Carrier 38AU Installation, Start-Up And Service Instructions Manual page 36

Status LED Status LED Description
Green "POWER" Module has power
Red "TRIP" Thermostat demand signal
LED On Solid Y is present, but the com-
pressor is not running.
Red "TRIP" LED The anti-short cycle timer (3 minutes) in module is preventing compressor restart.
Flashing
Module locks out compressor when compressor damaging ALERT code appears.
Lockout ALERT codes are noted in the Status LED Description.
During a compressor lock out, 24VAC power must be removed from module to manually reset.
Yellow "ALERT" A short circuit or over cur-
LED On Solid rent condition exists on
PROT terminal.
Yellow "ALERT" System Pressure Trip
Flash Code 2 Discharge pressure out of
limits or compressor over-
load (if no high pressure
switch in system)
LOCKOUT
Yellow "ALERT" Short Cycling
Flash Code 3 Compressor is running only
briefly (four consecutive
cycles of less than three
minutes each)
LOCKOUT
Yellow "ALERT" Locked Rotor
Flash Code 4 LOCKOUT
Yellow "ALERT" Open Circuit
Flash Code 5
Yellow "ALERT" Missing Phase
Flash Code 6 LOCKOUT
Yellow "ALERT" Reverse Phase
Flash Code 7 LOCKOUT
Yellow "ALERT" Welded Contactor
Flash Code 8 Compressor always runs
Yellow "ALERT" Low Voltage
Flash Code 9 Control circuit < 18VAC
Table 11 – LED Status Codes
Status LED Troubleshooting Information
Supply voltage is present at module terminals
1. Compressor protector is open
2. Condensing unit power disconnect is open
3. Compressor circuit breaker or fuse(s) is open
4. Broken supply wires or connector is not making contact
5. Compressor power wires not routed through Comfort Alert
6. Compressor contactor has failed open
1. Compressor contactor coil shorted
2. Electrical load too high for PROT circuit (maximum 1 Amp)
3. 24 V AC wired directly to PROT terminal
1. High head pressure
2. Condenser coil poor air circulation (dirty, blocked, damaged)
3. Condenser fan is not running
4. If low pressure switch is open: Refer to Code 3 for troubleshooting
1. If low pressure switch is open:
a. Low refrigerant charge
b. Evaporator blower is not running
c. Evaporator coil is frozen
d. Faulty metering device
e. Condenser coil is dirty
f. Liquid line restriction (filter drier blocked if present)
2. If high pressure switch is open, go to Flash Code 2 information
3. Intermittent thermostat demand signal
4. System or control board defective
1. Low line voltage to compressor
2. Excessive liquid refrigerant in compressor
3. Compressor bearings are seized
1. Condensing unit power disconnect is open
2. Compressor circuit breaker or fuses are open
3. Compressor contactor has failed open
4. High pressure switch is open and requires manual reset
5. Broken supply wires or connector is not making contact
6. Unusually long compressor protector reset time due to extreme
ambient temperature
7. Compressor windings are damaged
1. Compressor fuse is open on one phase
2. Broken wire or connector on one phase
3. Compressor motor winding is damaged
4. Utility supply has dropped one phase
1. Compressor running backward due to supply phase reversal
1. Compressor contactor has failed closed
2. Thermostat demand signal not connected to module
1. Control circuit transformer is overloaded
2. Low line voltage to compressor
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