Status LED
Status LED Description
Green "POWER"
Red "TRIP"
signal Y is present, but the
compressor is not running
Yellow "ALERT"
Low Refrigerant Charge
Flash Code 1
extremely long run cycles
High Refrigerant Charge
Yellow "ALERT"
Flash Code 2
Flash Code number corresponds to a number of LED flashes, followed by a pause and then repeated. TRIP
and ALERT LEDs flashing at same time means control circuit voltage is too low for operation.
LED Troubleshooting Information
Module has power
Thermostat demand
Long Run Time
Compressor is running
System Pressure Trip
Discharge pressure
out of limits or
compressor overloaded
Status LED Troubleshooting Information
Supply voltage is present at module terminals
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.High pressure switch open if present in system
6.Compressor contactor has failed open
1.Low refrigerant charge
2.Evaporator blower is not running
• Check blower relay coil and contacts
• Check blower motor capacitor
• Check blower motor for failure or blockage
• Check evaporator blower wiring and connectors
• Check indoor blower control board
• Check thermostat wiring for open circuit
3.Evaporator coil is frozen
• Check for low suction pressure
• Check for excessively low thermostat setting
• Check evaporator airflow (coil blockages or return air filter)
• Check ductwork or registers for blockage
4.Faulty metering device
• Check TXV bulb installation (size, location and contact)
• Check if TXV/fixed orifice is stuck closed or defective
5. Condenser coil is dirty
6. Liquid line restriction (filter drier blocked if present in
system)
7. Thermostat is malfunctioning
• Check thermostat sub-base or wiring for short circuit
• Check thermostat installation (location, level)
8. Compressor Second Stage Cooling Wiring (Except Part
# 543-0012-00)
• Solenoid plug not connected
• Y2 not wired
1. High head pressure
• Check high pressure switch if present in system
• Check if system is overcharged with
refrigerant
• Check for non-condensable 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
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