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Old 03-09-2013, 12:31 PM   #1
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Central air and heating turns on by itself

This may seem strange but it happens. I have central heating and cooling system in the attic. The thermostat is on the wall with a wire going up trhough the ceiling. I switched the thermostat to off and the settings of both blue heating and red air conditioning is all the way to the left or below 50 degrees. What happens is that once in a while the system goes on by itself. It blows cold air. I took the thermostat out taking the four wires out, thinking it was not working; but even then the system would go on by itself. So, I turned the breaker off at the panel board. Unfortunately, the same line is connected to the bedroom lighting. So, it is not the thermostat to blame. So, why is the system turning on by itself ? Can I put a switch somewhere so I can shut it off without disturbing the bedroom ? What is there in the motors assembly in the attic that makes the unit go on by itself ? Thanks for any advice.


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Old 03-09-2013, 12:36 PM   #2
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when you had the wires out of the stat did you let any of them touch?


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Old 03-09-2013, 12:38 PM   #3
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Inspect around your furnace for an air cycler.
It looks like a white thermostat.

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Old 03-09-2013, 12:39 PM   #4
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that or some raccoons/squirrels got into the attic and chewed some of the tstat wires. watched enough Billy the Exterminator shows to know that can happen. U may need to replace the wire from the tstat to the attic unit as it may have a short in it.
"Cut it twice and it is still too short".
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Old 03-09-2013, 08:46 PM   #5
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Does just the blower in the attic unit come on? How long does it run?
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