No pleasure, no rapture, no exquisite sin greater... than central air

June 1, 2010 10:03 AM

My air conditioner has stopped...conditioning. I live in a condo on the north side of Chicago in an old conversion building. The furnace in my mechanical closet hooks to a AC unit on the roof, and for the last few days, it's been running full blast and can barely keep my unit below 80 degrees. I checked on the roof unit, and the fan is blowing cool air out. At this point, I'm pretty sure I need to call in a HVAC guy, but even the best reviewed places on Yelp are combinations of THANK YOU FOR SAVING MY LIFE and OMG SO OVERCHARGED. So, mefi, what do you recommend? If anyone here has any expertise in the field, I'd love to know whether you think this is something simple like a coolant recharge, or I'm looking at a new AC unit. My best guess is that the AC is about 5 years old, give or take.
posted by Oktober to home & garden (14 answers total)

sometimes the coils can get clogged from ice, formed in really humid air. try turning the unit off for 2-4 hours, and then restart it.
posted by lester's sock puppet at 10:08 AM on June 1, 2010

Shut it off yesterday (leaving the fan on) for over two hours, still no dice.
posted by Oktober at 10:09 AM on June 1, 2010

Assuming your condo building is professionally managed, call their office and get a recommendation for a reliable company.
posted by Short Attention Sp at 10:10 AM on June 1, 2010

Check to see if your unit is leaking fluid at all, and check to see if the filter is full. Ours just iced up for that reason, and it was an easy fix (replace the filter, turn unit off to let the ice melt, restart, voila!)
posted by lhall at 10:12 AM on June 1, 2010

FWIW, I like to take negative Yelp reviews with several spoonfuls of salt. People are often much more eager to go to the trouble to complain about something than they are to praise it.

But yeah, in theory your condo management should know someone.
posted by shakespeherian at 10:16 AM on June 1, 2010

I asked coworkers for HVAC recommendations when I first bought a house. Or ask your neighbors. Anyone who owns a home has likely dealt with this at some point.

Our central AC unit has a coolant leak and needs a couple pounds added almost every summer. It runs around $200ish each time, depending on how much coolant they have to add. We do have a maintenance contract with the HVAC company, though, so we get a slight discount.
posted by something something at 10:18 AM on June 1, 2010

We had a similar problem with our heat pump last week. Called up a local HVAC company and paid to have more coolant added to the lines. Made a world of difference. It cost around $200 but we needed A LOT of coolant.

Now, instead of running for 4+ hours and not cooling the house down, it cools the house down in less than 10 minutes.

You need to have sufficient coolant in your lines for the AC to operate efficiently. The cool air being blown OUTSIDE leads me to believe this is your problem, too. (that's what happened at our house)

Good luck!
posted by siclik at 10:21 AM on June 1, 2010

When our central air conditioning did this same thing, the problem wasn't at the air conditioning unit, but at the 'radiator' end that was inside our furnace. After years of lazy filter maintenance and being pet-owners, enough gunk had accumulated on the radiator to prevent it from cooling. See if that part needs cleaning first, but if the AC is running and the indoor-end isn't cold to the touch, then your problem is likely a lack of coolant.
posted by AzraelBrown at 10:47 AM on June 1, 2010

I find that Angie's List is far better than Yelp for finding various contractors, and your savings in money, time and aggravation will easily pay the cost of an Angie's List membership.
posted by iknowizbirfmark at 10:52 AM on June 1, 2010 [2 favorites]

If you do end up calling someone I've had good experiences with American Vintage for both hot water radiant and central air in my older house. They aren't the cheapest or the most expensive, but they're thorough, clean, on-time, and have done good quality work for me, from a small boiler repair to installing three radiators and a second heating zone. They're up in Evanston but do a lot of north side / north shore work.
posted by true at 10:53 AM on June 1, 2010

Just a quickie idiot check: is the compressor/radiator unit on it's own breaker? because mine is, and it had tripped, which let the inside blower run without providing any cooling. it only took 2 hours for me to check it, because why would that breaker ever trip? Normally, that would be an indication of trouble, but it hasn't happened again.
posted by ArgentCorvid at 12:14 PM on June 1, 2010 [1 favorite]

I'm not an expert, and have never dealt with remote roof unit. But if you have the time and inclination, here a few tidbits.
1) Regarding refrigerant, there should be a "sight glass" somewhere along the line, I think they're generally mounted near the compressor. In your setup, the compressor is likely up-top as well, because it throws off a lot of heat. If there are bubble in the glass, you're low on refrigerant.
2) There is likely a timer controlling the entire unit. This allows it to rise in temp. every so often, and avoid the previously mentioned ice. You may be able to check that this timer is running. The mechanical models are controlled by pins that screw into a plate which rotates past a switch. I've seen these pins work themselves loose, and then cause the timer to stick.

I've found that you get what you pay for re: HVAC work. I've hired people who charge anywhere from 60/hr to 125, and will never try to scrimp again. It might sound weird, but I think there are a lot of ways that a "normal joe" can assess a contractor.
Paper organization in their van (slots and clipboard hangers)
Use an 800 #
Return your calls promptly
Are timely for estimates
Are they busy (good people are in demand. My good guy is hard to get in the summer)
Do they have contracts, or are they purely on call

Obviously these type of things are subjective (maybe even unfair), but I am going to think thrice before hiring someone who answers the phone with "yeah?", shows up with a passenger side seat strewn with papers, and is available same-day.
posted by Jack Karaoke at 12:31 PM on June 1, 2010

I am not an HVAC expert, however, as a condo owner in the north side of Chicago, in a converted building, with an AC unit on the roof that is about 5 years old, I kinda know what you're going through. In my case, every Spring/Summer, the first time we turn on the AC, it will run and run without ever feeling cooler. Turns out, we have a very small coolant leak somewhere on the line, so we have a company* come out, top off the coolant and it's good for the year. I think they charge about $50 for 1lb of coolant (+ the fee for walking in the door, which I don't remember how much that is). That being said, for YOU, it could be a leak, it could be something else. You really should get a professional to check it out.

*unless I'm misreading this, your question was asking what could be wrong and didn't specifically ask for a recommendation, so to avoid sounding like a commercial, I omitted their name, but will gladly recommend them if you want me to.
posted by exclaim at 2:59 PM on June 1, 2010

Seconding checking the breaker. It is possible for the unit to be on it's own breaker. My unit ran but blew room temperature air. Flipped the breaker and...voila!
posted by zerobyproxy at 3:51 PM on June 1, 2010