HVACopediaCarrier · Heat pump troubleshooting
Delay before the compressor restarts
What is going on
The outdoor unit waits before starting again - usually normal.
Likely causes
- Pressure equalizer valve cycle after every compressor stop
- 10-minute warm-up after high voltage power-up
- Protection delays from fault codes
Check in this order
- After every compressor stop the pressure equalizer valve opens for 150 s, then 15 s off before the next start - this cannot be bypassed.
- After power-up the compressor sump warms for 10 minutes (code 68).
- Brown-out recovery delay can be skipped by briefly shorting the Forced Defrost pins.
- Check the STATUS light for any other fault delay.
Applies to: Carrier Infinity 18VS variable speed heat pump 25VNA8
More heat pump guides
- Amber STATUS or green COMM light not on
- Heat pump will not defrost - HK32EA defrost board
- Noisy compressor or loud defrost shift - Carrier split systems
- Outdoor ECM fan not running - Carrier 25HNB9/24ANB1
- Outdoor unit unresponsive after several faults
- Outdoor unit will not run - HK32EA defrost board heat pumps
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Source: Carrier 25VNA8 / 24VNA9 Service Manual, Timing / delays p.8. 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.