Furnace Trouble

[Boss]

I posted once before but still having a problem; now I have started to work on it and it’s inconclusive. Originally what happened was the furnace quit running when turned on the fan would run for 15-20s then quit. I removed the furnace to get access to the control board and sail switch. I tested continuity on the sail switch worked fine. Removed the switch and manually closed it then turned on the furnace. The flame would ignite then quit and repeat without staying on continuously. I then reinstalled the sail switch and it worked the same way it would ignite but not stay lite continuously. Would the furnace act this way because it’s not vented properly as it’s not in it’s installed state or is it a board issue?

[Northofu1]

https://www.youtube.com/watch?v=884pjgcHnc4

Try this before replacing

[Northofu1]

or this

https://www.youtube.com/watch?v=N-zqTLjG7qA

[jefisch]

I had a similar situation where the blower would start up and run for about 25 seconds then turn off. Never any flame.

At first it would only occur occasionally, but as time went on it would happen more frequently until it failed every time. That was the morning of the big snowstorm. ��

The furnace was still under warranty so I took it to certified repair facility. They confirmed the problem, removed the furnace, and began diagnostic testing... and found nothing wrong. It worked fine on the bench. Reinstalled in the coach and it failed.

They went back and forth multiple times until they accidentally discovered that the intake grill was too close to the wall. They pulled it back about 1/2 inch and it seems to work fine.

It’s still kind of a mystery because it worked for a year in the original factory mounting position before it started incrementally failing. It’s not like it was moving closer to the wall on its own.