I first noticed last week when we had the thermostat set at 79, and the temp inside was 81. And the unit just seemed to run all the time, but it was not very efficient. I suggested to my husband, we needed to change the filter. But it didn't happen. When we finally did change the filter, it wasn't really that dirty so I knew it was a bigger problem than a dirty filter. So, with the filter removed it was possible to peek into the unit and see the real problem - a layer of iced up frozen dust and grime.
If you have this problem, you can simply clean the evaporator coils yourself and save yourself a couple hundred dollars on an AC service call. If you clean your coils and still have a problem reaching temp, then it is possible you have depleted some freon (if icing coils reappear), and you'll need to call a service guy.
Anyway, it's not hard to clean the coils, we just looked up a couple youtube videos on how to clean AC coils. You probably will only need to clean the underside of the A frame coils where the air is pulled through. The top side of ours was clean. We ran to the home improvement store and purchased a water based cleaning spray that was a foaming cleanser, it stated self rinsing so no water flush would be necessary. It cost $5.48. We also purchased a roll of metal tape to seal up the AC cabinet seams for $7.48.
- Turn off AC at thermostat. Gather your safety gear - eye protection, face mask and something to cover your hair from debris (a hat or hanky). You will also need a flashlight, stiff brush, cleansing spray, plastic sheeting and pans to collect debris, metal tape, and a household fan.
- Line the area under your A frame unit with plastic, then place pans or wash tubs under to collect the melting ice, water and grime.
- If iced up, melt ice using a hair dryer. Do not damage the evaporator fins by chipping away ice, just be patient and melt it.
- Using a stiff plastic brush (I used an plastic old dish washing brush with a long handle), dip it in water and brush down the big grime and dust layer toward the drip tray.
- When you can see the coils and they are kind of clear of debris, don your safety gear and spray the foaming cleanser all over the coils.on the underside of the A frame. Let it sit for five or more minutes until the foam has mostly dissipated. Then take your stiff brush and clean the remaining dirt from the coils. I also had to use a 2 ft long shish kabob poker to dislodge dirt from the top apex of the inside of the unit.
- If you have an air compressor, it will make cleaning and drying the unit easy. We used compressed air to blow out all remaining dirt and used it to help dry the evaporator fins. You must dry your unit completely before starting up again, or you risk icing up.
- Dry your AC evaporator coils with a household fan pointed in there to remove all moisture. We have a large window fan we pointed up there for an hour before we started up the unit.
- Replace your cabinet panels and tape seams shut with metal AC tape. Replace the air filter.
- Turn on your thermostat. Wait several hours for it to reach temp. Ours lowered the temp 1 degree in 30 minutes, but then next degree took an hour.
- After a couple hours of your AC unit running, check the coils by removing your air filter and peek up into the unit to make sure the coils are not iced up. If not, just be patient - its working.
