| MON 10:00 AM - LOW WATER TEMP - AUTOSTART | Cycling shutdown — leaving chilled water temperature fell 4°F (2.2°C) below the chilled liquid temperature setpoint. | LCWT decreased to a value 4°F (2.2°C) below the operator-programmed chilled liquid temperature setpoint. If the setpoint is less than 40°F (4.4°C), the chiller always shuts down at 36°F (2.2°C). If the chiller is running and the setpoint is changed, the LWT cutout is a fixed 36°F (2.2°C) for 10 minutes to eliminate nuisance trips. For brine chilling applications the LWT cutout is always 4°F (2.2°C) below the setpoint (water jumper on Micro Board removed). Probable cause: system load is less than minimum capacity. | Automatic restart when water reaches setpoint; if the setpoint is increased 4°F (2.2°C) the system will continue to run, as the LWT cutout shifts to a fixed 36°F (2.2°C) for 10 minutes. | 25 |
| MON XX:XX AM - FLOW SWITCH - AUTOSTART | Cycling shutdown — chilled liquid flow switch open. | A chilled-liquid flow switch has opened; it must open for a minimum of 2 seconds to cause a shutdown. The flow switch is checked 25 seconds into "Start Sequence Initiated" and continuously thereafter. Probable cause: lack of water flow. | Automatic restart when water flow is restored (flow switch closes). Check operation of chilled water pump. | 25 |
| MON XX:XX AM - SYSTEM CYCLING - AUTOSTART | Cycling shutdown — remote cycling command received. | A remote command (computer relay contact or manual switch) connected to the Remote/Local cycling input of the digital input board has shut down the chiller. | Automatic restart upon remote command. | 25 |
| MON XX:XX AM - MULTI UNIT CYCLING - AUTOSTART | Cycling shutdown — lead/lag sequence control. | Lead/Lag sequence control accessory has shut down the chiller (contact connected to the Multi-Unit cycling input of the Digital Input Board). | Automatic restart upon remote command. | 25 |
| MON XX:XX AM - POWER FAILURE - AUTOSTART | Cycling shutdown — utility power interruption, auto-restart configuration. | There has been a power interruption or failure. Displayed when the Micro Board is configured for AUTO-RESTART AFTER POWER FAILURE (two-pin program jumper installed on the terminals labeled "Auto R" (J60); factory setting is manual restart). | Chiller will automatically restart when power is restored. | 25 |
| MON XX:XX AM - POWER FAILURE | Cycling shutdown — utility power interruption, manual-restart configuration. | There has been a power interruption or failure. Displayed when the Micro Board is configured for MANUAL RESTART AFTER POWER FAILURE (factory setting; two-pin jumper removed from the "Auto R" (J60) terminals). | When power is restored, press the COMPRESSOR switch to STOP/RESET position and then to START position. | 25 |
| AC UNDERVOLTAGE - AUTOSTART | Cycling shutdown — compressor proved not running while Control Center in RUN mode (AC undervoltage / loss of start signal). | Control Center was in RUN mode, displaying SYSTEM RUN - LEAVING TEMP CONTROL, but motor current was less than 10% FLA for 25 continuous seconds, indicative of an AC undervoltage condition that caused the start relay (1R) to de-energize. Checked when the Control Center goes into RUN mode (after 30 second pre-lube). Can be caused by failure of any component that would cause a loss of the start signal from the Control Center. Check is not performed when program jumper JP4 is removed (Steam Turbine applications). | Autostart (automatic restart). | 25 |
| MON XX:XX AM - INTERNAL CLOCK - AUTOSTART | Cycling shutdown — daily schedule stop time reached. | The operator-programmed daily stop schedule has shut down the chiller. | Will automatically restart when the operator-programmed daily start schedule indicates a start; can be overridden by pressing the COMPRESSOR switch to the START position. | 26 |
| REMOTE STOP | Cycling shutdown — remote stop command. | A remote device (typically an Energy Management System) has commanded the chiller to shut down. Message only displayed when Control Center is in REMOTE mode. | Chiller will restart upon application of a separate start signal from the remote device. | 26 |
| MON XX:XX AM - LOW EVAP PRESSURE | Safety shutdown — low evaporator pressure. | Evaporator pressure has decreased to 25.0 psig (172 kPa) (R-134a). | Chiller allowed to start when pressure increases to 25.1 psig (173 kPa) (R-134a). Press COMPRESSOR switch to STOP/RESET position and then to START position. | 26 |
| MON XX:XX AM - LOW EVAP PRESSURE - BRINE | Safety shutdown — external brine low evaporator pressure safety tripped. | The brine Low Evaporator Pressure (LEP) safety contacts have opened. The brine LEP safety is located external to the Control Center (not included with standard Control Center); cut-out settings vary with the brine application. | Wait until the safety contacts close, then press COMPRESSOR switch to STOP/RESET position and then to START position. | 26 |
| MON XX:XX AM - OIL PUMP DRIVE - AUTOSTART | Shutdown — oil pump variable speed drive protection tripped. | Oil pump VSD internal protection circuit has initiated a drive shutdown. | Message displayed until the oil pump VSD internal protection circuit permits the drive to run (autostart). | 26 |
| MON XX:XX AM - LOW OIL PRESSURE | Safety shutdown — low differential oil pressure. | Oil pressure has decreased to 15 PSID while running, or never achieved 25 PSID before the compressor start during the oil pump pre-lube run. Differential pressure is sensed by two pressure transducers. | Chiller allowed to restart when pressure increases to 25 PSID (173 kPa). Press COMPRESSOR switch to STOP/RESET position and then to START position. | 26 |
| MON XX:XX AM - HIGH OIL FLOW | Shutdown — oil pressure outside expected band (high oil flow condition). | Oil pressure is < 35 PSID (241 kPa) for 5 continuous seconds during the last 10 seconds of the compressor pre-lube or during the first 15 seconds of SYSTEM RUN; or the oil pressure is < the programmed OIL PRESSURE SETPOINT and the speed command is at 60Hz for 5 continuous seconds anytime after the first 30 seconds of SYSTEM RUN. | | 27 |
| MON XX:XX AM - HIGH PRESSURE | Safety shutdown — high condenser pressure. | Condenser pressure has increased to 180 psig (1241 kPa) (R-134a), prompted by the opening of the High Pressure (HP) safety control contacts; HP safety control is located on a mounting bracket above the oil-pump starter located on the condenser. | System allowed to restart when pressure decreases to 120 psig (827 kPa) (R-134a). Press COMPRESSOR switch to STOP/RESET position and then to START position. | 26 |
| MON XX:XX AM - EVAP TRANS OR PROBE ERROR | Safety shutdown — evaporator transducer/probe plausibility check failed. | Leaving chilled water temperature minus evaporator saturation temperature outside the range of -2.5°F (-19°C) to +25°F (-3.9°C) continuously for 10 minutes. On brine applications (program jumper JP3 removed) this check is not performed when the evaporator transducer is reading a pressure below its "out-of-range" threshold. On Steam Turbine applications (Micro Board program jumper JP4 removed) with EPROM version C.02F(T).12 or later, this check is bypassed for the first 20 minutes of chiller run time and then performed at the regular 10 minute intervals thereafter. | Press COMPRESSOR switch to STOP/RESET position and then to START position. | 26 |
| MON XX:XX AM - MOTOR CONTROLLER - EXT. RESET | Safety shutdown — starter / drive initiated shutdown requiring external reset. | A current module (CM-2 Electro-Mechanical starter application), the YORK Solid State Starter or the Variable Speed Drive initiated a shutdown. NOTE: the Solid State Starter 110°F (43.3°C) start inhibit does not require an external reset — anytime the chiller has been shut down for any reason, this message is displayed until the SCR heatsink temperatures decrease to below 110°F (43.3°C). | Reset the external device that caused the shutdown; the chiller will then automatically restart. | 27 |
| MON XX:XX AM - POWER FAULT - AUTOSTART | Cycling shutdown — motor controller power fault. | Solid State Starter or current module (CM-2 Electro-Mechanical starter application) "Power Fault" shutdown, sensed by the motor controller input to the digital input board; initiated by the motor controller contacts (CM-1) opening and reclosing in one second (less than 3 seconds per Table 1). If Solid State Starter application, the shutdown could have been caused by: phase rotation/loss, Trigger Board out of lock (OOL), Power Fault, or Half Phase — the appropriate light on the Solid State Starter Logic Board will be illuminated. | Chiller will automatically restart (following coastdown). | 27 |
| MON XX:XX AM - HIGH DISCHARGE TEMP | Safety shutdown — high discharge temperature. | Discharge temperature has increased to 220°F (104°C); sensed by thermistor RT2. | System allowed to restart when temperature has decreased to 219°F (103°C). Press COMPRESSOR switch to STOP/RESET position and then to START position. | 27 |
| MON XX:XX AM - HIGH OIL TEMP | Safety shutdown — high oil temperature. | Oil temperature has increased to 180°F (82.2°C); sensed by thermistor RT3. | System allowed to restart when temperature decreases to 179°F (81.6°C). Press COMPRESSOR switch to STOP/RESET position and then to START position. | 27 |
| MON XX:XX AM - HIGH OIL PRESSURE | Safety shutdown — high differential oil pressure. | Oil pressure has increased to 90 PSID (620 kPa). | Chiller allowed to restart when oil pressure decreases to 59 PSID (407 kPa). Press COMPRESSOR switch to STOP/RESET position and then to START position. | 27 |
| MON XX:XX AM - FAULTY COND PRESSURE XDCR | Safety shutdown — condenser pressure transducer out of range. | Condenser transducer is indicating a pressure of less than 6.8 psig (46.8 kPa) (R-134a) or a pressure greater than 300 psig (2068 kPa) (R-134a); generally indicative of a defective condenser transducer or the transducer has been disconnected. | After the problem has been corrected, press COMPRESSOR switch to STOP/RESET position and then to START position. | 27 |
| MON XX:XX AM - FAULTY OIL PRESSURE XDCR | Safety shutdown — oil pressure transducer out of range. | Either the high side or low side oil pressure transducer was out-of-range (displaying x's) while the chiller was running. | Press COMPRESSOR switch to STOP/RESET position and then to START position. | 27 |
| VANE MOTOR SWITCH OPEN | Safety shutdown — prerotation vanes not fully closed at start. | A system-start sequence has been initiated, but the pre-rotation vanes are not fully closed. Vanes are set improperly. | Restart automatically after the vane motor linkage is set properly; reset vane linkage and check vane positions using the SERVICE key switch and proper keys on the Microcomputer Control Center, then press COMPRESSOR switch to STOP/RESET and then to START switch. | 27 |
| MON XX:XX AM - STARTER MALFUNCTION DETECTED | Safety shutdown — motor current detected while compressor-start signal de-energized. | Control Center has detected a motor-current value greater than 15% FLA for 10 seconds minimum anytime the compressor-start signal is not energized. | Press COMPRESSOR switch to STOP/RESET position and then to the START position. Check motor starter operation; motor current value greater than 15% FLA. | 27 |
| MON XX:XX AM - LOW OIL TEMP DIFF - AUTOSTART | Cycling shutdown — insufficient oil-to-condenser saturation temperature difference. | Shut down for one of the following reasons: (1) chiller shut down for 30 minutes or less and oil temperature minus condenser saturation temperature is less than 20°F (11°C); (2) chiller shut down for more than 30 minutes and oil temperature minus condenser saturation temperature is less than 30°F (16.7°C); (3) following a power failure, oil temperature minus condenser saturation temperature is less than 30°F (16.7°C). This check is made only when the chiller is shut down — not when running or in "Start Sequence Initiated". | Chiller will restart automatically after the condition clears if the COMPRESSOR switch is in the RUN position. | 29 |
| DAY - TIME - OIL PRESSURE XDCR ERROR | Shutdown — oil pressure transducer auto-zero check failed. | Difference between the High Side Oil Pressure Transducer output and the Low Side Transducer output was greater than 15.0 PSID (103 kPa) during the "Transducer Auto-Zeroing Sequence" that occurs 10 seconds after a chiller start is initiated; message displayed immediately after the auto-zeroing sequence has completed. Indicates one of the transducer outputs is incorrect, possibly due to an incorrect or defective transducer. | Press COMPRESSOR switch to STOP/RESET position and then to START position. | 29 |
| MON XX:XX AM - FAULTY DISCHARGE TEMP SENSOR | Safety shutdown — discharge temperature sensor fault. | Discharge temperature has fallen below 30°F (-1°C), or the discharge temperature sensor is disconnected from the Micro Board. Probable cause: faulty discharge temp thermistor (RT2) or thermistor disconnected from Analog Input Board. | To restart when the discharge temperature rises or the sensor has been connected, press COMPRESSOR switch to STOP/RESET position and then to START position. Connect or replace open sensor. | 29 |
| MON XX:XX AM - PROX SENSOR SAFETY SHUTDOWN | Safety shutdown — high speed thrust collar axial position out of range. | "Proximity/Temperature Sensor" detected that the distance between the compressor high speed thrust collar and the sensor probe has increased by 10 mils or more, or decreased by 20 mils or more (25 mils with EPROM version C.02F(T).12 or later) from the "Reference Position". With EPROM version C.02F(T).11, if the reference position is < 42 mils the minimum allowed distance is 22 mils; with EPROM version C.02F(T).12 or later, if the reference position is < 44 mils the minimum allowed distance is 19 mils. | LOCKOUT — cannot be restarted until a qualified service technician performs a visual inspection of the high speed thrust bearing and performs the special reset procedure detailed in YORK Service manual Form 160.49-M2. Failure to perform the visual inspection prior to restarting the chiller could result in severe compressor damage. | 29 |
| DAY - TIME - FAULTY PROXIMITY PROBE | Safety shutdown — proximity probe fault (possible compressor damage). | "Proximity/Temperature Sensor" detected that the distance between the compressor high speed thrust collar and the sensor probe has decreased to 17 mils or less. Generally indicative of a defective proximity probe, but it is possible that the compressor has been damaged. | LOCKOUT — chiller cannot be restarted until the "Special Reset Procedure" in YORK Service manual Form 160.49-M2 is performed by a qualified service technician; the high speed thrust bearing must be inspected by a qualified service technician prior to starting the chiller, or further severe compressor damage could result. | 29 |
| MON XX:XX AM - HIGH SPEED DRAIN TEMP | Safety shutdown — high speed drain line temperature. | "Proximity/Temperature Sensor" detected the temperature of the high speed drain line has reached 250°F (121°C) or greater. | LOCKOUT — cannot be restarted until a qualified service technician performs a visual inspection of the high speed thrust bearing and performs the special reset procedure detailed in YORK Service manual Form 160.49-M2. Failure to perform the visual inspection prior to restarting the chiller could result in severe compressor damage. | 29 |
| MON XX:XX AM - OPEN DRAIN TEMP THERMOCOUPLE | Safety shutdown — open thermocouple / wiring fault in high speed drain temperature circuit. | "Proximity/Temperature Sensor" thermocouple or high speed drain temperature wiring between the "Proximity/Temperature Sensor" module and the Microcomputer Control Center has been disconnected or has a poor electrical connection. | Bearing inspection is not required (open thermocouple shutdowns typically indicate hardware or wiring defects and must not result in any damage to the compressor high speed thrust bearing); however, due to the critical nature of these circuits, a special reset procedure must be performed by a qualified service technician before the chiller can be restarted (Service manual Form 160.49-M2). | 30 |
| MON XX:XX AM - DC UNDERVOLTAGE | Safety shutdown — low +24 VDC supply to the Proximity/Temperature Sensor module. | The Micro Board monitors the +24VDC supply to the "Proximity/Temperature Sensor" module (which becomes unstable in operation at +17VDC); when the supply decreases to +19VDC the chiller is shut down, preventing invalid "Proximity Sensor Safety" or "High Speed Drain Temp" safety shutdowns. | Chiller will automatically restart when the voltage increases to greater than +19.7 VDC. | 30 |
| MON XX:XX AM - AUX SAFETY SHUTDOWN | Safety shutdown — user-defined auxiliary safety input. | An external device, connected to digital input board TB 1-31 (Auxiliary Safety Shutdown Input), has initiated a system shutdown. This input is a general purpose input that can be used to annunciate a user-defined safety shutdown. | Press COMPRESSOR switch to STOP-RESET position and then to START position. | 30 |
| REPLACE RTC U16 - REPROGRAM SETPOINTS | Alarm — real-time clock battery defective. | The battery located inside the REAL-TIME CLOCK IC chip (U16 on the Micro Board) is defective; this battery provides back-up power to the RTC memory (RAM) in the event of a utility AC power failure, assuring the system setpoints are maintained. | Replace RTC IC chip U16 (order YORK part number 031-00955-000): with AC power removed, remove existing RTC chip from socket and discard; observe anti-static precautions and install new chip with orientation notch UP. If there had been a power failure while this message was displayed, the setpoints were lost and must be reprogrammed; then proceed with normal start-up. | 30 |
| MON 10:00 AM LOW LINE VOLTAGE | Cycling shutdown — AC line voltage below undervoltage threshold (Solid State Starter applications). | AC power line voltage below the LOW LINE VOLTAGE CUTOUT point for the programmed supply voltage range for 20 continuous seconds. Trip/reset values: 380V range — cutout 305V, cutin 331V; 400V — 320/349V; 415V — 335/362V; 440-480V — 370/400V; 550-600V — 460/502V; Supply Voltage Range Disabled — protection none. | Chiller automatically restarts when all phases of line voltage increase to the minimum required starting level. Overvoltage/undervoltage protection can be disabled (SUPPLY VOLTAGE RANGE DISABLED); supply voltage range is factory-programmed and may only be changed by a service technician with special access code. | 11 |
| MON 10:00AM HIGH LINE VOLTAGE | Cycling shutdown — AC line voltage above overvoltage threshold (Solid State Starter applications). | AC power line voltage above the HIGH LINE VOLTAGE CUTOUT point for the programmed supply voltage range for 20 continuous seconds. Cutout (on rise)/cutin (on fall) values: 380V range — 415/414V; 400V — 436/435V; 415V — 454/453V; 440-480V — 524/523V; 550-600V — 655/654V; Supply Voltage Range Disabled — protection none. | Protection can be disabled (SUPPLY VOLTAGE RANGE DISABLED); supply voltage range is factory-programmed and may only be changed by a service technician with special access code. | 11 |
| Program Initiated Reset | Cycling shutdown — watchdog timer reset of the software program (shutdown cause listed in Table 1). | Watchdog timer circuit has reset the software program. | Chiller will automatically restart. | 47 |
| MTR Phase Current Unbalance (SSS Units only) | Safety shutdown — motor phase current unbalance (Solid State Starter applications; shutdown cause listed in Table 1). | Motor phase current unbalance; governed by the SSS Logic Board (operating point — see legend on wiring diagram / "Section 2"). | Press STOP/START switch then START switch. | 47 |
