Central Air

Old 07-14-03, 10:57 PM
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Question Central Air

Well my CA died today, I have checked the motor by direct wiring and it ran ok, I also replaced the thermostat with a spare, would it be correct to assume this is a relay problem? and is thier anyway to trouble shoot/test out this relay to see if it is in fact the problem...the relay is a good 15 years old, Thanks!(but the new CA unit is only a year old)
Old 07-15-03, 09:04 AM
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are you saying

that the indoor fan will not run on call from tstat, but will when straight wired? if so, probably is the relay
Old 07-15-03, 12:50 PM
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Three motors are in operation when the CA is cooling the house- (1) the compressor motor which compresses the vapor from the evaporator to a pressure with an equivalent temperature 30 degrees higher than the out-door air surrounding the condensing coil.(2) the condensing fan motor which circulates the out-door air across the condensing coil ,causing the vapor in the coil to condense back to a liquid. (3) The blower-motor which circulates the interior air across the evaporator coil with the result that the liquid refrigerant in the evaporator coil absorbs the heat in the interior air and evaporates into a vapor.

You have implied that your problem is the blower-motor which is switched On by a fan-relay. Is this inference correct?
Old 07-16-03, 10:55 PM
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Unhappy AC Fixed...

and I'm kicking myself, the fan only switch in the furnace is not used, their is the fan only on the Stat, after checking the motor I replaced the Stat and it was a no go. Had the plumber out today who thought it might need a hard start kit...on the phone, well guess what, it was the stat! Problem was their is a delay setting that was set at 5mins and didn't wait that long, just hooked it up and flipped it to AC and nothing, so I thought it was the relay. When the new stat was reinstalled today the jumper was changed to 2 min delay. This is a case of not reading the instructions. So it cost me $60.00 to have this all checked and the stat replaced that I had installed/uninstalled myself.

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