Carrier 38AU - Manual (Page 29)

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Table 13 — LED Status Codes
Status LED Status LED Description Status LED Troubleshooting Information
Green “POWER” Module has power Supply voltage is present at module terminals
Red “TRIP”
LED On Solid
Thermostat demand signal Y
is present, but the
compressor is not running.
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
Red “TRIP” LED
Flashing
The anti-short cycle timer (3 minutes), in module is preventing compressor
restart.
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”
LED On Solid
A short circuit or over current
condition exists on PROT
terminal.
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
Yellow “ALERT”
Flash Code 2
System Pressure Trip
Discharge pressure out of
limits or compressor
overload (if no high pressure
switch in system)
LOCKOUT
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
Yellow “ALERT”
Flash Code 3
Short Cycling
Compressor is running only
briefly LOCKOUT
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
Yellow “ALERT”
Flash Code 4
Locked Rotor
LOCKOUT
1. Low line voltage to compressor
2. Excessive liquid refrigerant in compressor
3. Compressor bearings are seized
Yellow “ALERT”
Flash Code 5
Open Circuit 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
Yellow “ALERT”
Flash Code 6
Missing Phase
LOCKOUT
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
Yellow “ALERT”
Flash Code 7
Reverse Phase
LOCKOUT
1. Compressor running backward due to supply
phase reversal
Yellow “ALERT”
Flash Code 8
Welded Contactor
Compressor always runs
1. Compressor contactor has failed closed
2. Thermostat demand signal not connected to
module
Yellow “ALERT”
Flash Code 9
Low Voltage
Control circuit < 18VAC
1. Control circuit transformer is overloaded
2. Low line voltage to compressor