A/C capacitor issue

Discussion in 'General Electronics Chat' started by dhaasis, Sep 16, 2012.

  1. dhaasis

    Thread Starter New Member

    Sep 16, 2012
    2
    0
    I am having trouble with my A/C unit. I have replaced the c/b and the unit will run 90% of the time but kick out the c/b 1-2 x/ day. could it be the capacitor? The control voltage is present and when I reset the breaker it will run fine for hours. The capacitor is a dual compressor/fan. 35 -5 MFD.

    any recommendations are appreciated.:)
     
  2. #12

    Expert

    Nov 30, 2010
    16,278
    6,789
    I recommend you hire a real repairman because your logic is nearly useless. Circuit breakers almost never get weak, but you replaced that first. Capacitors don't heal for a while when you reset the breaker, they stay bad, but that's your second attempt.

    You could try cleaning the condensor coil. If it's full of dust from summer lawn mowing, that will make the compressor work too hard. If that doesn't fix it, either buy a voltmeter and an ampmeter and quit guessing, or hire a real repairman. The money you save by not being safe can have a terrible cost.
     
  3. PackratKing

    Well-Known Member

    Jul 13, 2008
    850
    215
    Definitely clean / check the condenser coil.......especially those with the "Christmas garland " fins on the coils.

    I worked 8 years up to retirement in HVAC.....as a bench technician. The totally enclosed fan motors are usually sleeve-bearing, and a bare minimum at that. Some have a means of oiling, most don't . Fan motor bearings that are starting to dry up, will absolutely give you the electrical symptoms you describe. Repairing those motors once they start to fail, is virtually impossible, your only real option is a new one........sorry to say.

    I "inherited" a remnant of 2 mil fiberglass insulation sheet from a shop that makes custom insulation blankets for other industry. I keep a single layer of it taped [ double sticky ] on the outside of the condenser housing, to snag lawnmowing detritus and the early spring tree-fuzz.
    I've been told it looks " hillbilly " but I don't care, it works flawlessly, and the AC is ice-cold.
     
  4. #12

    Expert

    Nov 30, 2010
    16,278
    6,789
    Just a bit of extra information: the bottom 2 feet of the condensor coil catches most of the debris. Above that, it's usually fairly clean. When you flush it out with a garden hose (hose pipe if you're British) never use more pressure than you can generate with your thumb or you'll flatten the fins. Either be very careful or neglect to flush above 2 feet off the ground to avoid watering the fan motor. Fan motors don't like water!:(
     
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