If oil pressure differential is less than set point for more than 2 minutes at
Possible causes of fault are faulty compressor, expansion valve, crankcase heater or transducer, refrigerant over- charge, insufficient oil charge, or tripped circuit breaker.
Code 42 Cooler freeze protection (alarm)
If cooler entering or leaving water temperature is below 34° F (1.1° C) for water or more than 8° F (4.4° C) below set point for brine, unit shuts down without pumpout. Chilled water pump continues to run if controlled by chiller con- trols. Reset is automatic when leaving ¯uid temperature reaches 6° F (3° C) above set point, providing there has been no prior occurrence of this fault the same day. If fault has occurred previously the same day, reset is manual with LOCAL/
Possible causes of fault are low ¯uid ¯ow or faulty thermistor.
Code 43 Low ¯uid ¯ow (alarm)
If any compressors are operating and entering ¯uid tem- perature is 3° F (1.7° C) or more below leaving ¯uid tem- perature for more than one minute, unit shuts down without pumpout. Chilled ¯uid pump also shuts down. Reset is manual with
This is a suitable method for sensing low ¯uid ¯ow be- cause entering ¯uid thermistor is in the cooler shell and re- sponds more quickly to compressor operation than the leav- ing ¯uid thermistor in the leaving water nozzle. Possible causes of fault are faulty chilled ¯uid pump, control or thermistor.
Code 44 Low cooler suction temperature, Circuit A (alert) Code 45 Low cooler suction temperature, Circuit B (alert)
If saturated suction temperature is less than 32 F (0°C) and is 20° F (11° C) for water or 30° F (16° C) for brine or more below leaving ¯uid temperature, mode 14 is dis- played. Unit continues to run, but additional compressors are not allowed to start. If condition persists for more than 10 minutes, fault code is displayed, and unit shuts down with- out pumpout. Reset is manual with
Possible causes of fault are low refrigerant charge, plugged ®lter drier, or a faulty expansion valve or thermistor.
Code 46 High suction superheat, Circuit A (alert) Code 47 High suction superheat, Circuit B (alert)
If expansion valve is fully open, suction superheat is greater than 75 F (42 C), and saturated evaporator temperature is less than MOP (maximum operating pressure) for more than 5 minutes, unit shuts down after normal pumpout process. Reset is manual with
Possible causes of fault are low refrigerant charge, plugged ®lter drier, or a faulty expansion valve or thermistor.
Code 48 Low suction superheat, Circuit A (alert) Code 49 Low suction superheat, Circuit B (alert)
If EXV is at minimum position, suction superheat is less than 10° F (5.5° C) or saturated evaporator temperature is greater than MOP (maximum operating pressure) for more than 5 minutes, affected circuit shuts down after going through pumpout process. Reset is manual with LOCAL/ENABLE-
Possible causes of fault are faulty expansion valve or thermistor.
Code 50 Illegal con®guration (alarm)
This fault indicates a con®guration error. Unit is not al- lowed to start. Check all con®guration data and set points and correct any errors.
Code 51 Initial con®guration required (alarm)
This fault indicates factory con®guration has not been done, and unit is not allowed to start. Refer to unit wiring label diagrams for factory con®guration codes. There are 9 groups of
7 groups must be entered under | subfunction. Groups |
8 and 9 must be entered under | subfunction. |
Enter each group, then press the | key. Press the |
down arrow 
after each group to bring up the next
empty screen. Unit should start after factory and ®eld con- ®gurations are correctly entered.
The usual cause of this fault is replacement of the pro- cessor module. Refer to instructions accompanying the re- placement module.
Code 52 Emergency stop by CCN command (alarm).
Unit shuts down immediately without pumpout when this command is received, and goes through normal
Code 53 Cooler pump interlock failure Ð Contacts fail to close at
If the unit is con®gured for cooler pump control and cooler pump interlock, and the interlock fails to close within one minute of starting the cooler pump, the unit is shut down without pumpout. The cooler pump is also shut down. Reset is manual with the
Possible causes are:
1.Interlock switch fails to close within one minute after chilled water pump starts
2.Interlock switch opens during unit operation
3.Interlock voltage is detected, but unit is not con®gured for interlock
4.Interlock voltage is outside its valid range
If any of these conditions occur, all compressors are dis- abled and, if running, shutdown occurs without pumpout. Chilled ¯uid pump also shuts down. Reset is manual, with
Code 54 Cooler pump interlock failure Ð Contacts open during normal operation (alarm)
If the unit is con®gured for cooler pump control and cooler pump interlock, and the interlock opens during normal op- eration, the unit is shut down without pumpout. The cooler pump is also shut down. Reset is manual with the LOCAL/
Possible causes are:
1.Interlock switch fails to close within one minute after chilled water pump starts
2.Interlock switch opens during unit operation
3.Interlock voltage is detected, but unit is not con®gured for interlock
4.Interlock voltage is outside its valid range
If any of these conditions occur, all compressors are dis- abled and, if running, shutdown occurs without pumpout. Chilled ¯uid pump also shuts down. Reset is manual, with
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