Hi guys,

My AC isn't working - it was working a yesterday I think but it's been cooler these days so didn't really notice (been using the whole house fan more).

Today is hot. And noticed that the AC is not working. The outside unit is working (it seems; it turns on and the fan on top spins). I think the unit in the attic which blows air is not working. There is no air being pushed out the ducts.

Any ideas what the problem likely is? And how much will it cost to fix? I'll give an AC repair shop a call in the morning but would like to have an idea what I'm looking at first.

The AC is about 18 years old. I've just allocated a pretty penny for this solar thing so hoping to keep the AC alive for a few more years.

Unfortunately it could be a lot of things. But start with the filter, a dirty filter especially if it's a high merv will choke off airflow into the unit. If the compressor and fan outside are running fine it's prob not a capacitor, but those can fail and are an easy fix if you're careful. Also check the refrigerant lines outside, if they've iced up you're probably low on refrigerant, there's no way to check that yourself without a professional kit and the knowledge to use it.

Whatever you do don't keep it running if it's not cooling properly, depending on what's wrong it can cause significantly more damage.

My units are going on 20 years old, been through multiple capacitors, a circuit board or 2, and recently a metering valve that caused a loss of refrigerant. If it's not something easy and obvious like a blown capacitor or a dirty filter there's really not much an average homeowner can do to troubleshoot.

Check the breaker.

Thanks. Filter is replaced seasonally. The outside unit seems to be running fine. But no air is coming out of the ducts. Not sure how long it’s been like this. At most a day or so.

Reading the webs, sounds like maybe the blower motor and or blower cap is bad. $400-800 repair. I’ll take it if it keeps the system alive a few more years.

I checked the ac breaker next to the condenser. Is there another in the house main panel? I’ll go check.

hopefully you turned it off. If not your bill will be bigger.

Main panel breakers okay.

I turned it off this evening. May have tried running most of afternoon though

Your issue is on your unit inside (air handler). There is also usually a breaker ON the air handler, check it. Change the batteries in the thermostat, then check the air filter, then put it on fan ON and see if any air blows out of the ducts, go to the unit in the attic and see if you can hear the blower running, also can you physically see the coils on it, check that it isn't frozen over with ice....... My guess would be a bad blower motor, but could also be low freon causing the evaporator to freeze over, could also be something as simple as a fuse. Also shopvac the drain outside for good measure.

If the condensing unit outside is running, and there is no airflow because the air handler isn't coming on, the lines will ice over and doesn't necessarily mean it's low on freon.

quote:

Originally posted by jimmy123x:
Your issue is on your unit inside (air handler). There is also usually a breaker ON the air handler, check it. Change the batteries in the thermostat, then check the air filter, then put it on fan ON and see if any air blows out of the ducts, go to the unit in the attic and see if you can hear the blower running, also can you physically see the coils on it, check that it isn't frozen over with ice....... My guess would be a bad blower motor, but could also be low freon causing the evaporator to freeze over, could also be something as simple as a fuse. Also shopvac the drain outside for good measure.

If the condensing unit outside is running, and there is no airflow because the air handler isn't coming on, the lines will ice over and doesn't necessarily mean it's low on freon.

We had a similar problem a few years ago, turned out the coils were frozen and dirty. AC guy had to cut the lines to the coils, remove it, powerwash it and replace. Cost about $350.

You have the unit in your attic? The evaporator and blower part?

It should be sitting in some sort of pan and have a piece of pvc pipe (normally) that drains the water condensation away.

There's a good chance the drain is plugged up and the water can't drain. There is a float sensor thing that will shut the unit off if the water gets too high in the pan.

Go take a look at it. If you see water standing in the pan thing, see if you can see the drain to take the water away. Poke a bit of wire coat hanger in it, or whatever you can find, and get the water to drain away.

Or you might need to take some sponges, old towels, a cup, whatever, and empty what you can into a bucket. This would at least get it running for awhile so you can get a pro out.

If this is the case, and you get it running, you may need a AC guy, or a good handy man, to use a air shot blower canister thing that will blow out the drain pipe.

Oh, and if that's the case, look at where the pvc pipe drains to and see if you can get to the open drain end and see if it's clogged, and do what you can to unclog it.

I just had to fix this exact same problem, and issue, in my sisters house.

Good luck to you.
.

For all the "check the breaker", "change the thermostat batteries", "could be as simple as a fuse", "condensate float switch".... comments,
...the outside unit *is* running! Which means the low voltage transformer is supplying power from the indoor unit (means all that shit is fine).

Back to the blower not running:

Bad blower motor
Bad control board/relay
Frozen coil, not allowing airflow (check to see if suction line is covered in ice)

We had a pile of ants in a set of points or some such on the side of the coils outside. There were so many of them they had made a ball the size of a baseball.

Guy pulled a cover off and saw them. He blew them off with compressed air and cleared the dead ones out and it worked fine after that.

I make sure I hose any ants with Bifen now....We haven’t had a problem since.

Thanks guys. I'm suspecting bad blower motor or something related to that. Have AC repair coming out to take a look.

One of the first service calls I took in south Florida back when I did residential - found a troop of ants were marching across the compressor contactor and they were insulating the current flow and it couldn't run.

Pull the disconnect, blow electrical panel clear & hit the rest with wasp spray - Voila.

Homeowner wasn't super happy that I had him running within 15 minutes of showing up & the shop insisted that I bill - but the house was cool when I left.

quote:

Originally posted by soflaac:
...
Homeowner wasn't super happy that I had him running within 15 minutes of showing up & the shop insisted that I bill - but the house was cool when I left.

That's like the story of a guy who retired from a manufacturing plant. One of the machines went down, which was really screwing up their production. They asked him for a quote to come in and fix it. He quoted $10,000, which was a pretty good deal given the loss of production.

He came in, hit the machine with a hammer, and it started right back up. After invoicing, the company complained and wanted an itemized invoice. His itemized invoice:

Hitting machine with hammer - $10
Knowing exactly where to hit the machine - $9,990

AC motors/capacitors rarely last 18 years... If that's the culprit, you certainly got your money's worth out of it!

Look at the bright side, if you do have to replace it the new one will be more efficient, allowing you to run it longer without going over your solar power's ability to create credits!

Likely the motor, a relay, something in the handler, my fathers did this last week, the blower motor gave out. About a $400 fix.

If the drain was clogged up and the sensor activated I think it just shuts down the compressor but allows the fan to continue to run. At least mine does, I know the problem as the fans running for a long time and the temps are going up.

Doubt it's the drain.. still won't hurt to check...

quote:

Originally posted by HRK:
Doubt it's the drain.. still won't hurt to check...

Yeah, go check it... again... won't matter. While you're at it, check the stat batteries, breakers, fuses and check the contactor in the outside unit, you know, the one sitting outside which the OP stated was running!

Myself, I don't like running around in circles trying to fix something.

Still cost a pretty penny but less then it could have been.

System is still kicking but is starting to show signs of age. Maybe another 1-3 years left?

Had to replace 2 caps (condenser and blower side; condenser side was still working but it was a $50 adder to the cost to fix the initial problem so just got it out of the way; leverage the 'visit' cost). Blower motor seemed fine.

Igniter is getting crusty, need to look for part and replace.

Thanks for the help guys. Need to start thinking about a system replacement - what brand/model to get. And start saving up.

Be glad you didn’t need any refrigerant. R-22 is now $80 per pound and a full charge is on the order of 10 pounds. The new stuff is under $20 a pound.