Residential A/C won't cool

Discussion in 'Shop Talk' started by mary,tx, May 12, 2005.

  1. mary,tx

    mary,tx Well-Known Member Supporter

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    The air conditioner won't cool the house! :waa: This is the first time this year we have tried to use it. It worked fine last year.

    The blower on the air handling unit works fine and will blow and blow. The thermostat is set to "cool" and the fan setting is set to "automatic". Both circuit breakers on the air handling unit are on. The circuit breaker outside that runs to the outside A/C condensor unit is on and I cycled the breaker just to make sure.

    Abnormal symptons are:
    The blower on the condensor outside does not run.
    The temperature of the copper tubing that goes between the inside and the outside is near ambient (i.e., not hot, not cold) meaning that the compressor not running.

    When I have the time, my next thought is to check both ends of the control cable that runs from the air handling unit to the outside A/C unit to make sure there is not a break in the wire somewhere (perhaps from mice) and also to check to make sure that the AC power reaches the outside unit. Perhaps I hope that the control cable is bad since the low-voltage DC wiring is something that can be easily fixed. What I don't want is to find out is that the compressor is bad or that there is a freon leak or there is a bad circuit board that I am unable to troubleshoot. What should I check?

    Thanks,
    Dale (DH of Mary, TX)
     
  2. gleepish

    gleepish Well-Known Member

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    We always check our cuircuts first... usually there is a breaker that flipped... maybe it's just that simple? Hopefully?

    Good luck!
     

  3. moopups

    moopups In Remembrance

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    Establish that the outside motor is getting currant via a test meter, carefull for you must test it when its hot. If there is currant present then the motor is fried or corroded to a point it will not run, or something can be jammed into something that should move but does not. Check for blockages with the currant off, manually try to turn the motor or parts attached to it. If the motor will not turn then it needs to be replaced, but thats a lot cheaper than a fried compressor.
     
  4. John Hill

    John Hill Grand Master

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    OK, lets think about this... the pipes are not hot which as you say indicates the compressor is not running. The blower on the outside condensor is not running either, now this could be because whatever stopped the compressor stopped the condensor fan too? Or maybe that fan never runs unless the condensor reaches a certain temperature, which it wont because the compressor is not running.
     
  5. agmantoo

    agmantoo agmantoo Supporter

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    Check the control voltage to the thermostat. Sounds as if the small transformer died.
     
  6. Hip_Shot_Hanna

    Hip_Shot_Hanna Well-Known Member

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    Yup look for fire ant damage they got in the TV antena junction box and the well pump junction box and shorted them both out.
     
  7. mary,tx

    mary,tx Well-Known Member Supporter

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    The A/C is now working! :dance: :dance: :dance:
    It was the control wire at the outside unit. The control cable had been quite weathered and some of the insulation was off with some bare wire. I cut off the bad section and pulled slack into box and made a new splice.

    Unfortunately, when I was cleaning up after myself and putting the cover back on, I discovered bare wire near the ground. I sprayed it with conformal coating to seal it for now and will run new wire later. Perhaps old weed trimmer damage there--probably before my time here since I do not do much string trimming and the damage looked old--a wonder it has lasted this long. I do pull weeds around the unit by hand that are too close for the push mower.
    Dale (DH of Mary, TX)
     
  8. 2story

    2story Well-Known Member

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    good for you! your low voltage line is 24 v AC not dc.