Air conditioning repair and diagnosis
Cooling failures, airflow issues, and refrigerant questions.
- Not cooling
- Frozen coil
- Refrigerant
- Condenser faults
Troubleshooting
5 articlesSymptom first, cause second. Start here when something has stopped working.
-
AC Unit Frozen? Thaw It Safely, Then Find Out Why (2026) Ice on your AC coil or copper line? Shut the cooling off first, thaw it with the fan, then check airflow before refrigerant. What each cause costs to fix. Updated -
AC Not Cooling? 7 Causes and How to Fix Each (2026) AC running but not cooling? Work the 7 real causes in order of likelihood: airflow, thermostat, frozen coil, power, capacitor, condenser, refrigerant. Updated -
Heat Pump Freezing Up? What Is Normal and How to Fix It (2026) Frost on a heat pump in winter is normal; a block of ice is not. How to tell them apart, what to do right away, and the causes behind each kind of freeze-up. Updated -
AC Not Turning On? 8 Checks Before You Call (2026) AC not turning on at all? Find which half is dead, then check the thermostat, the 3-amp fuse, the drain safety switch, breakers, disconnect and contactor. Updated -
Heat Pump Not Heating? 8 Causes, Checked in Order (2026) Heat pump not heating? Check the thermostat mode and setup, the filter, the outdoor unit and the breakers first, then the heat strips and the compressor. Updated
Not sure which guide fits?
Start by naming what the system is doing, because each symptom has its own short list. Air moving but not cold sends you to the outdoor unit: is the fan on top spinning, and is the copper line near the house cold? Weak or no air sends you inside, to the filter, the blower, or an indoor coil that has iced over. AC not cooling walks both branches in order.
A heat pump adds two winter questions. Frost that clears on its own is the defrost cycle working; a coil sealed in ice for hours is a fault, covered in heat pump freezing up. A unit that runs without warming the house is most often a thermostat set up for the wrong equipment, the first cause in heat pump not heating.
Two faults are not worth waiting on: a breaker that trips again right after you reset it, and an outdoor unit that hums without starting. Both point to electrical parts, and running the system that way can take the compressor with it.