Goodman Heat Pump: CPLJ
Re: Won't Defrost
The Goodman CPLJ Heat Pump uses a Time & Temperature Defrost Board.
- A defrost thermostat mounted to the outdoor coil closes at approximately 30 deg. and opens at approximately 60 deg.
- An adjustable setting on the board allows adjustment of the time between defrost cycles to either 30, 60 or 90 minutes.
- When the board receives 24VAC on the "Y" terminal the timer starts. When the compressor runtime exceeds the set defrost time, and the defrost thermostat is closed, a defrost cycle will be initiated.
||Bad or Disconnected Defrost Stat
||Bad Defrost Board
||Low Refrigerant Charge
||Bad Cond Fan Motor / Capacitor
||Mis-Located Defrost Stat
||Stuck Reversing Valve
||Defrost Timer Set Too Long
1. Check Operating Status
- Set the thermostat to call for heat.
- Ensure that the compressor and outdoor fan start and run properly.
2. Check Fan Motor
- With the compressor operating, use a multi-meter to check for 230VAC power between the motor's Black and Red wires.
- No Power = Bad Defrost Board or In Defrost Mode
- Power but No Operation = Bad Fan Motor or Capacitor
3. Check Refrigerant Charge
Hook-up refrigerant gauges to the pressure ports on the unit.
- Blue ⇔ "True Suction" Low Pressure
- Red ⇔ High Pressure (either refrigerant line)
- Monitor pressures as the system operates.
- DO NOT ATTEMPT TO ADJUST REFRIGERANT CHARGE IF THE OUTDOOR COIL IS STILL FROZEN!
|Normal Pressure Range
||0-30 Deg O/D
||30-50 Deg O/D
- 20-40 Suction
- 150-225 Discharge
- 40-75 Suction
- 170-260 Discharge
- Low Pressure Issues
- Low Suction + Low Discharge + Metering Device Frosting = Low Refrigerant Charge
- Try adding refrigerant through the Low Pressure gauge.
- Suction and Discharge Pressures should gradually increase as refrigerant is added.
4. Check Defrost Board
- Check for 24VAC between "C" and "R" on the defrost board.
- No Power = Mis-wired Low Voltage
- Check for 24VAC between "C" and "Y" on the defrost board.
- No Power on "Y" + Unit Operating = Stuck Contactor
- Check for 24VAC between "C" and "DFT" on the defrost board.
- No Power = Defrost Stat Open (Not ready for defrost)
- Cold Coil + Open Defrost Stat = Bad or Disconnected Defrost Stat
- Warm Coil + Open Defrost Stat = Normal
- It may be necessary to temporarily bypass the stat by placing a jumper across "R" and "DFT".
- Speed-up the timer by jumping the Test pins on the defrost board.
- A defrost cycle should initiate within 5 seconds (Outdoor Fan Stops, Reversing Valve Switches to Cool Mode, and Energizes Aux Heaters).
- Power on "R" and "Y" + DFT Circuit Closed + No Defrost Cycle = Bad Defrost Board
- Outdoor Fan Stops + Reversing Valve Doesn't Switch = Stuck Reversing Valve, Bad Reversing Valve Coil or Loose Wiring