HVACopediaGoodman · Heat pump troubleshooting
Reversing valve not shifting - ComfortNet heat pumps
What is going on
Heat pump stays in one mode, or suction pressure/temperature is abnormally high because the valve is stuck between positions or leaking.
Likely causes
- No 24 V to the solenoid
- Open solenoid coil
- Pilot plunger stuck
- Main slide stuck mid-position or leaking
Check in this order
- In cooling mode check for 24 V at the reversing valve solenoid; if none, trace the control voltage (legacy wiring: thermostat O terminal and wire).
- With voltage present, loosen the coil nut and slide the coil off - you should feel slight magnetic pull and hear the pilot plunger click. No click = stuck pilot.
- Check coil continuity; replace an open coil. Coil OK with 24 V present but valve will not move = replace the valve.
- To try freeing a stuck slide raise head pressure in cooling (block the outdoor fan discharge), then switch between cooling and heating.
- Leak test by temperature the suction line after the valve should match true suction; a difference of about 4 F or more means the valve is leaking internally.
Applies to: ComfortNet ASZC/GSZC/DSZC heat pumps
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Source: Goodman ComfortNet ASXC/GSXC/DSXC, ASZC/GSZC/DSZC, AVPTC/MBVC service manual, Reversing Valve Troubleshooting p.22. Written in our own words; check the manual for your exact model.
For licensed technicians. Gas, electrical and refrigerant work must be done by a qualified, licensed person. Shut off power and gas before servicing, never bypass a safety control, and follow the manufacturer’s manual for the exact model; it and local codes always take priority. HVACopedia is not affiliated with any manufacturer; brand and model names only identify the equipment.