Burner Won't Light After Fan Control Module Replaced

[ccstevens4417]

This should be a quick fix...famous last words I guess.

Heatilator - NDV3630I

Everything was working fine, my fan control module was just stuck at the lowest speed so I ordered a replacement.

After replacing the fan controller, the burner won't light. (blower works great now) Pilot comes on when I flip the wall switch but no burner start. It's like the burner valve suddenly stopped opening.

It must have been something I did, but I can't figure it out for the life of me. This is what I've done so far:

1) I put the old fan controller back in - no fix, same issue
2) Pulled the wiring harness off and olhm'ed out all the wires - all good
3) Looked up the olhm values for the pilot and burner valves (I think I found the right values on the net) - both good
4) I thought, maybe I damaged the main Dexen controller somehow, so I ordered a replacement - same issue

Is there something I can jump to test? It looks like that wire coming off the controller to the burner valve is negative. Does it get a ground?

What am I missing? It was working no problem. My wife is starting to doubt my abilities. Any thoughts would be appreciated!

Charlie

 

[DAKSY]

Have you tried rapping on the valve with the handle of a plastic screwdriver? Sounds like a solenoid issue. Rapping might free it up.

 

[ccstevens4417]

Yes, thanks Bob, tried that too.

 

[DAKSY]

Is the ground wire tight? Should be a zipscrew holding it the unit’s body. Generally through the floor of the unit. Even if it IS tight the contact can become corroded. Try moving it to another location…

 

[ccstevens4417]

I'll take a look, but I would think if it was the main ground I'd have issue with the pilot lighting also and it lights just fine. Like I said this thing was working perfectly until I swapped out the bad fan control module.

I agree with your earlier post, seems like the burner valve is not opening. I found some olhm values online but unsure if they are correct for my unit. What I found said pilot side should read 60 olhms and the burner side 40 olhms. That's what I get for both, so if those values are correct, I'm assuming the solenoid is good? That made me think the valve was just stuck, but I've rapped pretty hard at this point with no luck.

Just too much of a coincidence for me that this just started at that module replacement.