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-   -   ac compressor running without blower/thermostat won't turn off compressor (http://www.diychatroom.com/f17/ac-compressor-running-without-blower-thermostat-wont-turn-off-compressor-160512/)

cphaller 10-18-2012 09:07 PM

ac compressor running without blower/thermostat won't turn off compressor
 
Hi! I'm hoping to get some help with my girlfriend's ac unit before having to call a tech out. I noticed today that the compressor on the outside unit was running but the blower was not pushing any air inside the house. The temperature was set to 76 on the thermostat and was 76 in the house, so that was good. I set the temp down to 74 and the the blower came on and was pushing air through the vents, also good. I set the thermostat to 'off', which turned off the blower, but the compressor was still running and did not turn off at all. At this point I have shut the unit off at the breaker to avoid possible future damage. I made my way to the roof and there was significant ice build up in the unit. I opened the service panel and the checked the contactor, which looked fine. I had my girlfriend turn the breaker on and off and the contactor moved in and out like it should, so its not stuck closed. Wires from the thermostat to the board on the unit look fine and are wired correctly. I am thinking it is just a bad thermostat, but before making a run out to pick up a new thermostat I want to see if there are any other quick things I should be checking. Any ideas are greatly appreciated!

ben's plumbing 10-18-2012 09:38 PM

Quote:

Originally Posted by cphaller (Post 1033626)
Hi! I'm hoping to get some help with my girlfriend's ac unit before having to call a tech out. I noticed today that the compressor on the outside unit was running but the blower was not pushing any air inside the house. The temperature was set to 76 on the thermostat and was 76 in the house, so that was good. I set the temp down to 74 and the the blower came on and was pushing air through the vents, also good. I set the thermostat to 'off', which turned off the blower, but the compressor was still running and did not turn off at all. At this point I have shut the unit off at the breaker to avoid possible future damage. I made my way to the roof and there was significant ice build up in the unit. I opened the service panel and the checked the contactor, which looked fine. I had my girlfriend turn the breaker on and off and the contactor moved in and out like it should, so its not stuck closed. Wires from the thermostat to the board on the unit look fine and are wired correctly. I am thinking it is just a bad thermostat, but before making a run out to pick up a new thermostat I want to see if there are any other quick things I should be checking. Any ideas are greatly appreciated!

shut off switch to unit open thermostat and remove the wire on the y terminial...see if outdoor unit stops after you power back up...that controls the outdoor contactor for a/c...ben sr

REP 10-19-2012 05:17 PM

I can't imagine its the stat,but if it is then please don't get a cheap copy.Get a Honeywell or a White Rogers.It might be a heat pump with the defrost acting up.

ben's plumbing 10-19-2012 05:51 PM

hey rep I guess we have to wait for op to get back to us....must not be that important ...ben sr

cphaller 10-19-2012 06:13 PM

Hey guys thanks for the suggestions. So I waited for the condenser to thaw and tried pulling the y wire. And the compressor is still powering up with the thermostat set to off. I'm thinking there is a bigger problem.

ben's plumbing 10-19-2012 07:26 PM

Quote:

Originally Posted by cphaller (Post 1034150)
Hey guys thanks for the suggestions. So I waited for the condenser to thaw and tried pulling the y wire. And the compressor is still powering up with the thermostat set to off. I'm thinking there is a bigger problem.

ok now pull the the wire off y terminial on control board..... see if it stops...if not check contactor in a/c unit may be a bug got zapped in contactor and its stuck... or bad 24 volt coil for contactor....ben sr


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