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Old 04-20-2011, 11:18 PM   #1
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Central AC not working

My ac is not blowing cold air. Upon inspection, the outside compressor does not come on when I turn the ac on unless I press the compressor contactor. I have a question about wiring.

I have a control box mounted to the heater in the attic where all the connections are made. From the thermostat R G W are tied to R G W on the control box. Y and R from the gas valve are tied to B/C and X on the control box. From the contactor at the outdoor mounted condensor (split system), the red wire R is wirenutted to the yellow wire Y from the thermostat.

The white wire W from the condensor contactor is not attached to anything. The compressor contactor will not catch. I suspect because the white wire is not connected, it does not complete the circuit and therefore does not power the solonoid to hold the compressor contactor.

The name listed on the control box is "Central Environmental Systems" which I have found out is no longer in business. I am not an ac tech, but I do have an electrical background. However, I am unable to obtain schematics.

What should the white wire from the compressor contactor be tied to?


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Old 04-20-2011, 11:30 PM   #2
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It can be the condenser is not receiving the 24v or the contactor solenoid is open. AC was working so I think you should focus in your condenser first.



**Always kill the power ** Hot air rises, but heat will always move from higher to lower temperatures. ** Real man shoot in manual. ** If it ain't grounded, it ain't dead.

Last edited by JJboy; 04-20-2011 at 11:32 PM.
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Old 04-21-2011, 12:29 AM   #3
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Originally Posted by dyinginlasvegas View Post
What should the white wire from the compressor contactor be tied to?
common, b/c.
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Old 04-21-2011, 05:44 AM   #4
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Check for 24 volts at the control side of the contactor first.
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