Nest
Fan Only Operation / Compressor Not Running
Nest thermostat shows cooling, but only the fan runs and no cold air comes out
Advertisements
Safety Warning
This repair may involve working with high voltage components or water connections. Always unplug the appliance before removing any panels.
If you are not confident in your ability to perform this repair safely, we strongly recommend contacting a professional technician.
Advertisements
Possible Causes
Incorrect wiring of G and Y1 at Nest base, Tripped breaker to outdoor condenser, Failed condenser contactor or capacitor, Low‑pressure or high‑pressure safety switch open
How to Fix / Troubleshooting
Safety: Turn off power to indoor and outdoor units before opening panels.
- Check wiring: Confirm G and Y1 wires are correctly connected at the Nest base and furnace control board.
- Breaker check: Ensure the outdoor condenser breaker is on and any external disconnect is engaged.
- Outdoor unit inspection: Listen for the condenser fan and compressor. If silent, the contactor or capacitor may be faulty.
- Professional diagnosis: Capacitors and high‑voltage components in the condenser can retain charge and are hazardous. Have an HVAC technician test and replace the contactor, capacitor, or diagnose refrigerant/safety switch issues.
Advertisements
Repair Difficulty
Professional Required
5/5
Required Part
Outdoor Condenser Contactor / Capacitor (not Nest)
Check Price on Amazon
We may earn a commission from links on this page.
Advertisements