Why is my AC running but not cooling?

Common causes include a dirty air filter, low refrigerant, frozen evaporator coil, faulty capacitor, or a dirty condenser. Try replacing the filter and checking the thermostat first. If the problem persists, call LegendAir at (215) 317-6099 for current appointment availability.

How do I reset my AC unit?

Turn off the thermostat, switch the AC breaker off, wait 5 minutes, turn the breaker back on, then turn on the thermostat. If the AC still won't cool, the issue is likely a failed component requiring professional repair. Call (215) 317-6099.

AC Not Cooling? 10 Troubleshooting Steps Before Calling for Repair

Summary: AC not cooling your Warminster home? Follow these 10 step-by-step troubleshooting steps before calling for repair. Learn when to DIY and when you need a professional HVAC technician.

Published 2026-01-20. Updated 2026-02-06.

Safe checks before calling

Confirm cooling mode and set point, inspect the filter, verify registers are open, and check the labeled breakers once. Note whether the indoor blower and outdoor unit operate. Do not remove panels or touch capacitors, contactors, or refrigerant lines.

Shut the AC down for these signs

Stop operation for smoke, sparking, a burning odor, repeated breaker trips, severe noise, active water near electrical components, or visible ice. Ice can result from airflow or refrigeration faults and should not be chipped away.

What diagnosis should establish

The technician should identify the failed condition and supporting measurements, explain whether another fault contributed, and provide written repair options. Ask how operation will be verified after approved work.

Authoritative Sources

Need diagnosis? Call (215) 317-6099 or book service. Planning an installation or replacement? Request a free project estimate.

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Frequently Asked Questions

Why is my AC running but not cooling?: Common causes include a dirty air filter, low refrigerant, frozen evaporator coil, faulty capacitor, or a dirty condenser. Try replacing the filter and checking the thermostat first. If the problem persists, call LegendAir at (215) 317-6099 for current appointment availability.
How do I reset my AC unit?: Turn off the thermostat, switch the AC breaker off, wait 5 minutes, turn the breaker back on, then turn on the thermostat. If the AC still won't cool, the issue is likely a failed component requiring professional repair. Call (215) 317-6099.