A heat pump is an air conditioner that can run in reverse. In Chandler that means it carries the full cooling load from May through October and then heats on winter nights that average 41°F in January. Because it works year-round, it wears faster than a cooling-only AC and has a few failure points an AC does not.
Summer failures
In cooling mode a heat pump fails like an air conditioner: weak capacitors, burned contactors, overheating fan motors, low refrigerant and clogged condensate drains. Chandler’s 106°F average July high is hard on all of them.
Winter failures
- Reversing valve stuck. The system blows cool air when set to heat. Sometimes the valve’s solenoid coil has failed (repairable); sometimes the valve itself is stuck (a bigger repair).
- Defrost problems. On cold, damp nights the outdoor coil can ice. A failed defrost board or sensor lets the ice build until airflow stops.
- Backup heat not working. Electric heat strips in the air handler cover the coldest nights. Chandler’s record low is 15°F. Burned elements or failed sequencers leave you with lukewarm air when you need it most.
- Thermostat set-up. A thermostat configured for a gas furnace will not control a heat pump correctly. We see this after DIY thermostat swaps.
Quick checks
- Confirm the thermostat is set to Heat, not Auto or Emergency Heat.
- Look at the outdoor unit: light frost that clears periodically is normal; a solid block of ice is not.
- Replace the filter.
- Check the air handler breaker for the heat strips.
Repair or replace?
Most heat pump repairs are electrical parts and are worth doing. A failed compressor or reversing valve on a system older than about 12 years often points toward replacement. See heat pump replacement in Chandler.
Heat pump not heating or cooling? Call 480-719-8109 — a real person in the East Valley answers.