Any furnace guru's?

[Moms68]

Well - my next move is still taking out the bracketing to get to the dang flame sensor - but - the furnace still plugs away giving some heat sometimes nicely and then not so much...but some heat...and but it's been friggin cold enough here not wanting to do this if I encounter a hassle that will have me with no heat for a day or longer. Right now far as I can tell, a root cause of the trip outs aim to the sensor. Hope this is what it is. My go-to furnace outfit I've used won't service Lennox so have it on the list to find a place that does. Appreciate you asking and will update hopefully with a success story.

Very odd that the problem is intermittent, would tend to eliminate a flame sensor issue. Maybe a loose connection or a gas pressure problem.

 

[hunt2elk]

Very odd that the problem is intermittent, would tend to eliminate a flame sensor issue. Maybe a loose connection or a gas pressure problem.

Yeah, I would bet money it isn't the flame sensor. Had 1 a few weeks ago acting like this one. It would go for a few days and then lockout. Would always restart after resetting the board and would run fine for 1-3 days. Finally by accident found that the wire connectors inside the valve were not always making contact. It would be running fine until you gently touched the wire connector on the valve. Replaced the valve and it's been fine ever since. I've had similar issues with printed circuit boards.

 

[Ron H]

No doubt you gents know more than I do; I had read that a root problem with it acting this way was the flame sensor listed as the the next thing to look at on a couple of sites (I put in new rollout and hi-limit switches, new blower/motor). The sensor has never been out having this unit 20 years. When I gently tap on the unit with the back of my screwdriver handle near the hi-limit switch it works fine for a while.
I will try touching the wire though next - could be my tapping trick is jiggling that wire just enough. Pressure checks or a new valve is something I'll let a tech do if the sensor doesn't do it....thanks!

 

[RemCharger]

I always inspect the back side of the mother board for solder cracks on these type of intermittent problems. Magnifying glass if bad sight lol. Resolder,, done.