central-air cond.

Old 08-01-03, 07:51 AM
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central-air cond.

i have a friend with a central air that won't start, he turns thermostate on to cool, sets temp, but compressor dosn't start. i checked power to compressor it's fine, i all so manualy pushed in start contactor control ( out side on compressor panel) when i manualy pushed it contactor compressor starts and run fine untill i release it then it stops, is it poss. that the thermostate is ( on wall in side is not working right ) please advise thank you for your time and advice on what to do chet19472000
Old 08-01-03, 08:57 AM
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In order, I'd suspect the thermostat, the contactor coil, the transformer (for the thermostat), or the wiring. A couple of quick tests: Set the thermostat to heat and turn the thermostat up. If the furnace comes on, the transformer is good. Set the thermostat back to cool and jumper from common to cool on the thermostat. If the AC comes on, it's the thermostat. A DVM can tell you if the control voltage is getting to the contactor. If it isn't, check the low voltage wiring.

Old 08-01-03, 11:24 AM
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Location: NW atlanta
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i agree

with plainbill. i would also look to see if there is a low pressure switch inline at the outdoor unit. low charge may have it out.

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