Air handler will not blow

Discussion in 'HVAC' started by davvid20120, Mar 29, 2012.

  1. Mar 29, 2012 #1

    davvid20120

    davvid20120

    davvid20120

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    I have a Carrier air handler and a Bryant compressor/air conditioner about 6 years old that supplies cool or warm air to the second floor.

    When I turn on my thermostat to cool the air handler will not blow air. The compressor will come on and the evaporator coil and refrigerant lines are very cold. I can hear that faint noise that comes from the coil/refrigerant lines when you know it is working. If I take both breakers out at the air handler, wait about 5 minutes and then put breakers back in fuse box the air handler comes on.

    First time I did this, it blew for a few days, second time a day, third time until it reach the lower temp setting at the thermostat and now it comes on for a second and stops.

    I turn the A/C unit off at the thermostat, there was ice/frost building up on the coils. I have the fan set to 'on' at the thermostat. The air handler will come about every 10 minutes blow air for about 5 seconds then stop. I left the system set to fan 'on', and woke up in the morning to fan blowing constantly. Currently, the therm. set to A/C off and fan to on and the blower comes on.

    Model # for handler: FC4DNF036000AAAA
    Serial #: 3006A87948

    It seems like capacitor problem, but then blower will come on. I don't see a capacitor. The wires from the blower motor, 1 goes to circuit board and 3 others go to this thing looks like a chunk of metal. On those same terminals are wires that run to circuit board. Is this a sensor?
     
  2. Mar 29, 2012 #2

    paul52446m

    paul52446m

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    Your fan on speed is probably a different speed then the cooling. You will have to find the wires coming back from the blower to your electronic board , Find out what speed the cooling is on and check the power to see if you have 220 volts going to motor when calling for cooling, if you do
    then you could have a bad winding in the motor. If you don't have power it could be the small cooling relay in your electronic board, replace board. paul
     
  3. Mar 30, 2012 #3

    davvid20120

    davvid20120

    davvid20120

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    Cool. Thanks for quick reply. Does a bad winding mean I would need a new motor? About how much would that board be if the board needs replace?
     
  4. Mar 30, 2012 #4

    paul52446m

    paul52446m

    paul52446m

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    If you have a bad winding that would need a new motor. I have a service man that does all of your service and he also replaces all the parts so i do not keep up with the prices. Paul
     
  5. Mar 31, 2012 #5

    thermalmedics

    thermalmedics

    thermalmedics

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    along with that great advice I would rule out the thermostat and low voltage wiring issues.

    1. pull the thermostat cover off of the wall. touch red to green wires together. does the blower motor come on at all??

    does it stay on if you put a wire nut on them?

    if so than you have a bad thermostat. if not than yes I would say board and to check that you would need a meter. and like the good advice above. if you are getting 240v to the motor and the motor is not operating then it is bad. should be a run capacitor in there to check.

    I was just thinking you wouldnt have the intermittent fan motor if a winding in the motor was bad it would just die.

    I would check loose wires too. sometimes those wire plugs need a wiggle to tighten up. I would definately look there too.

    make sure to pull the disconnect before working with wires, capacitors, motors too here is a quick [ame="http://www.youtube.com/watch?v=ZHNOtquwtlM"]you tube vid on how to use it.[/ame] this is an outdoor disconnect so yours may be different at the air handler.
     
  6. Mar 31, 2012 #6

    davvid20120

    davvid20120

    davvid20120

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    thank you all for great advice. I will try this suggestions. I get one day off every two weeks, so when i get time I'm gonna do these things
     
  7. May 22, 2012 #7

    davvid20120

    davvid20120

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    Last night unit stop working. I took thermostat cover off and touch red to green. Nothing. With wires still touching I went up in attic and removed fuses and replace after 5 minutes, unit immediately came on.

    Looks like its the relay in the board. How do I check power going to the motor? Pull wire connection off touch with test leads
     

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