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new member

0 post(s)
posted on 10/6/2007


Any ideas on this problem?  My furance was "dead."  No LED, and the circuit breaker on both the house and the unit was blown. When I checked the transformer on the furnace is smelled bad and the inside was black.  I opened it and much of the copper wire was fused and damaged.  I replaced the trasformer, and the LED came on so I thought I was okay.  But when I turned on the thermostat the circuit breaker on the wall tripped and the same thing happened: the transformer "blew up" and now the LED won't light anymore.  I am thinking of replaceing the control box the transformer is going into (the one that also connects to the thermostat upstairs) and then putting yet another transformer on as well.  Does anyone have any thoughts on this?  What is causing my transfomer to fry itself?  I can't seem to see very many electrical parts in the furnace in general...the only thing I can think of is that it is someone related to that "brain" and that replacing it will solve the problem.

Thanks for any help!

Replies [ post reply ]

senior member

31 post(s)
replied on 10/8/2007

Replace the transformer - but install a 3 amp fuse on the 24 volt side to protect the transformer. one way to check for a short is to use a continuity tester on the R side to ground. if it is intermittant look for foil tape or insulation touching a limit ot check the limit housings. let know how you make out



junior member

10 post(s)
replied on 10/8/2007

you will need to do some isolating. I would try wiring the blower direct and see if that will run. The only thing that will usually smoke the transformer like that is a direct short.

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