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Heat pump start cap went bad. replaced and when unit turns on compresser hums-won't start. push contacter in and it stats fine. it's a two speed. ?

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The reason the compressor starts when you push the contactor in is that you have an "open" in your control voltage. I would suspect that the thermostat was bad - since that is 'usually' the only component you have in that circuit.

Since you indicate this problem 'surfaced' after you had the "start cap" replaced - I might be suspicious of the new start cap and how it's wired in - but "assuming" it is correct I would probably change the thermostat.

Note: as with any Air Conditioner - when you start 'changing parts' you run the risk of changing out a perfectly good part (thus wasting perfectly good money) - so - if possible I would see if I could find someone to electrically trouble-shoot the AC to determine 'exactly' what was causing the problem.

hope this helps

Posted on Jul 29, 2010


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