HVACopediaKeepRite · Heat pump · Heating
Heat pump: heating cycle with supplemental heat
What happens, in order
- Thermostat makes R-Y and R-G on a call for heat
- R-Y energizes the contactor, starting outdoor fan and compressor; R-G starts the indoor blower on high speed
- If the room keeps falling, the second-stage thermostat makes R-W2, which energizes a relay for the first bank of supplemental electric heat and sends power on to the second heater relay if fitted
- If outdoor temperature falls below the field-installed outdoor thermostat setting, the second bank of supplemental heat comes on
- Thermostat satisfied contactor and relays drop out and heaters and motors stop
Applies to: KeepRite / ICP N4H4, R4H4, WCH4, NXH5 heat pumps
Models
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Source: KeepRite/ICP N4H4-R4H4-WCH4-NXH5 heat pump installation instructions 428 01 5107 10, Defrost and Sequence of Operation. 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.