My girlfriend just called to tell me it's 79 degrees in the house. The AC's blowing out air that feels more or less room temperature. Is there anything along the lines of basic troubleshooting and simple fixes I can do to check it out before calling the HVAC repairman? The unit's about 4-5 years old, FWIW.

4/24/2009 10:51:25 PM

Check to make sure the lines aren't frozen wherever it connects to the air handler.

Mine did that very thing and it turned out my roommate had just turned down the AC system a little more than he should've and the lines froze. That unit was on the way out as well, but if the lines are frozen it's just a sign of one of the following:

1. You turned the temp down too much too fast.
2. Your outdoor heat pump/air conditioner needs its refrigerant recharged and needs to be checked for leaks.
3. Your heat pump/air conditioner is shitting the bed and needs replacement.

Also, if it seems like the unit is being tripped but the air conditioner/heat pump isn't kicking on outside, it might be worth checking the fuse box which should be right next to the unit. Should have some simple little fuses in there you could check with a flashlight.

[Edited on April 24, 2009 at 11:13 PM. Reason : ]

4/24/2009 11:07:54 PM

In addition to looking inside the outdoor condenser to check for iced up refrigeration lines, also make sure that the air filters are clean.

If the lines are iced up, you can de-ice them by running the heat for a few minuets. If they ice up again, you need to call a service technician. Low refrigerant is the most common cause. Make sure the tech puts in the time to find and repair any leaks if the refrigerant is significantly low.

Quote :

"1. You turned the temp down too much too fast."

If things are working properly, this should never be an issue. However, don't expect your house to get down to 55 degrees on a 95 degree day.

4/25/2009 12:13:42 AM

^ Things weren't working properly, but they were working enough when this happened at my apartment.

I had a full on snowman in my air handler. There was a massive amount of ice covering the entire air filter. The lines leading into the unit were frozen as well. It worked for a while after that once I let the thing thaw out though, lol. Thank god we had a home warranty on this place.

4/25/2009 11:03:48 AM

mine's doing the same thing, spookyjon

i think the A/C dude is gonna be rocked on monday

4/25/2009 2:23:14 PM

sounds like the ac is messed up

4/25/2009 8:35:12 PM

Listen to see if the compressor is running. If not, its probably your hard-start (a big ass capacitor). If you pull it out (mark all the wires so you can reconnect the replacement), you can take it to a plumbing supply store and buy a replacement for ~30 bucks.

Much cheaper than spending 85 bucks just for the guy to come out and then charge you on top of that.

4/25/2009 10:29:22 PM

79 is just about perfect.

4/25/2009 11:43:11 PM

^ Agreed. I keep it about 78-79 in this apartment during the summer. It feels nice to walk in on a 96 degree day and not go "holy fuckballs why is it so cold in here". Makes it easier to transition to outside temps too on the worst days. Plus, your electricity bill isn't bad and you're not working the AC unit to death.

I understand some folks are hot natured though and can't freaking stand warm temps.

4/26/2009 12:23:39 AM

i was playing golf yesterday when the fiance called to let me know it was 90 in our apartment. it was 5 degrees cooler outside the a/c was blowing warm air

4/27/2009 8:53:16 AM

Haha, exact same problem here

4/27/2009 8:55:13 AM

Quote :

"I keep it about 78-79"

wtf is wrong with you. 72 i could say ok that's reasonable..maybe even 74. but basically 80 inside is ridiculous

4/27/2009 8:56:50 AM

don't let the a/c run on low refrig. some units have a low pressure switch that will cut it off, thus preventing damage, some don't. don't gamble. my new unit didn't have one and it killed the compressor. fun times.

if the unit ices up and you don't have it turned to 60degF, then let it defrost and wait for the repairman.

Also, Solinari is right, if you don't hear the A/C kick on, then a few things could be wrong:

-breaker outside or inside has been tripped.
-hard start cap. is dead (happens a lot when it's hot) - cheap part if you can find a replacement.
-power is out.

[Edited on April 27, 2009 at 9:53 AM. Reason : r]

4/27/2009 9:51:53 AM

this happened to a friend of ours when he came home from work yesterday. it was so hot this weekend that everyone froze out their AC units

i feel bad for the HVAC guys today!

4/27/2009 10:02:56 AM

the worst part was yesterday was the first day since last summer we had even turned on the a/c, and we only had it on like 75. it never blew cold. i guess it's got a small refrigerant leak. oh well. this is the only time i'm glad i rent instead of own - when shit breaks.

[Edited on April 27, 2009 at 11:03 AM. Reason : .]

4/27/2009 11:02:25 AM

Quote :

"i feel bad for the HVAC guys today"

Don't. Business has been slow. They'll be glad for the work.

4/27/2009 11:26:23 AM

Quote :

"wtf is wrong with you. 72 i could say ok that's reasonable..maybe even 74. but basically 80 inside is ridiculous"

Have you all ever tried letting your bodies slowly acclimate to more efficient, seasonally adjusted temperatures instead of mandating a perfectly consistent year-round indoor temperature?

It's really quite easy, and it makes the outside weather feel more tolerable. I keep it at about 68 in the winter and 78 in the summer. I still haven't turned on my AC, lol. Just open up the windows at night and let the cool air in, then close up the window and keep the sunny-side blinds closed up to keep the sun out as much as possible.

4/27/2009 11:37:24 AM

^ yea i have been in Brazil for awhile now and have gotten acclimated to heat with no a/c just fans. Hopefully when i get back to the US I will be able to keep it like that but with the shitty/crazy NC weather i doubt it.

4/27/2009 11:43:39 AM

^ Yeah, I'm not banking on doing this forever. The AC is set to kick on at like 81 or so, and I'll turn it down so it kicks on once it reaches 80 in here.

4/27/2009 11:53:37 AM

If the unit isnt blowing out cold air, turn the thermostate to OFF and the fan to ON

As others mentioned, it could be low refrigerant. Low refrigerant means that the compressor circulates the freon (or whatever you have) more through the system, has less time to induce thermal transfer (pull warmth out of the air), and as a result makes the freon much colder than it is suppose to be. When the hold air gets colder, moisture comes out, and when the freon is too cold, it will cause your coils to start to freeze. This will reduce airflow, and the compressor will start to have a hard time pumping the freon through.

when this happens, if you allow it to stay like this for too long, will ruin your compressor. Your coils are probably already ruined if there is a leak (you shouldnt run low on refrigerant in a proper system). Coils arent easy to fix. I would expect 800-1500 for coils to be installed. If the compressor is hosed, it would be another 800-1500.

Bottom line... turning the fan on, cuts off the compressor, and blows hot air over the coils. Once you let the fan run for 6+ hours, the coils should be good, and you can attempt to turn the unit back on again to see if you get cold air. If you do, then you'll probably still need an HVAC guy, but at least you can cool the house a bit before it freezes over again.

4/27/2009 12:06:51 PM

^ You can just turn the system to heat and the coils will unfreeze in a minute or two. You're right about calling a service tech for a system that repeatedly freezes up.

4/27/2009 1:08:13 PM

lol, yeah, turning the heat on works a lot better than running just the fan. 1-2 hrs is much much better than 6. we used to have this problem with our ac unit at the beach all the time, then hurricane ophelia took it away so it's not an issue anymore

4/27/2009 1:30:58 PM

yeah see, we had the fan running earlier in the day just to circulate air w/the thermostat set to off. so i really don't see any way the coils are frozen up unless they did it instantaneously when i finally kicked the t-stat over to "cool".

[Edited on April 27, 2009 at 1:38 PM. Reason : n]

4/27/2009 1:37:30 PM

Well, turning to heat sounds great IF you know its the coils that are frozen. If it isnt, then you are going to have a hot house, with no way to cool it back down.

4/27/2009 2:30:47 PM

open the windows and turn the fan on

4/27/2009 2:35:06 PM

Quote :

"I keep it at about 68 in the winter and 78 in the summer. "

That's me. Also, keeping the humidity out of the house is more important than reaching a certain temperature for me, so sometimes I'll go below 78 when it isn't warm enough outside to trigger the system often enough to get the humidity under control.

I should probably just look into getting a decent dehumidifier - but if it costs just as much to run that than it would to just tick the thermostat down a degree or two, why bother?

Oh, I had to replace my everything 2 summers ago. Basically what people have said here. Slow leak, no refrigerant, fried compressor, new unit.

[Edited on April 27, 2009 at 10:41 PM. Reason : -]

4/27/2009 10:40:28 PM

lolz at all the shitty advice in this thread, if anyone wanted real answers they'd post in the garage

4/27/2009 11:01:13 PM

no they wouldnt you douche, because people like yourself would probably troll up their threads

4/27/2009 11:03:02 PM

make sure the condensate line isn't clogged and backing water into the pan under the coil. there's a switch there that will kill the compressor if this happens. it'll be obvious, there will be a shallow pan (1-2") under the indoor unit...just check to see if theres water standing or if there's a float switch that's stuck in the up position.

4/27/2009 11:48:31 PM

Quote :

"but if it costs just as much to run that than it would to just tick the thermostat down a degree or two, why bother?"

it doesn't, but it's a reverse a/c regardless.

[Edited on April 28, 2009 at 9:06 AM. Reason : house has to be well sealed to make a difference.]

4/28/2009 9:06:00 AM

^^ If that was the case then the fan wouldn't even cut on to recirculate air.

4/28/2009 2:12:33 PM

Before all else...the absolute easiest thing you can do:

While your shit is running, go outside and see if the condenser unit fan is spinning. It's the fan in the damn unit outside, the one you used to pee in all the time as a child.

If it's not spinning, is the compressor making its grrrrrrr running noise? If not, are the damn fuses still in the local switchbox or did some punk steal the damn things? Is a breaker in the house tripped?

Look for the simplest obvious shit first. Then go looking for the damn snowman in your evaporator coils or plugged up condensate drain/tripped safety switch.

4/28/2009 3:02:39 PM

hvac dude came today while i wasn't at home (i rent). said something about it being the condenser fan, that it was stuck (i don't think he said frozen) from not being used all winter. whatever the case, it's supposedly fixed.

4/28/2009 3:14:58 PM

^ That's good. Those fans are fairly cheap.

4/28/2009 4:06:42 PM