Help the girl who knows jack about air conditioning...

A little background:

Last fall, I called the guy to come out and check/clean out my home heating system before I started using it for the winter.

Crack in the heat exchanger.

So I ended up having to buy a new heater (!@#$%&*!). I got several estimates and wound up going with the cheapest guy (precisely because he was the cheapest guy–by about $700!).

The heater gave love and warmth all winter, and I have no complaints about that.

Yesterday morning, however, I turned on the A/C for the first time, because the weather man predicted a day close to 90 degrees, and my dogs are cooped up at home all day (on this particular day, my pseudo-kid was sacked out on the couch, too).

I left it on overnight last night, because I was still feeling kind of warm when I went to bed. Then this morning, as I was yawning, stretching, and greeting the morning out in the back yard with the dogs, I happened to look over at my A/C unit.

It was as silent as a dead lamb.

Funny, I thought. I could have sworn the air was blasting when I walked out here…

I ducked my head back into the house and, indeed, air was coming out of the vents…

Only it was being supplied by my new HEATING unit in the basement. Wasn’t HOT air… but it was coming from the heating unit (which was just humming along). And yes, I did check to make sure that the thermostat was set on “Cool” (but if it hadn’t been, the dogs and the kid would surely have baked yesterday).

Here’s the Dumb Girlie question…

Should I be concerned? :confused:

Does this mean I can detach my outside A/C (which worked like a charm as of last summer) and sell it at a garage sale?


Central air conditioning has two parts (I’m oversimplifying greatly, but whachagonnado): a compressor unit (the outside part with the big fan you see) and a blower unit, which is probably what you are taking for the furnace, since it is probably attached thereto.

Your blower blows air. It doesn’t care if it’s warm or cool. This is the part you control with the switch on your thermostat labeled “FAN.” ON will cause the blower to run all the time, AUTO will cause the blower to run only when the compressor runs.

The compressor is controlled by the switch on your thermostat labeled “HEAT-OFF-COOL.” When you set this to COOL, the thermostat will trigger the compressor to run when it is needed to cool the air down.

Hope this helps.

Yes, it does help. Unfortunately, it sounds like my compressor unit is shot…

At any rate, thanks!!!

I wouldn’t jump to conclusions yet. The guy that hooked up your new furnace could have caused a freon (or R134a I think) leak. The outside compressor has a pressure sensor that will turn off the compressor if the pressure of the coolant is too high or too low. This is to avoid ruining the compressor (an expensive fix). Or a wire could have come loose somewhere. Get someone to check it out. Fiddle with the switch, maybe it’s a bit corroded.

Also, are you sure you don’t have your fan set to run all the time? I know some thermostats allow that. Maybe you bumped it when you turned on your AC?

I’m sure. I checked carefully when I turned the thing on yesterday morning, and double-checked the settings THIS morning, when I discovered that my compressor was not running.

It did occur to me that maybe the installer of the heating unit had accidentally screwed up some connection.

At any rate, I didn’t have the time or the know-how to check things out before work this morning, so I figured I’d see if I could learn something before I leave work today, and check things out tonight. In the meantime, I’ve still got everything on and running, in hopes of keeping the dogs from suffocating.

My house is pretty well-shaded and has awnings, so it should stay pretty cool, even if all they’re getting is, essentially, a fan.

Thanks, Dilbert!