°F for 2 and 4 compressor chillers, 232°F for 3 compressor chillers | Controlled ramped shutdown. Auto-restart safety. Locks out on 3rd fault in 90 minutes. Fans and water pump remain energized until baseplate temperature falls below 165°F; restart allowed when temperature drops below this value. | 176 |
| UNIT YYYYYYYY HIGH VSD INTERNAL AMBIENT TEMP | VSD internal cabinet ambient temperature rose above cutout | VSD internal ambient temperature rose above the cutout of 158°F | Controlled ramped shutdown. Does not cause lockout. Restarts when internal ambient temperature drops 10°F below the cutout (148°F). | 176 |
| UNIT YYYYYYYY SINGLE PHASE INPUT VOLTAGE SYS X YYYYYYYY SINGLE PHASE INPUT VOLTS | One of three input line voltages missing | SCR Trigger Control board circuitry detected absence of any of the three-phase line voltages | Immediate shutdown. Does not cause lockout. Restarts when the single phase condition clears. | 176 |
| UNIT YYYYYYYY VSD LOGIC BOARD POWER SUPPLY | One or more DC power supplies to VSD Logic Board outside allowable limits | Monitored DC power supplies on the VSD Logic Board fell outside their allowable limits | Immediate shutdown. Auto-restart safety. Restarts after fault clears. Locks out on 3rd fault in 90 minutes. | 177 |
| SYS X YYYYYYYY VSD RUN RELAY | Hardware and software run signals did not match within 5-second window | Missing run signal not asserted within the 5-second window, or remaining run signal not disabled within 5 seconds after the VSD was shut down | Controlled ramped shutdown if running. Auto-restart safety. Autostarts after 120 second anti-recycle timer times out. Locks out on 3rd fault in 90 minutes. | 177 |
| UNIT YYYYYYYY VSD LOGIC BOARD FAILURE | PWM generator did not acknowledge voltage and frequency commands | System microprocessor did not receive handshake from PWM generator within 1.5 seconds of issuing the command | All systems immediately shut down. Auto-restart safety. Auto restarts after 120 second anti-recycle timer. Locks out on 3rd fault in 90 minutes. | 177 |
| UNIT YYYYYYYY VSD CT PLUG FAULT | CT plug not installed on VSD Logic Board | Jumper in CT plug not installed, causing a low value read on the digital input | Immediate shutdown or prevented from running. Auto-restart safety. Restarts after 120 second anti-recycle timer. Locks out on 3rd fault in 90 minutes. | 177 |
UNIT WARNINGS
| Code / display | Meaning | Cause | Action | Page |
|---|---|---|---|---|
| UNIT WARNING: !! LOW BATTERY !! CHECK SETPOINTS/PROGRAM/OPTIONS/TIME | RTC battery voltage low at power-up | RTC battery determined to be low at micropanel power-up | All programmed setpoints, program values, time, schedule, and history buffers lost and reset to defaults. Unit prevented from running until MANUAL OVERRIDE key pressed. Anti-recycle timers set to default to allow time to check settings. Replace battery as soon as possible. | 180 |
| UNIT WARNING: INVALID NUMBER OF COMPRESSSORS SELECTED | No or multiple "Number of Compressors Select" jumpers installed | No jumpers installed or more than 1 jumper installed in the VSD wiring harness at power-up | Turn off both control panel and VSD control voltage. Install proper jumpers in the VSD wiring harness (see Page 136). | 183 |
| UNIT WARNING: INVALID SERIAL NUMBER ENTER UNIT SERIAL NUMBER | Chiller serial number not programmed or lost | Chiller Control Board replaced, EPROM changed, or factory programming lost | Contact YORK Product Technical Support immediately. Serial number entered using Service Key with factory password. Optimized IPLV chiller will only run in Standard IPLV mode until serial number is programmed. | 183 |
| UNIT WARNING: OPTIMIZED EFFICIENCY DISABLED - CONTACT YORK REPRESENATIVE | Optimized chiller programmed for standard control | High IPLV mode not enabled — serial number not programmed or option not activated | Contact YORK Product Technical Support or YORK ES Commercial. Special password required to enable optimized IPLV control via Service Key. | 183 |
UNIT SAFETIES
| Code / display | Meaning | Cause | Action | Page |
|---|---|---|---|---|
| UNIT YYYYYYYY LOW AMBIENT TEMP | Ambient temperature below programmable low ambient cutout | Ambient temperature fell below the programmable Low Ambient Temp Cutout (only if enabled under OPTIONS key) | Controlled ramped shutdown. Auto-restart when temperature rises 2°F above cutout. Cannot cause lockout. Unit inhibited from starting when temperature below cutout + 2°F. | 184 |
| UNIT YYYYYYYY LOW LEAVING CHILLED LIQUID TEMP | Leaving chilled liquid temperature below freeze protection cutout | Leaving chilled liquid temperature dropped below the programmable cutout point (low flow conditions or improperly programmed setpoint values) | Controlled ramped shutdown. Auto-restart when chilled liquid temperature rises 4°F above cutout. Cannot cause lockout. Unit inhibited from starting when temperature below cutout + 4°F. | 185 |
| UNIT YYYYYYY VSD COMMUNICATIONS FAILURE | Chiller Control Board lost or never established communications with VSD Logic Board | No valid response received for 8 seconds during operation, or initialization data not received at power-up | Controlled ramped shutdown. Unit inhibited from starting until communications established. Automatically resets when Chiller Control Board receives a valid response from the VSD. | 185 |
SYSTEM SAFETIES (FAULTS)
| Code / display | Meaning | Cause | Action | Page |
|---|---|---|---|---|
| SYS X YYYYYYYY HIGH DISCHARGE PRESSURE | Discharge pressure rose above software cutout threshold | Discharge pressure rose above 274 PSIG for 0.5 seconds | Controlled ramped shutdown. Restart allowed when discharge pressure falls to 259 PSIG. Inhibited from starting if pressure above 259 PSIG. Auto-restart after 120 second anti-recycle timer. Locks out after 3 faults in 90 minutes. | 186 |
| SYS X YYYYYY HPCO FAULT | Mechanical high pressure cutout contacts opened | Mechanical high pressure cutout opened at 297+/-8 PSIG | Immediate shutdown. Auto-restart after 120 second anti-recycle timer. Locks out after 3 faults in 90 minutes. HPCO resets (closes) at 230+/-10 PSIG. | 187 |
| SYS X YYYYYYYY LOW SUCTION PRESSURE | Suction pressure fell below programmable cutout | Suction pressure fell below the programmable cutout (typically 24 PSIG for chilled water applications); low refrigerant charge or low flow | Controlled ramped shutdown. Cutout ignored for first 30 seconds of run time; linearly ramped from 10% of cutout up to full value over next 3 minutes. Transient override provides additional 30-second grace period after 3.5 minutes. Auto-restart after 120 second anti-recycle timer. Locks out after 3 faults in 90 minutes. | 187 |
| SYS X YYYYYYYY LOW MOTOR CURRENT | Absence of motor current detected (<10%FLA) | Microprocessor detected motor current below 10%FLA, usually indicating compressor is not running | Controlled ramped shutdown. Safety ignored for first 10 seconds of operation. Auto-restart after 120 second anti-recycle timer. Locks out after 3 faults in 90 minutes. | 187 |
| SYS X YYYYYYYY HIGH DIFF OIL PRESSURE | Discharge-to-oil differential pressure rose above cutout | Discharge to Oil Differential Pressure rose above the cutout of 65 PSID (possibly dirty oil filter) | Controlled ramped shutdown. Safety ignored for first 90 seconds of run time. Auto-restart after 120 second anti-recycle timer. Locks out after 3 faults in 90 minutes. | 188 |
| SYS X YYYYYYYY LOW DIFF OIL PRESSURE | Oil-to-suction differential pressure fell below cutout | Differential between oil and suction pressure fell below the cutout (compressor not pumping sufficiently to push oil through lubrication system) | Controlled ramped shutdown. Safety ignored for first 60 seconds; cutout linearly ramped from 0 PSID to 30 PSID over 5–10 minutes based on ambient temperature. 30-second bypass below 50 Hz during rampdown. Auto-restart after 120 second anti-recycle timer. Locks out after 3 faults in 90 minutes. | 188 |
| SYS X YYYYYYYY HIGH DSCHARGE TEMP | Discharge temperature rose above cutout | Discharge temperature rose above 250°F | Controlled ramped shutdown. Inhibited from starting if discharge temperature above 200°F. Auto-restart after 120 second anti-recycle timer. Locks out after 3 faults in 90 minutes. | 188 |
| SYS X YYYYYYYY HIGH OIL TEMP | Oil temperature rose above cutout | Oil temperature rose above 225°F | Controlled ramped shutdown. Inhibited from starting if oil temperature above 175°F. Auto-restart after 120 second anti-recycle timer. Locks out after 3 faults in 90 minutes. | 189 |
| SYS X YYYYYYYY LOW SUCTION SUPERHEAT | Suction superheat fell below threshold indicating liquid floodback risk | One of: suction superheat <2.0°F with discharge superheat <15°F (run time <5 min, ramped cutout over 60 sec); suction superheat <2°F with discharge superheat <15°F for 10 sec (run time ≥5 min); suction superheat <0.5°F with discharge superheat >15°F for 60 sec (run time ≥5 min); suction superheat <5°F for 10 minutes | Controlled ramped shutdown. Ignored for first 30 seconds of operation. Auto-restart after 120 second anti-recycle timer. Locks out after 3 faults in 90 minutes. | 189 |
| SYS X YYYYYYYY LOW DISCHARGE SUPERHEAT | Discharge superheat fell below threshold indicating liquid floodback through economizer | After first 5 minutes of run time, discharge superheat fell below 10.0°F for 5 minutes | Controlled ramped shutdown. Ignored for first 5 minutes of operation. Auto-restart after 120 second anti-recycle timer. Locks out after 3 faults in 90 minutes. | 189 |
| SYS X YYYYYYYY SENSOR FAILURE: ZZZZZZZZZZZZ | Critical sensor reading out of range or not functioning properly | Critical sensor (transducer, level sensor, or motor winding temp sensor) reading out of range high or low. Possible values: SUCT PRESS, OIL PRESS, DSCH PRESS, LEVEL SENSOR, MOTOR TEMP X | Prevents system from running at start-up; faults and shuts down system while in operation if threshold exceeded. Auto-restart after 120 second anti-recycle timer. Locks out after 3 faults in 90 minutes. | 190 |
| SYS X YYYYYYYY HIGH MOTOR TEMP | Compressor motor temperature too high | Any compressor motor temperature sensor rose above 250°F | Controlled ramped shutdown. Inhibited from starting if motor temperatures above 240°F. Auto-restart after 120 second anti-recycle timer. Locks out after 3 faults in 90 minutes. | 190 |
| SYS X YYYYYYYY HIGH FLASH TANK LEVEL | Liquid level in flash tank too high | Tank level greater than 85% for 10 seconds | Controlled ramped shutdown. Safety ignored for first 15 seconds of operation. Auto-restart after 120 second anti-recycle timer. Locks out after 3 faults in 90 minutes. | 191 |
| SYS X YYYYYYYY CONTROL VOLTAGE | 115VAC control voltage to one system missing | System fuse removed or blown, causing loss of 115VAC supply to the affected system | Immediate shutdown of affected system. Does not cause lockout. Resets automatically when power is returned. | 191 |
From YCAV0969, YCAV1039, YCAV1139, YCAV1169, YCAV1309, YCAV1429, YCAV1549, YCAV1649, YCAV1739, YCAV1829, YCAV1909 Style A 50 Hz Installation, Operation and Maintenance 201.21-NM4
Original: docs.johnsoncontrols.com
VSD Safeties (Faults)
| Code / display | Meaning | Cause | Action | Page |
|---|---|---|---|---|
| UNIT YYYYYYYY PRECHARGE - LOW DC BUS VOLTAGE SYS X YYYYYYYY PRECHARGE - LOW DC BUS VOLT | Software-generated VSD fault detected during DC bus pre-charge. First message is a unit fault (2 or 3 compressor chillers); second is a system 1/3 or 2/4 fault on 4-compressor units. YYYYYYY indicates the system/unit is in a "FAULT" condition and will restart when the fault clears, or "LOCKOUT". | The DC bus voltage must reach at least 50 VDC within four seconds and 500 VDC within 19 seconds after the pre-charge signal has been asserted. If not, the unit/system shuts down on a fault. | Auto-restart safety; locks out on the 3rd fault in 90 minutes. On lockout, will not restart until the operator clears the fault using the keypad. | 203 |
| UNIT YYYYYYYY PRECHARGE - DC BUS VOLTAGE IMBALANCE SYS X YYYYYYYY PRECHARGE-BUS VOLT IMBAL | Software-generated VSD fault detected during the pre-charge interval. Unit fault for 3-compressor units; system 1/3 or 2/4 fault for 4-compressor units (two presses of the STATUS key required to show the fault on both systems). YYYYYYY indicates a "LOCKOUT" condition. | The 1/2 DC bus voltage magnitude must remain within +/- 100VDC of the total DC bus voltage divided by two during the pre-charge interval. If not, the unit/system shuts down on a fault. | Locks out on the 1st fault; will not restart until the operator clears the fault using the keypad. | 203 |
| UNIT YYYYYYYY HIGH DC BUS VOLTAGE SYS X YYYYYYYY HIGH DC BUS VOLTAGE | Hardware-generated VSD fault. Unit fault for 3-compressor units; system 1/3 or 2/4 fault on 4-compressor units (two STATUS key presses required to show the fault on both systems). YYYYYYY indicates a "FAULT" condition (restarts when cleared) or "LOCKOUT". | Trip level is determined by hardware on the VSD Logic Board and is designed to trip the unit at 766 +/- 30 VDC. If the DC bus exceeds this level, the unit/system faults and shuts down immediately. | Auto-restart safety; locks out on the 3rd fault in 90 minutes. On lockout, will not restart until the operator clears the fault using the keypad. | 203 |
| UNIT YYYYYYYY LOW DC BUS VOLTAGE SYS X YYYYYYYY LOW DC BUS VOLTAGE | Software-generated VSD fault. Unit fault for 3-compressor units; system fault (1/3 or 2/4) on 4-compressor units (two STATUS key presses required to show the fault on both systems). YYYYYYY indicates a "FAULT" condition (restarts when cleared) or "LOCKOUT". | The low DC bus voltage trip level is set at 500 VDC. If the DC bus drops below this level the unit/system faults and immediately shuts down. | Auto-restart safety; locks out on the 3rd fault in 90 minutes. On lockout, will not restart until the operator clears the fault using the keypad. | 204 |
| UNIT YYYYYYYY DC BUS VOLTAGE IMBALANCE SYS X YYYYYYYY DC BUS VOLTAGE IMBALANCE | Software-generated VSD fault. Unit fault for 3-compressor units; system 1/3 or 2/4 fault on 4-compressor units (two STATUS key presses required to show the fault on both systems). YYYYYYY indicates a "LOCKOUT" condition. | The 1/2 DC bus voltage magnitude must remain within +/- 100 VDC of the total DC bus voltage divided by two. If the 1/2 DC bus magnitude exceeds the +/- 100 VDC tolerances, the unit/system faults and immediately shuts down. | Locks out on the 1st fault; will not restart until the operator clears the fault using the keypad. | 204 |
| SYS X YYYYYYYY HIGH MOTOR CURRENT | Hardware-generated VSD fault; individual system/compressor fault for all units. YYYYYYY indicates a "FAULT" condition (restarts) or "LOCKOUT". | The three output lines to each phase of the compressor motor are monitored via three current transformers; instantaneous output current is compared to a predetermined hardware limit. Nominal peak current trip level is 575.5 Amps (554A min., 597A max.); 380V AC, 60Hz and 400V AC, 50Hz nominal peak current trip level is 649.5 Amps (626 Amps min., 674 Amps max.). Variation in trip point results from component tolerances on the VSD Logic Board. If the peak current limit is exceeded, the unit faults and shuts down immediately. | Auto-restart safety; locks out system on the 3rd fault in 90 minutes. On lockout, will not restart until the operator clears the fault using the keypad. | 204 |
| SYS X YYYYYYYY MOTOR CURRENT OVERLOAD | Software-generated VSD fault; individual system/compressor fault for all systems, shutting down with a controlled ramped shutdown. YYYYYYY indicates a "LOCKOUT" condition. | Compares the highest of the 3 phases of motor current per compressor to the compressor's 105 % FLA ADJUST (overload) potentiometer setting on the VSD Logic Board. If the current exceeds the setting continuously for 20 seconds, the compressor trips. | Locks out a system on the 1st fault; will not restart until the operator clears the fault using the keypad. | 205 |
| UNIT YYYYYYYY MOTOR CURRENT OVERLOAD | Hardware-generated VSD fault; unit fault that locks out all systems on the first fault. YYYYYYY indicates the unit is in a "Lockout" condition. | Compares the highest of the 3 phases of motor current per compressor to the compressor's overload ADJUST potentiometer setting. If the current exceeds the setting continuously for 30 seconds, all compressors fault and shut down immediately. | Locks out all systems on the first fault; will not restart until the operator clears the fault using the keypad. | 205 |
| SYS X YYYYYYYY GATE DRIVER | Hardware-generated VSD fault; system fault for all units. YYYYYYY indicates a "FAULT" condition (restarts) or "LOCKOUT". | Each phase bank assembly contains one IGBT gate driver control board per compressor, monitoring the saturation voltage drop across each of the six IGBTs while gated on. If the IGBT's saturation voltage exceeds the prescribed limit, the gate driver determines a short circuit is present, immediately turns off all IGBTs in the module and the system shuts down immediately. The same fault is generated if the IGBT Gate Driver board's power supply voltage falls below the permissible limit. | Auto-restart safety; locks out on the 3rd fault in 90 minutes. On lockout, will not restart until the operator clears the fault using the keypad. | 205 |
| SYS X YYYYYYYY HIGH VSD BASEPLATE TEMP | Software-generated VSD fault; system fault for all units. 3-compressor chillers operate at higher baseplate temperature compared to 4-compressor chillers. YYYYYYY indicates a "FAULT" condition (restarts when cleared) or "LOCKOUT". | Each compressor's inverter power module contains an internal temperature sensor (5K ohm at 25 Deg. °C) monitoring baseplate temperature. On 3-compressor chillers, baseplate temperatures on compressors 1 and 3 are OR'd together and the highest compared in software to a limit of 232°F; compressor #2's individual power module sensor is compared to a limit of 232°F. On 4-compressor chillers, baseplate temperatures on compressors 1 and 3 are OR'd together and compressors 2 and 4 are OR'd together, each compared in software to a limit of 218°F. If the limit is exceeded by either input, the unit faults and shuts down with a controlled ramped shutdown. | Auto-restart safety; locks out on the 3rd fault in 90 minutes. After a fault, the fan(s) and water pump remain energized until the inverter power module base plate temperature(s) falls below 165°F; the system is allowed to restart when the base plate temperatures drop below this value. On lockout, will not restart until the operator clears the fault using the keypad. | 206 |
| UNIT YYYYYYYY HIGH VSD INTERNAL AMBIENT TEMP | Software-generated VSD fault; unit fault for all units. YYYYYYY indicates the unit is in a "Fault" condition and will restart when the condition clears. | The VSD Logic Board contains a temperature sensor monitoring the unit's internal ambient temperature. If the VSD internal ambient temperature rises above the cutout of 158°F, the unit faults and shuts down with a controlled ramped shutdown. | This safety will not cause a lockout. The unit will be allowed to restart when the internal ambient temperature drops 10°F below the cutout. | 206 |
| UNIT YYYYYYYY SINGLE PHASE INPUT VOLTAGE SYS X YYYYYYYY SINGLE PHASE INPUT VOLTS | Hardware-generated VSD fault. Unit fault for 3-compressor units; system fault 1/3 or 2/4 for 4-compressor units (two STATUS key presses required to show the fault on both systems). YYYYYYY indicates the system is "FAULT" and will restart when the single phase condition clears. | The VSD's SCR Trigger Control board contains circuitry that checks the three phase mains for the presence of all three-line voltages. If any of the line voltages are not present, the system immediately shuts down on a fault. | This fault will not cause a lockout; restarts when the single phase condition clears. | 206 |
| UNIT YYYYYYYY VSD LOGIC BOARD POWER SUPPLY | Hardware-generated VSD fault; unit fault for all units. YYYYYYY indicates a "FAULT" condition (restarts when cleared) or "LOCKOUT". | Various DC power supplies which power the VSD Logic Board are monitored via hardware located on the logic board. If any of these power supplies fall outside their allowable limits, the unit immediately shuts down on a fault. | Auto-restart safety; restarts after the fault clears and locks out on the 3rd fault in 90 minutes. On lockout, cleared using the keypad. | 207 |
| SYS X YYYYYYYY VSD RUN RELAY | Software-generated VSD fault; combined as a 1/3 or 2/4 system fault. YYYYYYY indicates a "FAULT" condition (restarts when cleared) or "LOCKOUT". | Upon receipt of either of the two types of run commands (hardware and software) a 5 second timer commences timing. The hardware run signal comes from the SYS X VSD Run Signal to the VSD Logic Board; the software run signal comes through the comms from the Chiller Control Board. If the missing run signal is not asserted within the 5-second window, the system faults. In addition, if either run signal is disabled while the VSD is running, the remaining run signal must be disabled within 5 seconds after the VSD is shut down or the system faults. If running, the unit faults and shuts down with a controlled ramped shutdown. | Auto-restart safety; will autostart after the 120 second anti-recycle timer times out and locks out on the 3rd fault in 90 minutes. On lockout, will not restart until the operator clears the fault using the keypad. | 207 |
| UNIT YYYYYYYY VSD LOGIC BOARD FAILURE | Software-generated VSD fault; unit fault for all units. YYYYYYY indicates a "FAULT" condition (restarts) or "LOCKOUT". | Upon receipt of the voltage and frequency commands, the PWM generator must acknowledge receipt of the command. If the system microprocessor does not receive the handshake within 1.5 seconds of issuing the command, the unit trips. This safety is only active during precharge and during running of a compressor; it is not active when all compressors are shut down and the precharge is disabled. If the fault occurs while the chiller is running, all systems immediately shut down on a fault. | Auto-restart safety; auto restarts after the 120 second anti-recycle timer times out and locks out on the 3rd fault in 90 minutes. On lockout, cleared using the keypad. | 207 |
| UNIT YYYYYYYY VSD CT PLUG FAULT | Hardware-generated VSD fault; unit fault for all units. YYYYYYY indicates a "FAULT" condition (restarts) or "LOCKOUT". | Jumpers are installed in each CT plug on the VSD Logic Board to feed back signals indicating if the plugs are installed or not. If either plug is not installed, a low value is read on the digital input and the unit will immediately shut down on a fault or will not run if off. | Auto-restart safety; restarts after the 120 second anti-recycle timer times out and locks out on the 3rd fault in 90 minutes. On lockout, cleared using the keypad. | 207 |
Unit Warnings
| Code / display | Meaning | Cause | Action | Page |
|---|---|---|---|---|
| UNIT WARNING: !! LOW BATTERY !! CHECK SETPOINTS/PROGRAM/OPTIONS/TIME | Warning displayed indefinitely at micropanel power-up when the RTC battery voltage is determined to be low. Warnings are not logged to the history buffer. | On micropanel power-up, the RTC battery is checked to see if it is still operational. If the battery voltage is determined to be low, the warning message is displayed indefinitely. If a low battery condition exists, all programmed setpoints, program values, time, schedule, and history buffers will have been lost and reset to their default values, which may not be the desired operating values. | Once a bad battery is detected, the unit is prevented from running until the MANUAL OVERRIDE key is pressed. Once the MANUAL OVERRIDE key is pressed, the anti-recycle timers are set to the programmed default anti-recycle time to allow the operator sufficient time to check setpoints, program values, etc. If a low battery is detected, it should be replaced as soon as possible; the programmed values will all be lost and the unit will be prevented from running on the next power interruption. | 210 |
| UNIT WARNING: INVALID NUMBER OF COMPRESSORS SELECTED | Warning displayed indefinitely after the VSD has been initialized. | Occurs if no "Number of Compressors Select" jumpers are installed or if more than 1 jumper is installed. | To clear this warning, both the control panel and VSD control voltage must be turned off and the jumpers properly installed in the VSD wiring harness. These jumpers are factory installed in the wire harness plug and should not require changes. | 213 |
| UNIT WARNING: INVALID SERIAL NUMBER ENTER UNIT SERIAL NUMBER | Warning indicating the chiller may have lost important factory programmed information; when displayed, an Optimized IPLV chiller will only run in Standard IPLV control mode. | The appearance of this message may mean the chiller has lost important factory programmed information. | Immediately contact YORK Product Technical Support. The serial number can be entered using the Service Key. Optimized IPLV cannot be enabled unless the serial number is programmed into the unit using the special password supplied by YORK Product Technical Support; once the password is entered, a second password is needed to activate the optimized IPLV control. This status message can be bypassed to view additional messages under the STATUS key by pressing the STATUS key repeatedly. | 213 |
| UNIT WARNING: OPTIMIZED EFFICIENCY DISABLED - CONTACT YORK REPRESENTATIVE | Warning that an optimized chiller is programmed for standard control. | The appearance of this message means an optimized chiller is programmed for standard control. | Immediately contact YORK Product Technical Support or YORK ES Commercial. Optimized IPLV cannot be enabled unless a special password is entered; once the password is entered and the option is enabled using the Service Key, the message will disappear. This status message can be bypassed to view additional messages under the STATUS key by pressing the STATUS key repeatedly. | 213 |
Unit Safeties
| Code / display | Meaning | Cause | Action | Page |
|---|---|---|---|---|
| UNIT YYYYYYYY LOW AMBIENT TEMP | Unit safety; shuts down all running compressors with a controlled ramped shutdown. Cannot cause a lockout. | The ambient temperature falls below the programmable Low Ambient Temp Cutout. This fault only occurs if the Low Ambient Cutout is "ENABLED" under the OPTIONS key. | Restart can occur, if demand allows, when temperature rises 2°F above the cutout. The fault display message is present only during the time the ambient temperature is causing a fault condition. The unit is also inhibited from starting any time the temperature is below the cutout + 2°F. | 214 |
| UNIT YYYYYYYY LOW LEAVING CHILLED LIQUID TEMP | Unit safety helping to protect the chiller from an evaporator freeze-up should the chilled liquid temp drop below the freeze point. Cannot cause a lockout. | Any time the leaving chilled liquid temperature (water or brine) drops below the programmable cutout point. This situation could occur under low flow conditions or if the micro panel setpoint values are improperly programmed. | Shutdown with a controlled ramped shutdown. Restart can occur, if demand allows, when chilled liquid temperature rises 4°F above the cutout. The unit is inhibited from starting any time the chilled liquid temperature is below the cutout + 4°F. | 215 |
| UNIT YYYYYYYY VSD COMMUNICATIONS FAILURE | Unit safety to prevent the unit from trying to run if the Chiller Control Board never initializes communications with the VSD Logic Board. | On power-up, the Chiller Microprocessor Board attempts to initialize communications with the VSD Logic Board, requesting the number of compressors and the VSD software version; if the comms connection fails to occur, the Chiller Control Board prevents the chiller from operating. During normal operation, if the Chiller Control Board receives no valid response to messages for 8 seconds, the unit shuts down all compressors on a Comms fault. | Unit shut down with a controlled ramped shutdown; inhibited from starting until communications is established. The Chiller Control Board continues to send messages to the VSD while faulted. The fault automatically resets when the Chiller Control Board receives a valid response from the VSD for a data request. | 215 |
System Safeties (Faults)
| Code / display | Meaning | Cause | Action | Page |
|---|---|---|---|---|
| SYS X YYYYYYYY HIGH DISCHARGE PRESSURE | Software system safety; the system faults and shuts down with a controlled ramped shutdown. YYYYYYY indicates a "FAULT" condition (restarts after the 120 second anti-recycle timer times out) or "LOCKOUT". | The discharge pressure rises above 274 PSIG for 0.5 seconds. | The system is allowed to restart when the discharge pressure falls to 259 PSIG; the system is also inhibited from starting if the pressure is above 259 PSIG. On lockout, will not restart until the operator clears the fault using the keypad. | 216 |
| SYS X YYYYYYYY HPCO FAULT | Mechanical high pressure cutout protecting the system from experiencing dangerously high discharge pressure; hardware fault that occurs immediately and does not wait the 3 seconds typical of most system faults. YYYYYYY indicates a "FAULT" condition or "LOCKOUT". | The mechanical high pressure cutout contacts open. The HPCO is wired in series with the VSD Run Signal and will only be checked by the Chiller Control Board when the system is running. The mechanical cutout opens at 297+/-8 PSIG and closes at 230 +/-10 PSIG. | Immediate fault and shutdown. Restart when the 120 second anti-recycle timer times out; on lockout, will not restart until the operator clears the fault using the keypad. | 217 |
| SYS X YYYYYYYY LOW SUCTION PRESSURE | Programmable cutout serving as a secondary back-up for the flow switch; protects against operation with low refrigerant charge, helping protect the chiller from an evaporator freeze-up. YYYYYYY indicates a "FAULT" condition or "LOCKOUT". | Suction pressure falls below the programmable cutout (typically set at 24 PSIG for chilled water applications). The cutout is ignored for the first 30 seconds of system run time; during the next 3 minutes of run time the cutout point is linearly ramped from 10% of the cutout value up to the programmed cutout point (Cutout = ((Programmed Cutout x Run Time) / 200) – 1.2 PSIG). After the first 3 minutes 30 seconds of run time, if the suction pressure falls below the cutout as a result of a transient, a 30 second transient timer is set with a linearly ramped cutout starting at 10% of the programmed cutout; if over the next 30 seconds the suction pressure does not stay above the ramped cutout, the system faults. | Controlled ramped shutdown. Restart when the 120 second anti-recycle timer times out; on lockout, will not restart until the operator clears the fault using the keypad. | 217 |
| SYS X YYYYYYYY LOW MOTOR CURRENT | Shuts the system down when the microprocessor detects the absence of motor current, usually indicating that a compressor is not running. YYYYYYY indicates a "FAULT" condition or "LOCKOUT". | Motor current below 10%FLA. This safety is ignored for the first 10 seconds of operation. | Controlled ramped shutdown. Restart when the 120 second anti-recycle timer times out; on lockout, will not restart until the operator clears the fault using the keypad. | 217 |
| SYS X YYYYYYYY HIGH DIFF OIL PRESSURE | Protects the compressor from low oil flow and insufficient lubrication, possibly from a dirty oil filter. YYYYYYY indicates a "FAULT" condition or "LOCKOUT". | Discharge to Oil Differential Pressure rises above the cutout of 65 PSID. This safety measures the pressure differential between discharge and oil pressure, which is the pressure drop across the oil filter. The safety is ignored for the first 90 seconds of run time. | Controlled ramped shutdown. Restart when the 120 second anti-recycle timer times out; on lockout, will not restart until the operator clears the fault using the keypad. | 218 |
| SYS X YYYYYYYY LOW DIFF OIL PRESSURE | Protects the compressor from low oil flow and insufficient lubrication; assures the compressor is pumping sufficiently to push oil through the oil cooling circuit and the internal compressor lubrication system. YYYYYYY indicates a "FAULT" condition or "LOCKOUT". | Differential between oil and suction pressure falls below the cutout. The safety is ignored for the first 60 seconds of run time; after the first 60 seconds of operation, the cutout is linearly ramped from 0 PSID to 30 PSID in 5 to 10 minutes based on ambient temperature (>50°F: 5 minutes; >45°F: 6 minutes; >40°F: 7 minutes; >35°F: 8 minutes; >30°F: 9 minutes; >=30°F: 10 minutes). A 30 second safety bypass below 50 Hertz is employed during rampdown so compressors being ramped down to 5 Hertz to add an additional compressor do not trip on a nuisance low oil differential fault. | Controlled ramped shutdown. Restart when the 120 second anti-recycle timer times out; on lockout, will not restart until the operator clears the fault using the keypad. | 218 |
| SYS X YYYYYYYY HIGH DISCHARGE TEMP | Protects the motor and compressor from overheating. YYYYYYY indicates a "FAULT" condition or "LOCKOUT". | Discharge Temperature rises above 250°F. The system is also inhibited from starting if the discharge temperature is above 200°F. | Controlled ramped shutdown. Restart when the 120 second anti-recycle timer times out; on lockout, will not restart until the operator clears the fault using the keypad. | 218 |
| SYS X YYYYYYYY HIGH OIL TEMP | Protects the compressor from insufficient lubrication. YYYYYYY indicates a "FAULT" condition (restarts when the fault clears) or "LOCKOUT". | Oil temperature rises above 225°F. The system is inhibited from starting if the oil temperature is above 175°F. | Controlled ramped shutdown. Restart when the fault clears; on lockout, will not restart until the operator clears the fault using the keypad. | 219 |
| SYS X YYYYYYYY LOW SUCTION SUPERHEAT | Helps protect the compressor from liquid floodback due to low suction superheat. YYYYYYY indicates a "FAULT" condition or "LOCKOUT". | Ignored for the first 30 seconds of compressor operation. Faults when any one of the following occur: after the first 30 seconds of run time, if the suction superheat falls below 2.0°F, the discharge superheat is < 15°F, and the run time is < 5 minutes, the superheat safety is ignored for the next 30 seconds, then the superheat cutout is set to 0°F and linearly ramped up to 2.0°F over the next 60 seconds (fault if the suction superheat falls below the ramped cutout during these 60 seconds); or suction superheat < 2°F and discharge superheat < 15°F for 10 seconds with run time = or > 5 minutes; or suction superheat < 0.5°F and discharge superheat > 15°F for 60 seconds with run time = or > 5 minutes; or suction superheat < 5°F for 10 minutes. | Controlled ramped shutdown. Restart after the 120 second anti-recycle timer times out; on lockout, will not restart until the operator clears the fault. | 219 |
| SYS X YYYYYYYY LOW DISCHARGE SUPERHEAT | Helps protect the compressor primarily from liquid floodback through the economizer line due to a high flash tank level; also provides protection from liquid floodback through the suction line in conjunction with the low superheat safety. YYYYYYY indicates a "FAULT" condition or "LOCKOUT". | Ignored for the first 5 minutes of compressor operation. After the first 5 minutes of run time, if the discharge superheat falls below 10.0°F for 5 minutes, the system faults. | Controlled ramped shutdown. Restart when the 120 second anti-recycle timer times out; on lockout, will not restart until the operator clears the fault using the keypad. | 219 |
| SYS X YYYYYYYY SENSOR FAILURE: ZZZZZZZZZZZZ | Prevents the system from running when a critical sensor (transducer, level sensor, or motor winding temp sensor) is not functioning properly and reading out of range. ZZZZZZZZZZZZ indicates the failed sensor: SUCT PRESS, OIL PRESS, DSCH PRESS, LEVEL SENSOR, or MOTOR TEMP X. YYYYYYY indicates a "FAULT" condition (restarts when the fault clears) or "LOCKOUT" after 3 faults. | Checked at start-up and will prevent the system from running if one of the sensors has failed; also faults and shuts down a system while in operation if a safety threshold is exceeded or a sensor reads out of range (high or low). Start inhibit sensor thresholds: suction transducer 0.3–4.7 VDC; oil transducer 0.3–4.7 VDC; discharge transducer 0.3–4.7 VDC; level sensor 3.0–21.0 mA; motor temp. sensor 0–240°F. | At start-up the system is prevented from running; in operation the system faults and shuts down. Restart when the fault clears; on lockout (after 3 faults), will not restart until the operator clears the fault using the keypad. The Unit Setup Mode allows a specific motor temperature sensor to be ignored if it fails. | 220 |
| SYS X YYYYYYYY HIGH MOTOR TEMP | Prevents a compressor from running when its motor temperature is too high. YYYYYYY indicates a "FAULT" condition (restarts when the fault clears) or "LOCKOUT". | Any compressor motor temperature sensor rises above 250°F. The system is inhibited from starting if its motor temperature sensors indicate temperatures above 240°F. If any single temperature sensor is being ignored under the Unit Set-up Mode, that sensor is not utilized when evaluating motor temperature. | Fault and shutdown. Restart when the fault clears; on lockout, will not restart until the operator clears the fault using the keypad. | 220 |
| SYS X YYYYYYYY HIGH FLASH TANK LEVEL | Prevents the system from running when the liquid level in the flash tank is too high. YYYYYYY indicates a "FAULT" condition or "LOCKOUT". | The safety is ignored for the first 15 seconds of system operation. A fault occurs if the tank level is greater than 85% for 10 seconds. | Restart when the 120 second anti-recycle timer times out; on lockout, will not restart until the operator clears the fault using the keypad. | 221 |
| SYS X YYYYYYYY CONTROL VOLTAGE | Alerts the operator that the 115V AC Control voltage to one of the systems is missing. YYYYYYY indicates a "FAULT" condition (restarts when the fault clears). | The 115V AC Control voltage to one of the systems is missing; this could be due to a system fuse that has been removed or is blown. The affected system faults and shuts down immediately when the 115V AC supply is lost. The safety will not shut down a system if the Unit Switch is OFF (which electrically removes the 115V AC to all systems); it is only used to indicate a situation where a single system is missing the 115V AC. | The safety will not cause a lockout; the system fault resets when power is returned. | 221 |
Flash Card Update Error Codes
| Code / display | Meaning | Cause | Action | Page |
|---|---|---|---|---|
| FLASH CARD UPDATE ERROR 10 | Error message displayed if an error occurs during the flash card program update; XXXXX is the Error Code. | Flash card not found. | 212 | |
| FLASH CARD UPDATE ERROR 11 | Error message displayed if an error occurs during the flash card program update; XXXXX is the Error Code. | SOFTWARE.BIN file not found. | 212 | |
| FLASH CARD UPDATE ERROR 14 | Error message displayed if an error occurs during the flash card program update; XXXXX is the Error Code. | SOFTWARE.BIN file larger than expected. | 212 | |
| FLASH CARD UPDATE ERROR 15 | Error message displayed if an error occurs during the flash card program update; XXXXX is the Error Code. | RAM to IPU Flash transfer of DATABASE.BIN failed. | 212 | |
| FLASH CARD UPDATE ERROR 16 | Error message displayed if an error occurs during the flash card program update; XXXXX is the Error Code. | RAM to IPU Flash transfer of SOFTWARE.BIN failed. | 212 | |
| FLASH CARD UPDATE ERROR 17 | Error message displayed if an error occurs during the flash card program update; XXXXX is the Error Code. | Could not allocate sufficient memory to read or write file. | 212 | |
| FLASH CARD UPDATE ERROR 99 | Error message displayed if an error occurs during the flash card program update; XXXXX is the Error Code. | Internal software error. | 212 |
From YCAV and YCIV Low Suction Pressure and High Flash Tank Fault Troubleshooting SI0219
Original: docs.johnsoncontrols.com
LOW SUCTION PRESSURE FAULTS
| Code / display | Meaning | Cause | Action | Page |
|---|---|---|---|---|
| LOW SUCTION PRESSURE FAULTS CAUSED BY LOW FLOW | Low suction pressure fault caused by evaporator flow near or below the minimum allowed. | If flow is near the minimum or below the minimum allowed in the IOM, it may be causing the low suction pressure fault. Low flow should be suspected if only a single compressor on the chiller is running "fully loaded" on a two system chiller and a resulting temperature differential greater than 8° F across the evaporator is observed; on a three compressor system, greater than 5.3° F of temperature differential with a single compressor running is suspect; on a four compressor system, greater than 4°F with only a single compressor running is suspect. | Check approximate flow across the evaporator using a flow meter or the pressure drop charts in the IOM. Running a single system on the chiller and checking the temperature differential across the evaporator (return minus leaving water temp) is also a quick means for checking for low flow, if the flow cannot be measured using a flow meter or there is doubt about the accuracy of the flow pressure drop measurement. | 2 |
| LOW SUCTION PRESSURE FAULTS CAUSED BY LOW SUBCOOLING | Low suction pressure fault caused by low refrigerant charge or non-condensables in the system. | Low refrigerant charge is often responsible for low suction pressure faults. If there is no liquid or there are bubbles consistently observed in the liquid line sight glass, the system is under charged or there are non-condensables in the system. If high subcooling is noted along with bubbles in the sight glass, there are non-condensables in the system. | Run the suspect system to full speed and check for bubbles or a loss of liquid in the liquid line sight glass. A full column of liquid should normally be observed except during transients, such as fan cycling or a rapid speed increase. Check the "liquid line subcooling"; it should normally be 7 to 12° F on a 95° F day. If needed, turn fans OFF to approximately duplicate these conditions in colder ambients. To verify correct charge, check subcooling along with verifying there are no bubbles in the sight glass. Do not weigh the charge. Always measure liquid pressure as close to the feed valve as possible on the liquid line and measure liquid line temperature as close as possible to the feed valve when checking "liquid subcooling". | 2 |
| LOW SUCTION PRESSURE FAULTS CAUSED BY AN INCORRECT TRANSDUCER OUTPUT | Low suction pressure fault caused by an incorrect suction pressure transducer output. | The suction pressure transducer output may be incorrect; the micro panel display reading will not agree with a gauge installed on the suction line (the two readings should be reasonably close). | Install a manifold gauge on the suction line and compare the micro panel display reading to the gauge. Make sure the manifold gauges are reading correctly before condemning the transducer, since gauge accuracy is very important when working with R-134A at low pressures. If there is still doubt the micro panel is reading the pressure correctly, the transducer from the suspect system can be plugged into the input of another system that is providing a correct reading. Gauge reading comparison on a properly operating system versus the panel display is also a useful means of checking gauge accuracy. | 3 |
| LOW SUCTION PRESSURE FAULTS CAUSED BY A DEFECTIVE FEED OR DRAIN VALVE | Low suction pressure fault caused by a defective feed valve or drain valve. | A defective feed valve that causes a low suction pressure fault will often be accompanied by a legitimate 0% (empty) flash tank level or very low actual flash tank level percentage resulting from lack of refrigerant flow, and the feed valve will appear to be opening appreciably more than other system(s) on the chiller. A defective drain valve will often appear to be open near the 100% point if it is defective and starving the evaporator. A low suction fault with a drain valve position near 100% and a micro panel display level indicating more than about 5% in the flash tank is often caused by a defective level sensor outputting a higher than actual level, rather than a bad drain valve. | Operate the valve in the SERVICE mode (see IOM). Assure the valve is operating by viewing the valve sight glass while running it from 0% to 100% and 100% to 0%; the valve should visibly open and close smoothly. When the test is complete, close the valve to the 0% position and recycle power to the system. On some old style valves without integral sight glasses, the only tests possible are audibly listening for valve motor operation or touching the valve to feel possible internal movement — this only assures the motor is operating and does not allow diagnosis of a valve that is sticking or uncoupled/broken from the drive motor. Always check any plugs in the wiring between the valve and valve controller as well as between the chiller microprocessor board and the valve controller, since a bad connection or corrosion on the pins will cause problems with valve operation and possibly cause the valve to lose steps. Check valve wiring after a controlled shutdown, with power off. Be aware that in almost all cases, drain and feed valves that are replaced are not defective. Contact Product Technical Support before changing a feed or drain valve. | 3 |
| LOW SUCTION PRESSURE FAULTS CAUSED BY AN INCORRECT LEVEL SENSOR OUTPUT | Low suction pressure fault caused by a level sensor reading higher than the actual flash tank level. | Level sensors that cause actual low suction pressure faults typically have a positive offset error of more than 10% based on the micro panel display percentage; normally a problem sensor will read high in comparison to the actual tank level. If the sensor reading is more than a value of 10% above the actual level percentage, there is a risk of the flash tank running out of refrigerant when discharge pressures are low or the compressor is accelerating. When the flash tank runs out of refrigerant due to level sensor error, the drain valve is unable to control superheat and suction pressure drops. In some cases, the system only goes into suction limiting and will not accelerate in speed; in other cases, it will fault on low suction pressure. | Review the history buffer: when the flash tank is empty and the evaporator is starved, the drain valve position is often near 100% (typically over 90%) at the time of the fault, and the flash tank level typically shows 5% or higher although the tank may be empty. Operate the drain and feed valves in the SERVICE mode to rule out a problem valve, wiring, or controller. With a solid column of liquid in the liquid line sight glass, run the system with enough load to open the economizer valve and obtain a level in or near the middle of the flash tank sight glass (bottom of glass = 32%, middle = 35%, top = 38%); the FEED VALVE LEVEL SETPOINT (SERVICE 2878 ENTER) can be temporarily adjusted upward (key in 45.0) to speed this up — DO NOT change any other programmed point under the password protected displays. Compare the display to the glass: the display must indicate between 25% and 45%, and less than 10% above the actual sight glass level percentage; if not within this range and low suction pressure faults occur, the level sensor should be replaced. To check for an intermittent sensor, "lightly" tap the electronics enclosure of the level sensor with the handle of a screwdriver and watch the display for a significant change; also check plugs between the level sensor and the chiller control (microprocessor) board, since a corroded or loose pin connection will cause intermittent or erratic level sensor displays. Unless the level sensor is reading a displayed level numerically more than 10% above the actual level in the sight glass, it should not be changed without contacting factory technical support. | 4 |
HIGH FLASH TANK FAULTS
| Code / display | Meaning | Cause | Action | Page |
|---|---|---|---|---|
| HIGH FLASH TANK FAULTS CAUSED BY INCORRECT LEVEL SENSOR OUTPUTS | High flash tank level fault caused by an incorrect level sensor output. | Typically, there will be no obvious level in the flash tank sight glass (bottom of glass equals 32%), while the level display will be significantly higher. Typically there will be an error of plus 15% or more in the level sensor output before a high flash tank fault occurs. High flash tank level faults are often caused by intermittent sensors that produce an output level spike that intermittently causes a fault. Erratic sensors that rapidly shift in output (display %) are often responsible for systems that exhibit both high flash tank faults and low suction pressure faults. | If an intermittent sensor is suspected, "lightly" tap the electronics enclosure of the level sensor with the handle of a screwdriver and watch the panel display for an erratic response. | 5 |
From YCAV, YCIV IPU2 Software Version V15 – Low Temp Brine Control SI0617
Original: docs.johnsoncontrols.com
Faults
| Code / display | Meaning | Cause | Action | Page |
|---|---|---|---|---|
| Low Differential Oil Pressure Cutout | Safety cutout. | Differential pressure falls below the cutout. | Software V15 adjustment to safety protocols during soft shutdown: for part numbers 031-03476-202, -210, -225, and AGR, if the VSD frequency is less than 25 Hz and soft shutdown is in progress, the safety is ignored and the VSD continues ramping the frequency at the soft shutdown rate. 30 seconds bypass time is added at the end of Soft Shutdown for this safety. | 2 |
From YCAV, YCIV Software Version V13 Low Temp Brine Control SI0541
Original: docs.johnsoncontrols.com
SYSTEM FAULTS
| Code / display | Meaning | Cause | Action | Page |
|---|---|---|---|---|
| Low Suction Superheat Fault | The Low Suction Superheat Cutout is to protect the compressor from liquid flood back due to low suction superheat. | After the first 30 seconds (60 seconds if Soft Shutdown is Enabled) of run time, if the suction superheat < 2°F and the discharge superheat < 15°F and the run time < 5 minutes, ignore the cutout for 30 seconds (60 seconds if Soft Shutdown is Enabled) and then ramp the cutout from 0°F to 2°F over the next 60 seconds (90 seconds if Soft Shutdown is Enabled). If the suction superheat falls below the ramped cutout, the system will trip. If the suction superheat < Suction Superheat Setpoint – 3°F (max of 5°F) for 10 minutes, the system will trip. |
System will trip. This safety is ignored for the first 60 seconds (120 seconds if Soft Shutdown is Enabled) of system run time unless a restart transition has occurred. If a restart transition has occurred, the timer is set according to the following table with a maximum limit of 73 seconds: If current freq > 100 Hz: Increase timer by [(current freq – 100Hz) / 30.4 Hz/sec] + 9.5 sec If current freq <= 100 Hz: Increase timer by [(current freq – 5Hz) / 10 Hz/sec] Always: Increase timer by 60 seconds (NOTE: 9.5 sec = [(100Hz – 5Hz) / 10 Hz/sec], the time it takes to ramp from 100 Hz to 5 Hz.) Low Suction Superheat fault is ignored when any of the following are true: Soft Shutdown is in process; Ramp down while the other system is performing soft shutdown is in process; 90 seconds after ramp up starts due to ramp down / up while the other system was performing a soft shutdown. |
2 |
Compressor Shutdown Control
| Code / display | Meaning | Cause | Action | Page |
|---|---|---|---|---|
| Low Ambient Temp | The Low Ambient Temp fault is changed to perform a soft ramped shutdown if soft shutdown is enabled. | Shutdown Type: Ramped when Soft Shutdown is Disabled; Soft Ramped when Soft Shutdown is Enabled. | 4 |
From YCAV/YCIV IPU2 Software Version V14 Update SI0616
Original: docs.johnsoncontrols.com
Compressor Shutdown Control
| Code / display | Meaning | Cause | Action | Page |
|---|---|---|---|---|
| High Ambient Temp | Ramped: Soft Shutdown Disabled Soft Ramped: Soft Shutdown Enabled | 2 | ||
| High Discharge Pressure | Ramped: Soft Shutdown Disabled Soft Ramped: Soft Shutdown Enabled AND Discharge Pressure Cutout < 200 PSIG | 2 | ||
| High Oil Temp | Ramped: Soft Shutdown Disabled Soft Ramped: Soft Shutdown Enabled | 2 | ||
| High Flash Tank Level | Ramped: Soft Shutdown Disabled Soft Ramped: Soft Shutdown Enabled Turn off economizer solenoid during ramp down | 2 |
Faults and Warnings
| Code / display | Meaning | Cause | Action | Page |
|---|---|---|---|---|
| High Discharge Pressure Cutout (Software) | When using software build -225 or -AGR, a system will shut down when discharge pressure rises above the programmed cutout for 0.5 seconds. | A system will be inhibited from starting when its Discharge Pressure is above the programmed cutout - 15 PSIG. | 2 |
High Oil Temperature Cutout
| Code / display | Meaning | Cause | Action | Page |
|---|---|---|---|---|
| High Oil Temperature Cutout | The High Oil Temperature Cutout fault will clear and be disabled when Oil Temp Sensor is Disabled. | 4 |
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