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I have a Nordyne E2EB-015HB that isn't working. I use only the furnace, no cooling. The unit worked fine last year, but this spring we had a lightning strike that wiped out a bunch of electrical stuff. I knew it got the thermostat (Hunter programmable) so I replaced it. When I cycle the heat to come on, it blows the 3 amp fuse on the 24 volt circuit. The white wire on the thermostat is connected to the "W", the green to the "G", the red to the "RH", the blue to the "RC". These colors correspond in the furnace except the blue wire which connects to gray at the furnace. I checked the contactor coil (621909) impedance, it reads 10.9 ohms. This seems low to me. Could this be the problem, or should I check elsewhere? I also checked the fan control relay for continuity. On the heat side the switch to the fan is closed, on the cooling side it's open. Not sure how to check impedance on the 24v side.

Thanks for any info/advice,

Gary

Did you check to see if you were getting 24V output at the transformer?

Robert will probably be back on later with some more helpful advice. At the moment he's ducking tornadoes (literally!)

Mark

Thanks for the quick reply,
Yeah, checked the 24V, it's good. I'm getting a short across the 24V system somewhere. I checked all the wiring for skinned places, etc... but didn't find anything.

Thoughts and Prayers for Robert!


Gary

Hi Gary,

Thanks for the thoughts and prayers, we were blessed once again, but there were some injuries in surrounding areas.


The quickest way to find fault, is start with transformer, make sure you have 24-28vac at secondary side.


Then follow wiring diagram and circuit and jumper or remove each component to take out or by pass 24volt side.

As soon as you can get unit to operate without something, but not with it, you have your problem.


At t-stat, set to OFF and Fan ON, does it work ?


Set to Cool/Fan ON and set temp for a/c?


Set to Cool/Auto and set temp ?


Set to Heat/Fan ON and set temp ?


Set to Heat/Auto and set temp ?



Did it blow fuse, if so, which scenario ?




IF it does this ONLY in HEAT/AUTO, remove RED and WHITE wires and tie/jumper together seperate from t-stat, does it still blow fuse ?




Thanks,
Robert

Thanks, will check these scenarios to see which one(s) cause the fault. I'll let you know my findings.

Glad you & yours were safe. Our prayers are with the ones injured.

Thanks,
Gary

Hi Robert,

Thanks again to you and Mark for the quick response and the advice.

I found out the controller coil and the A/C blower relay were both bad causing the overload.

I replaced the controller and both blower relays and everything is working fine now.

Have a good weekend,

Gary

Hi Gary,

You're very welcome, glad it is good to go.



Thanks,
Robert