AC not blowing

Discussion in 'HVAC' started by katiekins, Jul 20, 2010.

  1. Jul 20, 2010 #1

    katiekins

    katiekins

    katiekins

    Member

    Joined:
    Jul 20, 2010
    Messages:
    6
    Likes Received:
    0
    So this afternoon I realized it is not blowing out. Its taking in at the intake site, but not blowing anything out of the vents. Our house is only 5-6 years old. We have lived here maybe 4. We've never had any problems with the AC, so never done anything to it. Outside coils look fine. Have not been upstairs. Breaker is fine. Any ideas?
     
  2. Jul 20, 2010 #2

    oldognewtrick

    oldognewtrick

    oldognewtrick

    Administrator Staff Member Admin Moderator

    Joined:
    Jul 26, 2009
    Messages:
    10,811
    Likes Received:
    1,433
    Katiekins, first off welcome to House Repair Talk.

    Now why are you so sure that the unit is pulling air? Is there a lot of ice on the condensor coil? Do you have duct work in a crawl space that an animal may have gotten to and chewed a hole in a trunk line. A little more info would be appreciated. Feel free to post pics of the unit and ducting.
     
  3. Jul 20, 2010 #3

    katiekins

    katiekins

    katiekins

    Member

    Joined:
    Jul 20, 2010
    Messages:
    6
    Likes Received:
    0
    I didnt see any ice at all on the coil. Right before I noticed it went out I felt it pulling air at the site of the intake. No everythings in the attic. I dont think anyones been up there at all for months. I just went up there, and i dont really know what to look for. Its a Trane . I can post pics what else would be helpful?
     
  4. Jul 20, 2010 #4

    katiekins

    katiekins

    katiekins

    Member

    Joined:
    Jul 20, 2010
    Messages:
    6
    Likes Received:
    0
    I might be wrong about the pulling air, I mean im not a handy woman or anything. LOL. But its 85 in here, and its hot. Any suggestions about what i could do would be great, thanks :)
     
  5. Jul 20, 2010 #5

    katiekins

    katiekins

    katiekins

    Member

    Joined:
    Jul 20, 2010
    Messages:
    6
    Likes Received:
    0
    thanks for the welcome btw :)
     
  6. Jul 20, 2010 #6

    inspectorD

    inspectorD

    inspectorD

    Housebroken Staff Member Admin Moderator

    Joined:
    Dec 17, 2005
    Messages:
    4,502
    Likes Received:
    267
    When is the last time the filter was changed on the unit in the attic...where nobody goes?

    Look for a small panel that can come off near where the ductwork and unit meet.
    How to change furnace filter - Filters America.com
    Try this site or google your own, and hope this helps.
     
  7. Jul 20, 2010 #7

    gatorfan

    gatorfan

    gatorfan

    Well-Known Member

    Joined:
    Mar 10, 2010
    Messages:
    56
    Likes Received:
    0
    Sounds like you have a split unit with a compressor outside and an air handler in the attic. If your compressor is running, your thermostat is correctly calling for cool, so that's probably not the issue. My guess is there's a dedicated breaker for your air handler that has tripped, disabling it. Note that there may be two breakers just for the air handler (and a third for the compressor)-- mine has one in the panel and an extra one in the attic, mainly meant as a maintenance shutoff I believe.

    You might also check to see if the overflow pan below the air handler has water-- in so, there should be a sensor that's detecting this and disabling operation. In my case there are two sensors, a flow sensor on the overflow valve and a float sensor on the bottom on the pan. I know this because one recently went bad and disabled my a/c too. I had to pull them out of the circuit to get things going-- got a replacement ASAP, but I was willing to risk an overflow to get some cool air!

    Matt
     
  8. Jul 20, 2010 #8

    katiekins

    katiekins

    katiekins

    Member

    Joined:
    Jul 20, 2010
    Messages:
    6
    Likes Received:
    0
    Changed filter last week. Yes we do gator have the split unit. We turned fan on and it wont run outside. We checked breakers and nothing, flipped them back and forth just in case. Still not coming on
     
  9. Jul 20, 2010 #9

    katiekins

    katiekins

    katiekins

    Member

    Joined:
    Jul 20, 2010
    Messages:
    6
    Likes Received:
    0
    fan wont even come on
     
  10. Jul 20, 2010 #10

    gatorfan

    gatorfan

    gatorfan

    Well-Known Member

    Joined:
    Mar 10, 2010
    Messages:
    56
    Likes Received:
    0
    OK, let me make sure I understand what's going on. First, a few notes. The outside unit does not have any connection to air blowing or not inside, it unit just receives the coolant, removes heat from it, and sends it to the air handler in the attic. The air handler in the attic has the fan which circulates air in your house-- it passes the air over over pipes filled with coolant (vast oversimplification) chill the air. The "fan" on the compressor outside just pulls outside air through the outside unit only-- it doesn't do anything to inside air.

    OK, troubleshooting steps.

    If you turn the a/c as low as it will go and leave the fan on auto, what happens on both the outside unit and the inside unit? You may need to leave it there for up to five minutes before anything happens due to built in delays. If the outside unit fan comes on, that means the compressor has power and is receiving the cool signal correctly. If not, it doesn't matter what the inside unit is doing, and you probably have a power problem on the compressor or a bad thermostat (or control wiring). Depending on how the wiring is set up, you might also have a bad sensor as I mentioned in my first post, but that's a tricky one to diagnose w/o a multimeter.

    Next step, if the compressor outside (fan) turns on but the air handler in the attic isn't blowing at all, leave the thermostat set to max cool and turn the fan to "ON". This will circulate air no matter what the temp. If no air still blows, there's probably a power problem to the air circulator.

    If air blows but it never gets cool, there's a problem in your coolant system and you'll definitely need a HVAC tech to resolve. I'm still thinking there's an extra breaker somewhere that's tripped. I'd go up in the attic and see if you can find one. Take a look at your overflow pan too while you're up there to make sure it's not full. If your condensation line is clogged, that can lead to an overflow which then leads to a shutdown.

    Matt
     
  11. Jul 20, 2010 #11

    gatorfan

    gatorfan

    gatorfan

    Well-Known Member

    Joined:
    Mar 10, 2010
    Messages:
    56
    Likes Received:
    0
    Just noticed that you flipped the breakers. There's usually a delay on the compressor to keep it from turning on and off too much. If you cycle the power, you'll have to wait for the delay to expire, even if the thermostat is calling for cool. They're usually less than 5 mins, but it can fool you into thinking it's broken if you're impatient. :)

    Matt
     
  12. Jul 20, 2010 #12

    handyguys

    handyguys

    handyguys

    Well-Known Member

    Joined:
    Feb 22, 2008
    Messages:
    815
    Likes Received:
    2
  13. Jul 20, 2010 #13

    kok328

    kok328

    kok328

    Well-Known Member

    Joined:
    Nov 20, 2007
    Messages:
    2,755
    Likes Received:
    249
    Do you have basic hand tools and a volt meter?
    If so, I can walk you through step-by-step troubleshooting procedures.
    First one is quiet simple: Do you have a digital thermostat with a LED display and is the display showing temps?
     
  14. Sep 18, 2010 #14

    knownothingknowitall

    knownothingknowitall

    knownothingknowitall

    New Member

    Joined:
    Sep 18, 2010
    Messages:
    1
    Likes Received:
    0
    I know i am 2 months late in replying but just came across this might help some one else in the future.

    If everything else is working but the fan outside with the coils is not it could be that it is low on coolant or a capacitor has blown. If a capacitor goes bad the top of it normally gets deformed (mushrooms) pretty easy to tell but looking at it, it's perfect or it's not. It should have like 3 wires going to it and looks like a soda-pop can.

    Cut all power and be very careful as this is high voltage. The capacitors act like a battery and store a charge. Cost to DIY is from $5-$50 and you can replace it in about 5 minutes.
     
  15. Sep 19, 2010 #15

    kok328

    kok328

    kok328

    Well-Known Member

    Joined:
    Nov 20, 2007
    Messages:
    2,755
    Likes Received:
    249
    knownothingknowitall, not all capacitors are shaped like a soda pop can. They can deform when they go bad and some will swell up around the sides and possibly leak. Not all capacitors will have three wires, some will only have two wires and in an HVAC system this means that there are two capacitors not one. In all my days, I've never seen a capacitor hold a charge especially if they are bad and/or the power is off however, yes, caution is advised.
     

Share This Page