I am experiencing a pretty complicated electrical issue with a GMT115-5A natural gas furnace. Unfortunately I live in a pretty remote area as far as HVAC service providers are concerned so I am 100% on my own to get my furnace fixed. Therefore professional help is not an option.
Furnace was working 100% until the control board failed. Now that it’s been replaced the board is killing the signal to the gas valve after about 6 seconds. Replaced the flame sensor twice and ran a dedicated ground but it still cuts out.
The board is outputting 107vac and I’m seeing the same voltage at the flame sensor tip. Everything I’ve tested is indicating a good ground.
The troubleshooting flow chart that came with the new board indicates this issue to be either a faulty (or dirty) flame sensor or a “bad grounding of transformer secondary). I am pretty confident I have eliminated the flame sensor as the culprit and I am pretty sure the transformer is properly grounded, but to double check what is the secondary of the transformer?
I have gone over the schematics for the new control board many times over and everything is correct. Could it be possible the new board is bad right out of the box? The new board is not 100% identical to the original but it is a universal that is supposed to work.
Could a dirty burner tube or incorrect gas pressure setting cause this issue? All six burners ignite no problem but something in the boars cuts the voltage to the gas valve after about 6 seconds.
thank you for all of the help
Furnace was working 100% until the control board failed. Now that it’s been replaced the board is killing the signal to the gas valve after about 6 seconds. Replaced the flame sensor twice and ran a dedicated ground but it still cuts out.
The board is outputting 107vac and I’m seeing the same voltage at the flame sensor tip. Everything I’ve tested is indicating a good ground.
The troubleshooting flow chart that came with the new board indicates this issue to be either a faulty (or dirty) flame sensor or a “bad grounding of transformer secondary). I am pretty confident I have eliminated the flame sensor as the culprit and I am pretty sure the transformer is properly grounded, but to double check what is the secondary of the transformer?
I have gone over the schematics for the new control board many times over and everything is correct. Could it be possible the new board is bad right out of the box? The new board is not 100% identical to the original but it is a universal that is supposed to work.
Could a dirty burner tube or incorrect gas pressure setting cause this issue? All six burners ignite no problem but something in the boars cuts the voltage to the gas valve after about 6 seconds.
thank you for all of the help
