A/C weirdness

[Jud McCranie]

I'm having a weird problem with our air conditioner. It is actually a heat pump. About 8-10 days ago it was running but not cold air. I cut it off for a few minutes and then it started working again. Then last Wednesday it quit working and even seemed to be blowing heated air! I'm fairly sure that it was heated air rather than recirculated air. I tried cutting it off for a while, but when I cut it back on the compressor wouldn't start. I tried this a couple of times.

Thursday I got the A/C repairmen out. They said it was a burnt out capacitor. They also topped off the coolant, which was a little low. They also cleaned out the drain, which was not working. It worked normally for three days, then today it did basically the same thing - blowing heated air. I cut it off for a few minutes and tried it again. This time the compressor wouldn't come on and it was blowing around room temperature air. I left it off for an hour or two and turned it back on and now it is working again.

So right now it is working, but what is causing the problem? Has the thermostat gone haywire? The night we first had the problem there was strong lightning in the area, but no strikes were especially close.

[Nate Certified Heating and Coo]

Sounds like the reversing valve is getting stuck/not switcing. It could be the thermostat causing it or it could be the valve itself. Bottom line, if it's blowing hot air when you call for cooling then the reversing valve is not doing what it should. You need to have someone that knows what they are doing look at it as the last one did not. You should choose a company that has Nate certified techs. See this link:

[Jud McCranie]

Only one certified in my area and they aren't the one.

I told them that I thought it was actually blowing heated air at one time, but they thought it was just un-cooled air recirculated. I've felt the output of air conditioners enough that I can tell if the compressor is running or not, and there is no doubt in my mind that this was actually putting out heated air.

[Don Young]

Don't forget that the heat pump could be in the cooling mode but the auxillary heat strips are coming on. If the unit is in cooling mode the air from the outside unit should be warm. If it is colder than ambient, it is in the heating mode.

Don Young

[Moe Jones]

You might have a compressor running on its last leg. How old is the compressor? The compressor may be having a hard time in starting and when that happens it might have kicked out on internal overload and after sometime it has reset and will work. Maybe a hard start kit needed?

[Jud McCranie]

I'm not sure. We bought the house 6 years ago and it is 11 years old. It was in 6 years ago, but they added it when they enclosed the upstairs. I think it is 7-8 years old.

[Jud McCranie]

It turns out that was it! It quit working again last night (actually putting out heated air), so I had them here again today. I told them that 3 times now I was sure that the heater was on. At first he turned it on and it was working OK. But within a few minutes, hot air started coming out, and he saw it. He said that I wasn't crazy, I was right. He tracked it down to the thermostat telling the strips to come on when they weren't supposed to. Bought a new thermostat tonight, not installed yet. The night of the first problem there had been a lot of lightning in the area, but no power failures. Perhaps there was enough of a surge to mess it up (stat is only 4 years old).

[Don Young]

Glad you found the problem.

Don Young

[Stormin Mormon]

Can't decide if it's an AC or a heat pump. Identity crisis!

[Jud McCranie]

Yes, but I had to replace the thermostat, and they don't make them like they used to.

My old one (and the one on the other unit in the house) is/was so easy. A switch for Cool/Off/Heat/Em Heat. A switch for the fan On/Auto. A button to Hold the temp. A button to return to the program. Etc. Several buttons to directly program the thing. The new one (both by Honeywell) has no switches and only three buttons (other than up and down) and an extremely long and complex "menu" to try to go through to program it, as opposed to a logical way of doing it.