Troubleshooting guide
Heat pump blowing warm air in cooling mode? Here is what is happening and what to do.
A heat pump blowing warm air in cooling mode is almost always a refrigerant problem or a stuck reversing valve. Less commonly, the system is set to 'fan only' or the outdoor unit isn't running. If the outdoor unit isn't spinning, check power. Otherwise this needs a tech.
Likely causes, ranked by probability
- 1
Stuck reversing valve
Valve stuck in heat mode position.
Likelihood 35%
- 2
Low or no refrigerant
System can't move heat without refrigerant.
Likelihood 30%
- 3
Mode set incorrectly
Set to fan or heat instead of cool.
Likelihood 20%
- 4
Outdoor unit not running
Power or component failure at outdoor unit.
Likelihood 15%
What you can try first
- · Confirm mode is set to cool, not fan or heat
- · Verify outdoor unit is running
When to call us: Mode is correct, outdoor unit runs, and the air is still warm.
When a cleaning helps, and when to call a repair pro
A good portion of “something is off” symptoms (musty smell, weak airflow, water dripping from the indoor unit, surface mold) trace back to a dirty blower wheel, clogged drain, or biofilm on the coil. A full disassembly cleaning solves those. If we get on site and find an electrical or mechanical fault (a failing capacitor, a stuck reversing valve, refrigerant issues), we will tell you and recommend a heat pump repair contractor. We do not do repairs ourselves.
Frequently asked questions
Is heat pump blowing warm air in cooling mode dangerous?
Most causes of "heat pump blowing warm air in cooling mode" are not immediately dangerous, but ignoring them can damage the system over time. Mode is correct, outdoor unit runs, and the air is still warm.
Can a cleaning fix this?
Sometimes. Biofilm, dirty coils, and clogged drain lines often resolve after a deep clean. Mechanical or electrical issues need a heat pump repair contractor instead.
Do you do repairs?
No. We focus on cleaning and twice-yearly maintenance. If your system needs a part replaced or an electrical fix, we will tell you what we see and recommend a repair contractor.
Try a cleaning first.
If the symptom traces back to a dirty unit, we can fix it. If it does not, we will tell you and point you to a repair pro.