Window Air Conditioner: Water not draining

If your window air conditioner has a drain hole in the back--not all do--and it's not draining water, clear the drain hole and then clean the base of the unit to get rid of dirt that could enter the drain.

Leveling the air conditioner with a slightly backward tilt may also be necessary when you see your window air conditioner not draining water. The slightly backward tilt helps drain water flow to the back of the cabinet tray and down through the drain hole.

If you have a drain hose connected to the drain tray, check the drain hose for a clog when you see the window air conditioner not draining water.

window air conditioner

These repairs may help solve your window air conditioner problem

Clear a window air conditioner clogged condensate drain

Clear a window air conditioner clogged condensate drain

Many (but not all) window air conditioners have a drain hole in the back to let condensate water drain outdoors. If the drain hole is clogged, clean the base of unit and clear the clog in the drain hole.

Level the window air conditioner

Level the window air conditioner

The back of the air conditioner should be slightly lower than the front so condensate water drains outdoor. If water drains into the room, reinstall the air conditioner so it tips backwards slightly.

Symptoms for window air conditioners

Choose a symptom to see related window air conditioner repairs.

Main causes: turning the air conditioner off and the back on too quickly, dirty or restricted condenser coil, compressor failure
Main causes: dirty air filter, air conditioner is too small for the room, temperature set too cold, control failure
Main causes: bad compressor, lack of refrigerant, bad compressor start relay, electronic control board failure
Main causes: clogged condensate drain, air conditioner not leveled properly, leaky window air seals
Main causes: lack of electrical power, bad electronic control board, wiring failure, bad temperature sensor
Main causes: clogged drain hole, air conditioner not leveled properly

Repair guides for window air conditioners

These step-by-step repair guides will help you safely fix what’s broken on your window air conditioner.

How to replace a window air conditioner ambient thermistor

If your window air conditioner isn’t cooling properly, it might need a new ambient thermistor. You can replace it yourself following these instructions.

Repair difficulty
Time required
 45 minutes or less
How to replace a window air conditioner condenser fan

If the condenser fan blade is broken or the condenser fan motor won’t run, you can replace the broken parts yourself by following these instructions.

Repair difficulty
Time required
 90 minutes or less
How to replace a window air conditioner electronic control board

The electronic control board is the brain of your window air conditioner. Here’s how to replace it.

Repair difficulty
Time required
 45 minutes or less

Articles and videos common to all room air conditioners

Use the advice and tips in these articles and videos to get the most out of your window air conditioner.

September 26, 2019

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