Quadrafire Classic Bay 1200 convection fan help.

[Butnsie92]

Hello everyone,
I’m new here but I did search for any topics relating to mine but I didn’t see any that could help me. I’m hoping maybe someone here knows something I don’t. I am a HVAC technician but I’m pretty stumped. I have the stove listed above and I had the convection fan fail to come on. I pulled up the wiring diagram and I traced the circuit. My immediate diagnosis was the snap disc is bad because it’s a straight shot from the board to the blower. We’ll I replaced the snap disc number 1 and nothing changed. Then I tried jumping it out. I did and the convection fan works flawlessly. The entire unit works flawlessly. I contacted quadrafire and they suggested I replace the control box. We’ll I did that and nothing changed. I ran a diagnosis with the control box and everything worked flawlessly. I set the box for my stove. I un-jumped everything and placed it all back into operation. I measured the voltage going across the snap disc number 1 and I have 118 volts so the snap disc is okay so why won’t my convection fan run? Does anyone have any ideas of what could be wrong? Is there something I’m missing?

 

[johneh]

replaced the snap disc number 1 and nothing changed. Then I tried jumping it out. I did and the convection fan works flawlessly.

I would say that if you jumped the disc and the fan works that you have a bad disc
another possibility is ash build-up where the disc mounts. Ash makes a great insulator

 

[Butnsie92]

I would say that if you jumped the disc and the fan works that you have a bad disc
another possibility is ash build-up where the disc mounts. Ash makes a great insulator

I thought so to, but I took a voltage reading across the disc and I have 118 volts so the disc is apparently working correctly.

 

[Mt Bob]

If you took a voltage reading"across" the switch and got 118v, then the switch is "open" not closed, as it is reading power and ground. If the switch was closed, you would not have that reading.

 

[johneh]

As you said it works with the wires jumped and does not work with the disc.
The disc is NFG or maybe a bad connector at the disc