Attwood furnace will not contnue heating
Hello All: The rear furnace on my 2003 39' Discovery will not stay on. It tries three times then go into lockout. Each try the burner fires but does not continue. The front furnace works fine. I d...
Forum Discussion
The sequence (Shortened to match your problem)
First: Attwood makes two different designs, One has a combination Thermocouple (Flame Sensor) Ignighter (Point) (the other point is ground) this carries about 1,000 volts during ignition and just under a half volt as flame sense on the same wire.. Imagine a switch failing and putting 1KV on the device deisgned to sens 1/2 volt and you have what I think happened to my control board.
Possible issues:
Bad burner adjustment, not getting hot enough (not likely but possible)
Obstructed flame/exhaust path (More likely)
Bad/dirty thermocouple Try cleaning it first.
Bad connection on one end or the other of the wire. (This would not bother the thousand volts but would the half volt) Disconnect and reconnect a few times.
Bad control board (DING DING DING) this is what happened to my furnace, a new board costs about 250 bucks (or rather did then) plus S&H, a new board from Dinosaur Boards, S&H included was less than 110 bucks (2 dollars less)
I opened the box.. I am a trained electronics technician, I was seriously impressed with the construction and workmanship, Way better than the OEM in my not very humble opinion, Several others have said the same thing. I have done a bit of electronics design and construction so I gave the board another look,, Sitting there on the component side is a neat little device, Might have cost as much as five cents in bulk but I doubt it.. I happen to know what it's for... It is to protect the flame sensor chip from the kilovolt (It clamps the voltage to 90, or possibly less depending what gas is in the tube). Appears Dino boards agrees with my theory of what went wrong.
Board fit, i did add a couple of zip ties to hold it in place since another of the improvements meant it might fall off the mounting bracket.
Recommendation: Rule out everything else before you spring for a new Dino board.
First: Attwood makes two different designs, One has a combination Thermocouple (Flame Sensor) Ignighter (Point) (the other point is ground) this carries about 1,000 volts during ignition and just under a half volt as flame sense on the same wire.. Imagine a switch failing and putting 1KV on the device deisgned to sens 1/2 volt and you have what I think happened to my control board.
Possible issues:
Bad burner adjustment, not getting hot enough (not likely but possible)
Obstructed flame/exhaust path (More likely)
Bad/dirty thermocouple Try cleaning it first.
Bad connection on one end or the other of the wire. (This would not bother the thousand volts but would the half volt) Disconnect and reconnect a few times.
Bad control board (DING DING DING) this is what happened to my furnace, a new board costs about 250 bucks (or rather did then) plus S&H, a new board from Dinosaur Boards, S&H included was less than 110 bucks (2 dollars less)
I opened the box.. I am a trained electronics technician, I was seriously impressed with the construction and workmanship, Way better than the OEM in my not very humble opinion, Several others have said the same thing. I have done a bit of electronics design and construction so I gave the board another look,, Sitting there on the component side is a neat little device, Might have cost as much as five cents in bulk but I doubt it.. I happen to know what it's for... It is to protect the flame sensor chip from the kilovolt (It clamps the voltage to 90, or possibly less depending what gas is in the tube). Appears Dino boards agrees with my theory of what went wrong.
Board fit, i did add a couple of zip ties to hold it in place since another of the improvements meant it might fall off the mounting bracket.
Recommendation: Rule out everything else before you spring for a new Dino board.
