My window air conditioning unit started freeIng up...?

Question

It just started haopening today, you can actually see the frost build up inside, I had to shut it off. Any ideas why its doing this?

Answer 1

If the filter is dirty, or the air is restricted on the indoor coil, it can cause this problem. You may also try a higher fan speed. Low air speed, and low temps can cause frost.

Answer 2

Since it is less likely that it has a refrigerant leak I would look at the filter and if that's not it it could be that the coil itself is dirty enough to cause it to freeze.

Dirt may be between the fins and hard to see.

This usually only happens when filters are left out for some period of time.

Since it cant pick up much heat the temp. of the coil reaches below 32 deg and frost forms and the frost of coarse adds to the problem and becomes a block of ice.

Cleaning is typically done with a cleaner sprayed on to dissolve the dirt and may be washed out if necessary.

Removal of the window unit would be a must to be able to access and clean properly.