Heat pump not heating or cooling
Most Naples homes cool and heat with a heat pump. When it won't switch modes, runs on backup heat or stops cooling, the cause is usually in a handful of parts.
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A heat pump uses a reversing valve to move heat out of the house in summer and into it in winter, with electric heat strips as backup. Problems tend to show up on the first cool mornings of the year, or when the system switches between modes.
What you might notice
- Blows cool air in heat mode
- Auxiliary or emergency heat runs much of the time
- Outdoor unit ices over and doesn't clear
- Heats but won't cool, or cools but won't heat
- Loud noise when switching modes
Common causes
Reversing valve or solenoid
Stuck valves keep the system in one mode.
Thermostat configuration
A thermostat set up for a conventional AC won't control a heat pump correctly.
Defrost problems
Failed sensors or boards stop the outdoor coil from defrosting.
Refrigerant leaks
Low charge reduces both heating and cooling.
Heat strip problems
Failed elements or sequencers affect backup heat.
Safe checks you can make first
- Confirm the thermostat is set to Heat or Cool as intended
- Check that it's configured for a heat pump (in its settings or app)
- Replace a dirty filter
- Check breakers for both the outdoor unit and air handler heat strips
How a Uniform technician diagnoses it
We test operation in both modes, check reversing valve and defrost controls, verify thermostat configuration, measure heat strip current and examine the refrigerant circuit. If a repair or replacement decision is needed, you get options in writing.
Repair options
| Option | When it fits |
|---|---|
| Thermostat correction | Configuration is wrong. |
| Valve, sensor or board repair | A control component has failed. |
| Leak repair | Refrigerant is low and repairable. |
| Replacement | Major failure on an older system. See heat pump service. |
You get a written estimate after diagnosis and before any work starts. See what changes a quote in our Naples AC repair cost guide.
Why homeowners choose Uniform
The technician who comes to your home has passed a guaranteed background check and works for a licensed, insured air conditioning contractor. Florida license number posted at launch. Verify any Florida A/C contractor at DBPR.
Request a call back
Tell us what's happening and we'll call you to schedule. Every visit starts with diagnosis and a written estimate.
Other AC problems: ac not cooling, ac won't turn on, ac leaking water, frozen ac coil, weak airflow, ac runs constantly, thermostat problems, ac noise or smell, high ac electric bill.
Frequently asked questions
Is it normal for my heat pump to blow cool air in heat mode?
Heat pump air feels warm but not hot, often in the 90s °F. Air that feels cool in heat mode is a problem.
What does emergency heat mean?
It runs only the backup heat strips, bypassing the heat pump. Use it only when the heat pump has failed.
How do I know if I have a heat pump?
Check the outdoor unit label, or look for Aux or Em Heat on your thermostat.
Need an HVAC tech you can trust in your home?
Call now. We'll ask a few questions, give you an honest arrival window and send a background-checked, licensed technician in uniform.
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