506467-01 Page 15 of 19Issue 1946
LED Status Fault Description Troubleshooting Information
POWER
(Green)
Module has power Supply voltage is present at module terminals
TRIP
(Red)
Thermostat demand signal
Y1 is present, but the
compressor is not running
1. Compressor protector is open
• Check for high head pressure
• Check compressor supply voltage
2. Outdoor unit power disconnect is open
3. Compressor circuit breaker or fuse(s) is open
4. Broken wire or connector is not making contact
5. Low pressure switch open if present in system
6. Compressor contactor has failed open
ALERT
(Yellow)
Flash Code 1
Long Run Time
Compressor is running
extremely long run cycles
--
ALERT
(Yellow)
Flash Code 2
System Pressure Trip
Discharge or suction
pressure out of limits or
compressor overloaded
1. High head pressure
• Check high pressure switch if present in system
• Check if system is overcharged with refrigerant
• Check for non-con
densable in system
2. Condenser coil poor air circulation (dirty, blocked, damaged)
3. Condenser fan is not running
• Check fan capacitor
• Check fan wiring and connectors
• Check fan motor for failure or blockage
4. Return air duct has substantial leakage
5. If low pressure switch present in system, check Flash Code 1 information
ALERT
(Yellow)
Flash Code 3
Short Cycling
Compressor is running only
briey
1. Thermostat demand signal is intermittent
2. Time delay relay or control board defective
3. If high pressure switch present, go to Flash Code 2 information
4. If low pressure switch present, go to Flash Code 1 information
ALERT
(Yellow)
Flash Code 4
Locked Rotor 1. Run capacitor has failed
2. Low line voltage (contact utility if voltage at disconnect is low)
• Check wiring connections
3. Excessive liquid refrigerant in compressor
4. Compressor bearing are seized
5. Measure compressor oil level
ALERT
(Yellow)
Flash Code 5
Open Circuit 1. Outdoor unit power disconnect is open
2. Compressor circuit breaker or fuse(s) is open
3. Compressor contactor has failed open
• Check compressor contactor wiring and connectors
• Check for compressor contactor failure (burned, pitted, or open)
• Check wiring and connectors between supply and compressor
• Check for low pilot voltage at compressor contactor coil
4. High pressure switch is open and requires manual reset
5. Open circuit in compressor supply wiring or connections
6. Unusually long compressor protector reset time due to extreme ambient temperature
7. Compressor windings are damaged
• Check compressor motor winding resistance
ALERT
(Yellow)
Flash Code 6
Open Start Circuit
Current only in run circuit
1. Run capacitor has failed
2. Open circuit in compressor start wiring or connections
• Check wiring and connectors between supply and the compressor S terminal
3. Compressor start winding is damaged
• Check compressor motor winding resistance
Table 5. Diagnostic Module Codes
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