Lennox G26 - need ignition module? No fan/LED - http://www.hvacmechanic.com/ Forums
Original message
| Peteo
 |  "Lennox G26 - need ignition module? No fan/LED"
, posted Mon 7 Jun 22:28  
I have a Lennox G26 furnace, and the other day I noticed the AC wouldn't come on...no fan would come on, no matter what I selected on the thermostat. Thermostat seemed ok, so I noticed the circuit was tripped. I turned the circuit back on and the blower and AC started right back up.
I got home from work and the house was 88 degrees inside, no tripped breaker, and no furnace, AC, or blower fan running. I look at the Johnson Control G776RGD-2 ignition module and see no LEDs lit. Does this mean I need a new module, or may there be something electrical that has gone bad that is causing this module not to operate? If i understand correctly, after leaving the power off to the G26 for a couple hours, and putting power back, I should get some sort of LED reading if the system is ok?
Any help is appreciated. Thanks!
Pete
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Replies:
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| HVAC Doc
| "Re(1):Lennox G26 - need ignition module? No f" , posted Tue 8 Jun 07:16
Check your fan control board (lower control board). Usually will have a big burn mark on the back. As Xen said, may also be transformer issue.
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| xenos
Webmaster 
| "Re(1):Lennox G26 - need ignition module? No f" , posted Mon 7 Jun 22:30
I would suggest that the transformer may now be defective.
Xenos.
The best way to escape a problem is to solve it.
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| | peteo
| "Re(2):Lennox G26 - need ignition module? No f" , posted Tue 8 Jun 13:34
Ok, the breaker on the side of the fan control unit was tripped. Before this go tripped, my electrical circuit breaker was tripped in my electrical box. I reset the circuit breaker on the control box and everything runs again. Is there a way I can tell if I have a bad circuit board, or transformer?
Pete
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| | HVAC Doc
| "Re(3):Lennox G26 - need ignition module? No f" , posted Tue 8 Jun 15:18
If you are talking a little black rocker style switch inside the blower access panel, that is the 24v. protection switch which means something somewhere is shorted/shorting and causing it to trip. This protects you from frying your transformer and possibly other components in the system (circuit boards, ignition controls, etc.).It means that a t/stat wire is shorting, connection is loose (inside or out) and shorting out, or a component on the low voltage side is shorting.
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| | peteo
| "Re(4):Lennox G26 - need ignition module? No f" , posted Tue 8 Jun 16:39
Got it...well, I burned up the transformer, so I replaced that... My furnace now runs, but i'm not seeing the a/c fan outside coming on. I traced the wiring out the AC unit and it goes to some sort of relay. I push this, the fan comes on, so i know it's getting power...but i'm just not sure what may be causing it to not trigger. Smells a bit like something burned up in the unit outside as well...just like the transformer smell...and it's coming from that relay device, i believe.
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| | peteo
| "Re(5):Lennox G26 - need ignition module? No f" , posted Tue 8 Jun 17:08
Pulled the door of the side of the external a/c unit and noticed a board, part # 47j35 that had a severely cooked diode in the upper left corner...
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| | HVAC Doc
| "Re(6):Lennox G26 - need ignition module? No f" , posted Tue 8 Jun 17:23
You will need the Lennox part number 47J27 which is a Fan/Timer circuit board. Might even find one of the old 47J35's around but haven't had the problems with the new ones like the old style.
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