HVACopediaKeepRite · Heat pump · Cooling
Heat pump with 5-minute compressor delay: cooling and heating start
What happens, in order
- On power-up (24 V between R and C) a 5-minute timer starts and the compressor will not run until it ends
- Cooling call thermostat makes R-O, R-Y and R-G; R-O shifts the reversing valve to cooling
- R-Y feeds the safeties and energizes T1 on the board; if the compressor has been off 5 minutes, relay OF2 and T2 energize to close the contactor and start the outdoor fan and compressor
- Heating call R-Y and R-G only; T1 energizes the defrost logic and the same 5 minute check applies before fan and compressor start
- Satisfied R-Y drops, compressor and fan stop, and the 5 minute timer starts again; after a power interruption another cycle still waits 5 minutes
- With ICP thermostats the reversing valve stays in cooling position until the thermostat goes to heat or off
Timings and thresholds
| Item | Value |
|---|---|
| Compressor time delay | 5 min |
Applies to: KeepRite / ICP / Tempstar / Heil Performance Series split heat pumps (defrost control Fast #1174185)
Models
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Source: KeepRite/ICP/Tempstar/Heil R-410A and R-22 split A/C and HP service manual 421 08 5400 04, 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.