Ice in central AC system...

[Scooter]

So last night it seemed like my AC wasn't cooling. I could hardly feel any air coming out of the vents. The house was definitely cooler than outside, but something was wrong. So I removed the filter, even though it is only 3 months old.

This morning I discover that there is ice on the copper pipes from the house to the compressor outside. The condensor inside is also cold to the touch and sweating.

I cut off the AC but kept the fan blowing hoping to melt the ice. Wife turned it on about 3 - 4 hours later and said it was blowing cold again.

What causes this?

Low freon?

Could a leak in the duct work in the attic cause the system to work too hard and then freeze up?

What about this relatively cool but extremely humid air?

 

[B]

I think it's typically low freon or dirty filters.

 

[sapo1495]

low freon will cause this, but it may not be that serious. I had a small lead from the schrader (sp?) valve (like a tire valve stem) all it took was a few ounces of freon and I'm fine again. A/C tech have very sensitive freon detectors and can usually find a leak in a few minutes.

 

[Brak]

I had my fan go out 4 weeks ago and got it replaced. Then last week it iced up just like Scooter. I turned off the compressor, ran the fan until the ice melted, replaced the filter (which was a month and a half old, 3-month life), and have not had a problem since.

I'd heard that low freon could cause this problem as well as a dirty filter. Seem's like everything is ok now so I'm gong to blame the filter. I was thinking that the repairman may have done something to get some "repeat" business.

 

[NickDanger]

One of the easiest things to do that most people don't do is rinse the fins. Go outside to your fan and spray inside the unit to rinse off the delicate metal fins surrounding the fan.

 

[Brak]

The fan I'm talking about is the one that blows air around the inside of the house. It is a squirrel cage fan and is inside the house inside the AC unit.

Sounds like you are talking about the outside compressor fan?

 

[Squirrel]

Gonna hafta replace the coil.... enjoy.

 

[Brak]

Update:
My unit froze up again and I defrosted it. This was after replacing the filter so that wasn't the problem. Then it seemed like it wasn't cooling the house very well so I called the AC repair company and the guy came out and said the freon was low. So we're cool now.

 

[Scooter]

AC Update:

Here's what I did:
Rinsed the fins
repaired leaks in the ducts
used my leaf blower to make sure the soffet vents weren't blocked by insulation
replaced the air filter

But the air coming out of the vents was only 64 degrees. And the AC was running all day just to keep the house at 74 degrees.

My unit is a 13-year old York and the only repair guy listed in the phone book under "York" was Air Control Mechanical. Robert, the owner, came out and found a freon leak and added a bunch of freon. $224. He was very nice and seems quite trustworthy.

Now the air blowing out of vents is 52 degrees.

Ahhhhhh!