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 Repairing and Servicing Lennox Products
 Repairing / Servicing Lennox Gas Furnaces
 Fan Relay Test Procedure
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tgrill

3 Posts

Posted - 06/10/2008 :  10:49:42 PM  Show Profile  Reply with Quote
Is there procedure to test a fan relay? I'd like to confirm that my P-8-10283 relay for my G14Q3-60-1 Pulse furnace is bad before replacing it. My P-8-9490 transformer fried when I turned my thermostat to cool. I've checked for shortages in the wiring, but have found none which leads me to believe it could be the relay.

Cozy.Support

5739 Posts

Posted - 06/11/2008 :  07:21:19 AM  Show Profile  Reply with Quote
Just use an ohm meter or continuity tester to test the N.C. connections. Then energize the relay to test the N.O. connections. This is not a 100% indication that the relay is good, because pitted/burned contact point may make connection one time, and not the next.



Cozy.Support does not provide a diagnosis for users of this forum. We do, however, try to provide information that will help servicers arrive at their own diagnosis.

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tgrill

3 Posts

Posted - 06/19/2008 :  10:59:16 PM  Show Profile  Reply with Quote
While testing the relay I noticed that there was continuity between the two wires in the AC compressor control cable (i.e. the wire pair connected to the AC compressor contactor). I did this test with the wire ends removed from the low voltage terminal strip in the furnance (i.e. eliminating any furnace connections). Is this normal or could there be a short in this cable that could have caused the transformer to fry?
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Cozy.Support

5739 Posts

Posted - 06/20/2008 :  11:48:11 AM  Show Profile  Reply with Quote
If you are sure than you have both ends of the thermostat cable disconnected, you should not measure any continuity between the wires.



Cozy.Support does not provide a diagnosis for users of this forum. We do, however, try to provide information that will help servicers arrive at their own diagnosis.

Once you know what part you need, you can contact the Cozy parts department by using the link below
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tgrill

3 Posts

Posted - 06/20/2008 :  4:15:44 PM  Show Profile  Reply with Quote
Just to be clear, the cable I'm testing is a single pair wire that terminates on the same low voltage terminal strip as the thermostat on one end and the AC compressor contactor on the other end. When I disconnect the wire pair from the terminal strip end only(i.e. eliminating any contact with the thermostat, leaving the connection to the AC compressor contatctor in place) there is continuity between the two open wires. Just to confirm, are you saying this should not be the case?
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Cozy.Support

5739 Posts

Posted - 06/20/2008 :  4:24:49 PM  Show Profile  Reply with Quote
If you you leave the contactor coil connected at one end, and measure the resistance with a VOM between the two conductors at the other end of the thermostat wire, you will get continuity, but it should not be zero ohms. The contactor coil will have resistance.



Cozy.Support does not provide a diagnosis for users of this forum. We do, however, try to provide information that will help servicers arrive at their own diagnosis.

Once you know what part you need, you can contact the Cozy parts department by using the link below
http://www.cozyparts.com/Lennox-Parts/locator_form.aspx

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