Code 30 Reset input failure (4 to 20 mA)
Code 31 Demand limit input failure (4 to 20 mA)
These codes apply only if unit is configured for these functions. If 4-20 mA signal is less than 4 or more than 20 mA, reset or demand limit function is disabled and unit functions normally. If mA signal returns to the acceptable range, function is automatically enabled.
Code 32 Loss of communication with compressor relay module (DISO-LV)
Code 33 Loss of communication with EXV relay module (DSIO-EXV)
If communication is lost with either of these modules, unit shuts down without pumpout. This alarm resets auto- matically when communication is restored. The unit starts up normally after alarm condition is reset. Probable cause of condition is a faulty or improperly connected plug, wir- ing error, or faulty module.
Loss of communication can be attributed to a grounded transformer with a secondary voltage of 21 vat supplying the PSIO, DSIO-LV, or 4 IN/4 OUT modules; the 12.5-vat transformer supplying the DSIO-EXV module; or the 24-vat transformer supplying PS 1 for the transformers. These transformers should not be grounded, or serious damage to controls can result. Check to be sure the transformers are not grounded.
NOTE: If a blank PSI0 module is downloaded without be- ing connected to the modules DSIO, this alarm is energized.
Code 34 Loss of communication with 4 In/4 Out module
This applies only if one or more of the following options are used:
0 external temperature reset
•4-20 mA temperature reset
•external switch controlled dual set point • switch controlled demand limit
• 4-20 mA demand limit
•hot gas bypass
If communication is lost with 4 IN/4 OUT module, the unit shuts off automatically, after finishing pumpout. Reset of alarm is automatic when communication is restored. Start-up after alarm is remedied follows a normal sequence. Proba- ble cause of condition is a faulty or improperly connected plug, wiring error, or faulty module.
Loss of communication can be attributed to a grounded transformer with a secondary voltage of 21 vat supplying the PSIO, DSIO-LV, or 4 IN/4 OUT; the 12.5vat trans- former supplying the DSIO-EXV module, or the 24-vat trans- former supplying PS 1 for the transformers. These transformers should not be grounded, or serious damage to controls can result. Check to be sure the transformers are not grounded.
Code 36 Low refrigerant pressure, Circuit A Code 37 Low refrigerant pressure, Circuit B
If suction pressure transducer senses a pressure below set point for more than 5 minutes at start-up or more than 2 minutes during normal operation, affected circuit shuts down without going through the pumpout process. Reset is automatic when pressure reaches 10 psig above set point if there have been no previous occurrences of this fault on the same day. If this is a repeat occurrence on same day, then reset is manual, with LOCAL/ENABLE-STOP-CCN switch, Factory configured set point is 27 psig for standard chillers and 12 psig for brine chillers.
Possible causes of fault are low refrigerant charge, faulty EXV, plugged filter drier, or faulty transducer.
Code 38 Failure to pump out, Circuit A Code 39 Failure to pump out, Circuit B
The pumpout process is terminated when saturated suc- tion temperature is 10” F (5.5” C) below temperature at be-
ginning of pumpout, or 10” F (5.5” C) below leaving water temperature or reaches a saturated suction temperature of -15 F (-26 C). If appropriate saturated suction temperature is not met within 3 minutes (on 2 consecutive tries}, circuit
shuts down without pumpout. Reset is manual with LOCAL/ ENABLE-STOP-CCN Switch, and start-up follows normal sequence.
Possible causes for this alarm are a bad thermistor or trans- ducer or a faulty EXV.
Code 40 Low oil pressure, Circuit A Code 41 Low oil pressure, Circuit B
If oil pressure differential is less than set point for more than 2 minutes at start-up, or more than one minute during normal operation, affected circuit shuts down without go-
ing through pumpout process, Reset is manual with LOCAL/ ENABLE-STOP-CCN switch, and start-up follows normal sequence. Factory configured differential oil pressure is 6 psig.
Possible causes of fault are faulty compressor, EXV, crank- case heater or transducer, refrigerant overcharge, insuffi- cient oil charge, or tripped circuit breaker.
Code 42 Cooler freeze protection
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 water 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/ENABLE-STOP-CCN switch.
Possible causes of fault are low water flow or faulty thermistor.
Code 43 Low water flow
If any compressors are operating and entering water tem- perature is 3” F (1.7” C) or more below leaving water tem- perature for more than one minute, unit shuts down without pumpout. Chilled water pump also shuts down. Reset is manual with LOCAL/ENABLE-STOP-CCN switch, and start-up follows normal sequence.
This is a suitable method for sensing low water flow be- cause entering water thermistor is in the cooler shell and responds more quickly to compressor operation than the leav- ing water thermistor in the leaving water nozzle, Possible
causes of fault are faulty chilled water pump, control or thermistor.
Code 44 Low cooler suction temperature, Circuit A Code 45 Low cooler suction temperature, Circuit B
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 fluid 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 without pumpout. Reset is manual with LOCAL/ENABLE- STOP-CCN switch, and start-up follows normal sequence.
Possible causes of fault are low refrigerant charge, plugged filter drier, or a faulty EXV or thermistor.
Code 46 High suction superheat, Circuit A Code 47 High suction superheat, Circuit B
If EXV 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 LOCAL/ENABLE-STOP-CCN switch, and start-up follows normal sequence.
