HVACopediaCarrier · Heat pump · Heating
Non-communicating heat pump: heating cycle (HK32EA001/007 and 003/008)
What happens, in order
- Thermostat makes R-Y and R-G on a call for heat (no R-O, so the reversing valve stays in heating position)
- R-Y feeds the safeties and energizes the contactor and terminal T1; T1 powers the defrost logic and defrost cannot work without it
- On 003/008 boards if compressor was off 5 min, OF2/T2 energize and outdoor fan and compressor start
- On 001/007 boards the contactor and fan start straight away; there is no compressor delay on these boards
- Thermostat satisfied R-Y drops and compressor and fan stop; 003/008 boards restart the 5-minute timer
Timings and thresholds
| Item | Value |
|---|---|
| Compressor time delay | 5 min (003/008 only) |
Applies to: Carrier / Bryant / Payne split heat pumps with HK32EA defrost control boards (Performance Series and Comfort Series)
Models
More Carrier heat pump sequences
- Single-stage communicating heat pump: time delays and operating functions · Startup
- Variable-speed unit: power-up and compressor time delays · Startup
- Non-communicating heat pump: cooling with 5-minute compressor delay (HK32EA003/008) · Cooling
- Non-communicating heat pump: time/temperature defrost and Quiet Shift · Defrost
- Single-stage communicating heat pump: demand defrost, Auto interval and Quiet Shift-2 · Defrost
- Variable-speed heat pump: demand defrost with Auto interval · Defrost
- Single-stage communicating heat pump: pressure switch protection and lockout · Other
- Variable-speed unit: high pressure switch protection and lockout · Other
Related
Take it to the job
Sequences of operation, error codes and tips work offline in the HVACopedia app.
Source: Carrier-Bryant residential A/C + HP Application Guideline and Service Manual (R-410A, 24-25), System Function and Sequence of Operation, Defrost Control. 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.