48
Table 36 — Alarm and Alert Codes (cont)
ALARM/ALERT
CODE
ALARM OR
ALERT
DESCRIPTION
WHY WAS THIS
ALARM GENERATED?
ACTION TAKEN
BY CONTROL
RESET METHOD
PROBABLE
CAUSE
31 Alert Circuit B Economizer 
Transducer Failure
Calibration offset more 
than 6 PSIG (41 kPa) or 
Voltage ratio (volts read/
ref. voltage) more than 
99.9% or less than 0.5%
Circuit B shut down Automatic Transducer failure, power 
supply failure, or wiring 
damage/error.
32 Alarm Transducer Supply Out-
side 4.5 to 5.5 Volts
Reference voltage mea-
sured at PSIO-1, J7-
34,35 less than 4.5 V or 
greater than 5.5 V.
Chiller shut down Automatic Power supply failure or
wiring error. Low trans-
former voltage.
34 Alert 4-20 mA Reset Input Out 
of Range
If configured and input
signal to PSIO-2,
J7-19,20(HX),
J7-22,23(GX) less than
2 mA or greater than
20mA
Reset function disabled. 
Normal set point used
Automatic Faulty signal generator, 
wiring error, 500 ohm 
resistor missing or not 
properly installed.
35 Alert 4-20 mA Demand Limit 
Input Out of Range
If configured and input
signal to PSIO-2,
J7-22,23(HX),
J7-13,14(GX) less than
2 mA or greater than
20mA
Demand limit ignored. 
Runs under normal con-
trol based on 100% 
demand limit.
Automatic Faulty signal generator, 
wiring error, 500 ohm 
resistor missing or not 
properly installed.
36 Alarm Loss of Communication 
with “Hardware Point”
PSIO-1 has lost commu-
nication with one of the 
points in Table 37.
See Table 37. Automatic Failed module, wiring 
error, failed transformer, 
loose connection plug, 
wrong address
37 Alert Circuit A Low
Saturated Suction 
Temperature
SST reads 6 F (3.3 C) or 
more below the brine 
freeze point for 3 min-
utes. For brines, SST 
may also be 14 F (7.8 C) 
or more below the lowest 
cooling set point.
Circuit A shut down Manual Low refrigerant charge, 
plugged strainer, faulty 
expansion valve. Low 
water flow.
38 Alert Circuit B Low
Saturated Suction 
Temperature
SST reads 6 F (3.3 C) or 
more below the brine 
freeze point for 3 min-
utes. For brines, SST 
may also be 14 F (7.8 C) 
or more below the lowest 
cooling set point.
Circuit B shut down Manual Low refrigerant charge, 
plugged strainer, faulty 
expansion valve. Low 
water flow.
40 Alert Compressor A1 Low Oil 
Pressure
See Note 1. Comp A1 shut down Manual Low Water Temperature, 
low refrigerant charge, 
plugged oil filter, closed 
oil valve, bad oil solenoid, 
compressor oil check 
valve stuck, oil line check 
valve stuck, plugged oil 
strainer
41 Alert Compressor A2 Low Oil 
Pressure
See Note 1. Comp A2 shut down Manual Low Water Temperature, 
low refrigerant charge, 
plugged oil filter, closed 
oil valve, bad oil solenoid, 
compressor oil check 
valve stuck, oil line check 
valve stuck, plugged oil 
strainer
42 Alert Compressor B1 Low Oil 
Pressure
See Note 1. Comp B1 shut down Manual Low Water Temperature, 
low refrigerant charge, 
plugged oil filter, closed 
oil valve, bad oil solenoid, 
compressor oil check 
valve stuck, oil line check 
valve stuck, plugged oil 
strainer
43 Alert Compressor B2 Low Oil 
Pressure
See Note 1. Comp B2 shut down Manual Low Water Temperature, 
low refrigerant charge, 
plugged oil filter, closed oil 
valve, bad oil solenoid, 
compressor oil check 
valve stuck, oil line check 
valve stuck, plugged oil 
strainer
44 Alarm Circuit A Condenser 
Freeze Protection (alarm 
ignored for brine chillers)
For W/C chillers only, if 
SCT < 34 F (1.1 C)
Chiller shut down. Turn 
Cond. pump On if Chiller 
is Off
Automatic Failed/bad discharge
pressure transducer,
refrigerant leak,
configured for water-
cooled condenser
45 Alarm Circuit B Condenser 
Freeze Protection (alarm 
ignored for brine chillers)
For W/C chillers only, if 
SCT < 34 F (1.1 C)
Chiller shut down. Turn 
Cond. pump On if Chiller 
is Off
Automatic Failed/bad discharge
pressure transducer,
refrigerant leak,
configured for water-
cooled condenser
46 Alarm Cooler Freeze
Protection
Cooler EWT or LWT less 
than freeze point. Freeze 
point is 34 F (1.1 C) for 
water, cooling set point 
minus 8 F (4.4 C) for 
brines.
Chiller shut down.
Leave Cooler pump on. 
Turn Cooler pump On if 
Chiller is Off.
Automatic** Faulty thermistor, low 
water flow