| Document type | Operation Guide |
|---|---|
| Document number | 160.00-O2 |
| Equipment | YK Centrifugal Chiller |
| Brand | YORK |
| File size | 2.2 MB |
Fault codes in this document
Safety shutdowns
| Code / display | Meaning | Cause | Action | Page |
|---|---|---|---|---|
| LCSSS - 105% MOTOR CURRENT OVERLOAD | The highest of the three phase RMS currents exceeds 100% FLA × 1.05 continuously for 40 seconds. | Programmed FLA incorrect on the OptiView™ control center; output CT's not reading current correctly; output current unbalanced; pre-rotation vanes or slide valve not working properly. | Safety shutdown: SCR gate outputs turn off, coastdown starts (150 seconds centrifugal / 2 minute lockout screw chillers), K1 relay de-energizes. After coastdown times out, place the Compressor Switch in Stop/Reset, then Start and release; the chiller will start if no faults are active. | 21 |
| LCSSS – HIGH PHASE X HEATSINK TEMPERATURE - RUNNING (X = A, B or C) |
Any one of the three SCR heatsink temperature sensors exceeds the 212°F shutdown threshold during a running condition. | Coolant level improper; coolant not pink or clear; coolant pump not working; heat exchanger dirty or no condenser water flow; heatsink assembly clogged. | Safety shutdown. The coolant pump continues to run until all temperatures are below 109°F. After the coastdown period, restart via Compressor Switch Stop/Reset then Start if the shutdown is no longer active. | 21 |
| LCSSS - HIGH INSTANTANEOUS CURRENT | Motor current in any phase reaches the shutdown threshold (programmed RMS starting current of 20–45% × Delta LRA, normal value 45%, converted to peak × 115%) and is maintained for one second. Current at threshold for less than one second does not trip. | Shorted SCR; motor shorted phase-to-ground or phase-to-phase; open SCR (if shutdown occurs during ramp up of the motor); open SCR gate; programmed starting current incorrect on the OptiView™ control center; output CT's not reading current correctly; open input fuse. | Safety shutdown. After the coastdown period, restart via Compressor Switch Stop/Reset then Start if the shutdown is no longer active. | 21 |
| LCSSS - OPEN SCR | Becomes active after the first 40 seconds of starter operation. Voltage across each SCR is monitored through an opto-coupler; if the signal is low for 5 consecutive seconds. | Gate drivers not operating; starting current value incorrect; motor overloaded on start (has been a problem on screw compressors); motor not connected; SCR gate open; open input fuse. | Safety shutdown. To help eliminate nuisance trips this shutdown can be disabled from the OptiView™ control center (refer to the service form for your style of chiller). After the coastdown period, restart via Compressor Switch Stop/Reset then Start if the shutdown is no longer active. | 22 |
| LCSSS – MOTOR OR STARTER-CURRENT IMBALANCE | Active after the starter has been running 45 seconds and the highest of the three motor currents exceeds 80% of programmed FLA; then any one phase of motor current exceeding 30% of the average current for 45 seconds. (Example: A=200A, B=200A, C=118A gives IAVE=173A, acceptable band 121A–225A; C at 118A shuts down.) | Input voltage to the starter abnormal; output CT's not reading current correctly; gate drive on the Logic/Trigger Board faulty. | Safety shutdown. After the coastdown period, restart via Compressor Switch Stop/Reset then Start if the shutdown is no longer active. | 22 |
| LCSSS - PHASE ROTATION | Input phase sequence wrong: when the "A" phase voltage transitions positive the "C" phase must be positive; when the "A" phase transitions negative the "B" phase must be positive. Only active during the first 30 line cycles after power is applied to the starter. | Phasing of the input power wiring incorrect. | Verify the phasing of the input power wiring. After the coastdown period, restart via Compressor Switch Stop/Reset then Start if the shutdown is no longer active. | 23 |
| LCSSS - PHASE X SHORTED SCR (X = A, B or C) |
Active any time the starter is not running. Opto-coupler output low (SCR turned on or shorted) for 5 continuous seconds, and the RMS phase voltage for that phase is approximately 90% of the selected input voltage range. If no voltage range has been selected on the OptiView™ control center, the voltage check is not performed. | One of the SCRs shorted. | Safety shutdown. To help eliminate nuisance trips this shutdown can be disabled from the OptiView™ control center (refer to the service form for your style of chiller). After the coastdown period, restart via Compressor Switch Stop/Reset then Start if the shutdown is no longer active. | 23 |
| MOTOR – PHASE ROTATION | YR chiller fault — this is not a fault of the LCSSS. The motor is turning in the wrong direction. | Motor wiring between the LCSSS and the chiller motor being reversed. | 23 |
Cycling shutdowns
| Code / display | Meaning | Cause | Action | Page |
|---|---|---|---|---|
| LCSSS - HIGH SUPPLY LINE VOLTAGE | Phase-to-phase RMS input voltage exceeds the high supply limit for the programmed voltage range (e.g., 440–480 V: 523 V stopped / 524 V running) for 20 continuous seconds. Disabled for the first 20 seconds of the starter run; disabled entirely if no voltage range is programmed. | Improper voltage range selected on the OptiView™ control center; improper line voltage applied to the starter. | Cycling shutdown: after the coastdown period (150 seconds centrifugal / 2 minute lockout screw chillers) the chiller automatically restarts if the shutdown is no longer active and the compressor switch is still in the run position. | 25 |
| LCSSS INITIALIZATION FAILED | After power is applied to the OptiView™ control center, the Micro Board fails to get a response from the Logic/Trigger Board after ten communication attempts (approximately 20 seconds after power was applied). The Micro Board continues trying to communicate even after recording the shutdown. | Communication cable between the OptiView™ control center and the Logic/Trigger Board faulty; Logic/Trigger Board failed (CR6 blinking but CR7 not blinking); if both CR6 and CR7 blink every two seconds, perform the communication loop back test. | Cycling shutdown: automatic restart after coastdown if the shutdown is no longer active and the compressor switch is still in the run position. | 25 |
| LCSSS - INVALID CURRENT SCALE SELECTION | P1 is not connected to J1, pulling the three starter-size determination inputs high. The presence of the P1/J1 connector is verified when power is applied; while disconnected, the three phase currents and kW values display as zero. Generally occurs during start-up of the chiller. | J1 connector not installed on the Logic/Trigger Board; J1 connector wiring faulty. | Cycling shutdown: automatic restart after coastdown if the shutdown is no longer active and the compressor switch is still in the run position. | 26 |
| LCSSS - Logic Board Power Supply | Indicated whenever power is applied to the LCSSS. | Possible input power problems. | Cycling shutdown: automatic restart after coastdown if the shutdown is no longer active and the compressor switch is still in the run position. | 26 |
| LCSSS - LOGIC BOARD PROCESSOR | Watchdog between the main system microprocessor and the DSP (normally communicating every 3 mSec): if the DSP does not respond after 80 attempts, a cycling shutdown occurs and the DSP is rebooted. The watchdog timer only resets if communications have been established. | If the problem continues, replace the Logic/Trigger Board. Automatic restart after coastdown if the shutdown is no longer active and the compressor switch is still in the run position. | 26 | |
| LCSSS - LOW PHASE X TEMPERATURE SENSOR (X = A, B or C) |
Any one of the three thermistors mounted on the SCR assemblies reads a value corresponding to 37°F or lower. Thermistors are connected to the Logic/Trigger Board at plugs P2, P3, P4. | Normally associated with an open thermistor; P2, P3, and P4 not connected to the Logic/Trigger Board; interconnection between the thermistor and the P2, P3, and P4 connectors faulty. | Cycling shutdown: automatic restart after coastdown if the shutdown is no longer active and the compressor switch is still in the run position. | 26 |
| LCSSS - LOW SUPPLY LINE VOLTAGE | Phase-to-phase RMS input voltage falls below the low supply limit for the programmed voltage range (e.g., 440–480 V: 400 V stopped / 370 V running) for 20 continuous seconds. Disabled for the first 20 seconds of the starter run; disabled if no voltage range is programmed. | Improper voltage range selected on the OptiView™ control center; improper line voltage applied to the starter; during generator operation, the generator responding slowly to load changes. | If the problem occurs during generator operation, add some standby load to the generator so that it can respond more quickly to load changes. Automatic restart after coastdown if the shutdown is no longer active and the compressor switch is still in the run position. | 27 |
| LCSSS - PHASE LOCKED LOOP | The error signal of the synchronization circuit becomes too large and synchronization with the 'A' phase voltage is lost; if synchronization is not maintained the SCRs will misfire and damage the chiller. | Storms or power problems causing the frequency of the 'A' phase voltage to change too rapidly; during generator operation, JP1 jumper not cut (on Rev. C or earlier Logic/Trigger Boards); during generator operation, the generator responding slowly to load changes. | If the problem occurs during generator operation, ensure the JP1 jumper has been cut (Rev. C or earlier boards) and/or add standby load to the generator. Automatic restart after coastdown if the shutdown is no longer active and the compressor switch is still in the run position. | 27 |
| LCSSS - PHASE LOSS | Any one of the three phases of input line voltage drops below the threshold value (30% of the programmed input voltage range; e.g., 60 VAC if the range is disabled, 132 VAC for 440–480 VAC). | Many times a normal fault related to a storm or lightning; one of the three phases of input voltage absent (an input fuse may be open); improper voltage range selected on the OptiView™ control center. | Cycling shutdown: automatic restart after coastdown if the shutdown is no longer active and the compressor switch is still in the run position. | 27 |
| LCSSS - POWER FAULT | Active after the first four seconds of a chiller start and after all three phases of motor current have exceeded 25% of FLA for one second; then any one phase of motor current dropping below a threshold of 10% FLA for three line cycles. Disabled just before the chiller is placed into coastdown to prevent nuisance shutdowns. | Many times a normal fault related to a storm or lightning; output CT's not reading current correctly. | Cycling shutdown: automatic restart after coastdown if the shutdown is no longer active and the compressor switch is still in the run position. | 28 |
| LCSSS - RUN SIGNAL | The hardware 115 VAC start signal (between J5-2 wire #2 and TB1-3 wire #24) and the software run signal sent through the serial communications link are not both received by the main system microprocessor within 5 seconds of each other. | 115 VAC not applied between J5-2 wire #2 and TB1-3 wire #24; solder cracks around J5 and TB-1; serial communication link cable faulty. | Cycling shutdown: automatic restart after coastdown if the shutdown is no longer active and the compressor switch is still in the run position. | 28 |
| LCSSS - SERIAL COMMUNICATIONS | Becomes active after successful completion of initialization: the Micro Board has tried to communicate ten times, or the Logic/Trigger Board has not received a transmission from the Micro Board within 20 seconds (shutdown occurs in approximately 20 seconds). Under this condition all starter information displayed on the OptiView™ control center will be zero. | Communication cable between the OptiView™ control center and the Logic/Trigger Board faulty; Logic/Trigger Board failed (CR6 blinking but CR7 not blinking); if both CR6 and CR7 blink every two seconds, perform the communication loop back test. | Cycling shutdown: automatic restart after coastdown if the shutdown is no longer active and the compressor switch is still in the run position. | 28 |
| LCSSS - STOP CONTACTS OPEN | The K1 relay contacts open and no fault is detected in the serial communications link. | J1 connector not installed on the Logic/Trigger Board or no wire installed between J1-11 and J1-12; TB1-1 and TB1-2 improperly wired; communication cable between the OptiView™ control center and the Logic/Trigger Board faulty; K1 relay not working properly (replace the Logic/Trigger Board); Logic/Trigger Board failed (CR6 blinking but CR7 not blinking); if both CR6 and CR7 blink every two seconds, perform the communication loop back test. | Cycling shutdown: automatic restart after coastdown if the shutdown is no longer active and the compressor switch is still in the run position. | 29 |
Start inhibit
| Code / display | Meaning | Cause | Action | Page |
|---|---|---|---|---|
| LCSSS - HIGH PHASE X HEATSINK TEMPERATURE – STOPPED (X = A, B or C) |
Any SCR heatsink temperature above the 110°F Start Inhibit threshold while the starter is not running prevents the chiller from starting. Not a fault condition — no events are logged into the History Log. The coolant pump continues to run as long as the Start Inhibit is active and the Remote Ready Relay contacts are open. | Normal after chiller coastdown: under normal running conditions the SCR temperature is typically greater than 110°F, so the SCRs must cool before each start or they will fail. | When the temperature of all three phases has fallen below 109°F, the coolant pump stops and the LCSSS is able to start (anti-recycle timer permitting). To shorten cool-down, the condenser water pump control (OptiView™ software C.MLM.01.04 or later on YK, C.MLM.02.01 or later on YT, C.MLM.03.01 or later on YS) keeps the condenser water pump running after coastdown while any thermistor reads above 105°F and less than one hour since the chiller was last stopped; it also turns the pump on after power restoration following a power fault under the same conditions, and turns off once all three thermistors are below 105°F. | 21 |
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