Window Air Conditioner: Compressor humming but not working
If you turn the air conditioner off and then back on too quickly, the pressure of the refrigerant gas rises too high; as a result, the compressor hums and won't start until the refrigerant pressure equalizes between the evaporator and condenser coils. Once you turn the air conditioner off, leave it off for several minutes before restarting it. Other reasons the compressor is humming but not starting include a dirty or otherwise restricted condenser coil or the short cycling of the compressor.
Replace the window air conditioner compressor
The compressor is a pump that compresses the refrigerant-Freon-that's sealed in the window air conditioner. If the compressor doesn't run when activated, have a refrigerator service technician replace it; by law, an EPA-licensed technician must do this repair because it involves Freon.
These step-by-step repair guides will help you safely fix what’s broken on your window air conditioner.
If your window air conditioner isn’t cooling properly, it might need a new ambient thermistor. You can replace it yourself following these instructions.
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The electronic control board is the brain of your window air conditioner. Here’s how to replace it.