My central air was cooling just fine all day. Around 5pm tonight the air coming out of the ducts wasn't cold any longer. I have a computer monitor the temps in the different rooms of the house and I noticed that all the rooms were cool (77-78) until around 5pm when the temps started climbing to 83 or so.

I checked the AC various times and the outside fan is spinning just fine. The air coming through the outside unit is cool instead of hot. The air coming out of the ducts is not cold at all. What would cause this to all of a sudden stop cooling. I can't imagine it would be a freon leak since that should take time. Any clues or suggestions? Could it be some drainiage pipe is clogged?

Filter plugged

filter plugged
Do you main the air filter? Or is there another filter. The air filter is one of those electrostatic filters set up on the return grill. The air seems to be coming out at the same force as before. If there is another filter where would it be?

Your fan outside is running but the compressor is probably not
There or numerous reason the compressor won't come on

your fan outside is running but the compressor is probably not
there or numerous reason the compressor wont come on

You are exactly right. The frustrating thing is that I paid for a AC company to come out and they tried to tell me it was a circuit board problem and that the compressor wasn't getting any voltage. They wanted to charge me for a new circuit board as well as the compressor. I checked the voltage myself and it was getting 24v when the fan is on. Now I have to wait 2 weeks to get a Sears to come out since I can't seem to trust anyone else. It is a Trane AC with about 8 years of service. Does anyone have any idea what this will cost? Will it be less than $1k or more?

You are exactly right. The frustrating thing is that I paid for a AC company to come out and they tried to tell me it was a circuit board problem and that the compressor wasn't getting any voltage. They wanted to charge me for a new circuit board as well as the compressor. I checked the voltage myself and it was getting 24v when the fan is on. Now I have to wait 2 weeks to get a Sears to come out since I can't seem to trust anyone else. It is a Trane AC with about 8 years of service. Does anyone have any idea what this will cost? Will it be less than $1k or more? if you have 24 v going to the condenser unit, did the relay for the compressor pull in.. Do you have power 208 v + feed to the condenser unit.. did they test to see if the compressor is bad...

There are many companies that would be glad to look at this for free and give you a quote. Call some places in your area, compare the estimates. You should be able to ferret out the BSer's. A compressor should last more than 8 yrs.

They didn't test the condeser. I will check to see if 208V feed measures OK. I would think so because the fan is going full blast and I hear the condenser motor start. The only thing the did was test the pressure to make sure there wasn't a leak. Unfortunately I wasn't home at the time they did 90% of their work. Thanks again for the help and suggestions.

Sounds like a classic situation where the compressor motor is not running, due to a faulty contactor (relay). Get it replaced and I bet your problem immediately goes away. Read my other postings on maintaining ACs.

24 VAC goes to the contactor's coil, which is controlled by your thermostat, and 220VAC goes to your compressor motor. The contactor points are probably shot and the compressor is not getting current.

How is the condenser fan getting current if the contactor didn't pull in?

Anytime I find a condenser fan motor operating and the compressor is not the first thing I suspect is a faulty compressor. It may be something as simple as a wire burnt off or something but it is usually a faulty compressor.