A/C stopped working at some point today

KremericaJuly 18, 2012

Hey All,

I had problems with my A/C unit on a 1500 sq ft house in Houston Texas last year and ended up having to get a new compressor. It was under warranty so I only paid about $100 bucks for the service guy. He said it was knocked out due to a bunch of rolling black out/brown outs during some thunderstorms last year.

anyways, its been running fine until today. I get home around 6pm and my wife says the house has been hot all day. The thermostat reads 82 when I look at it and its noticeably hot in the house compare to normal. I usually leave the A/C thermostat settings at 75 to 76 all day long.

The thermostat appears to be working, I don't hear the A/C fan blowing air from the air ducts and I don't hear air being sucked into the air return filter area. I can hear a fan spinning at low speed.

I went outside to look at the compressor and one of the lines is frozen with ice built up all over it. I go to the other side of the house and the drain from the A/C unit pan is slightly dripping water out of it, but not gushing or anything out of the ordinary.

I was told that I have a sealed unit last year and I can't inspect the coils without tearing open the A/C & heater box up in the attic and then having it taped or sealed back up, so I can't see if something inside the unit in the attic is frozen as well.

Pictures from outside compressor:

So I took the hose and cleaned out the box around the A/C compressor outside and melted all the ice that I could see off the lines. Turned off the A/C inside the house at the thermostat, just turned the whole unit to "off".

What causes this? I noticed that I haven't changed my filter in 3 months and it looks pretty dirty at the return air filter intake area. I ran to home depot and bought a new filter and installed it.

Can I run the heat to melt all the ice out of the system? I live in Houston and normally it is blistering hot, but this week it has been raining most days so the temperatures have been slightly lower than normal.

what should I do next?

Do you need more information?



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Sorry for the pictures in the post, I should have just posted the links. That's going to be rough on mobile or dial up users (if they exist still)

So I vacuumed the air return and replaced the filter. Left the A/C switch off and the fan "ON" just to let the fan blow air through the fins assuming it was iced up in the attic as well as outside. I went outside at the compressor and hosed off all the ice that I could see and cleaned the unit outside.

I waited until about 11pm when I was ready to go to bed and then turned the unit back on and set it for a few degrees higher than normal. It stayed on all night and appears to be working this morning also.

I guess it was just dirty filter and lack of airflow causing it.

    Bookmark   July 19, 2012 at 9:58AM
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Frozen lines usually mean a low charge. The service tech may have not put in the right amount of refrigerant when the new compressor was installed, or the installation was not done correctly and there is a leak.

You should call back the service tech and have him investigate what is going on. No need to turn on the heat to melt the ice. Turn off the unit. The house is warm enough the melt the ice.

    Bookmark   July 19, 2012 at 10:00AM
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I posted before reading your post. A dirty filter is a possibility. If it happens again with the clean filter, then you know you have another problem.

    Bookmark   July 19, 2012 at 10:04AM
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thanks mike,
I'll post an update when I get home this evening and see what my wife reports. hopefully it was just low air flow that caused it. The filter looked pretty dirty. I used to be consistent with changing the filter every 2 months, but forgot about it this time.

Would hiring a duct cleaning service help with cleaning the coils in the attic system (is that the condenser?) if alot of dirt got by the filter and is making it dirty in the attic? or would an A/C tech have to physically break the system open, take it out of the system, hose it off, and then reconnect, and recharge the system ?

    Bookmark   July 19, 2012 at 12:33PM
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Well it looks like it was just a really dirty filter. I turned the A/C off for like 6 hours straight and let the fan blow after putting a new filter in the house and clearing off all the ice from the lines outside at the compressor.

everything is working fine now.

thanks for the help.

    Bookmark   July 24, 2012 at 6:07PM
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