HVACopediaGoodman-Amana-Daikin · Heat pump · Defrost
Timed defrost with sensor and override
What happens, in order
- Heat pump runs in heating with the reversing valve de-energized
- Defrost board checks the outdoor coil sensor at the chosen interval of heat pump run time (30, 60 or 90 min)
- Timing starts when the sensor closes (about 31 F) and the thermostat calls for heat
- If the sensor is still closed at the end of the interval, defrost starts
- Outdoor fan relay opens (outdoor fan off)
- Reversing valve and electric heat are energized (24 V sent to O and W2)
- Defrost ends when the sensor opens (about 75 F)
- If the sensor never opens, the board ends defrost on a 10 minute override (12 minutes on the upgraded board)
- At the end the outdoor fan restarts and the reversing valve and electric heat de-energize; normal heating resumes
- Boards PCBDM133 / PCBDM160 factory DLY setting stops the compressor for 30 s while the valve shifts at the start and end of defrost; move the jumper to NORM to skip the delay
Timings and thresholds
| Item | Value |
|---|---|
| Defrost check interval | 30, 60 or 90 min |
| Sensor closes | about 31 F |
| Sensor opens / defrost ends | about 75 F |
| Override | 10 min (12 min upgraded control) |
| Compressor delay on shift (DLY) | 30 s |
Applies to: Goodman ASZ/GSZ/DSZ R-410A heat pumps (incl. GSZH5); Goodman R-32 GLZS / ALZS heat pumps
Models
More Goodman-Amana-Daikin heat pump sequences
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Source: Goodman R-410A ASX/GSX/DSX A-C and ASZ/GSZ/DSZ HP service RS6200006, Defrost Operation; Goodman R-32 service RS6200301, Defrost Cycle. Written in our own words; timings can differ by model and software version, so check the manual for your exact unit.
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.