Replacing Atwood 31501 control board with dinosaur

[foundwaldo]

I am replacing the board off my Atwood 8535-iv-dclp with the dinosaur fan 50 plus pins. Just wondering about the jumper on the dinosaur board. I think I am going to just leave it jumped but not sure. picture is of the old board.

[R.Wold]

Ive had good luck with https://www.dinosaurelectronics.com/ I’d ask them about the jumper. They seem to know this stuff pretty well.

[Fiesta48]

I replaced the original hot water heater control board. Right away you can see the Dinosaur is heavier duty, easy to install, and has a clear cover. Mine is 1.5 years old.

[aether_one]

Originally Posted by R.Wold

Ive had good luck with https://www.dinosaurelectronics.com/ I’d ask them about the jumper. They seem to know this stuff pretty well.

Or just go to their website:

https://www.dinosaurelectronics.com/Fan50_Jumpers.htm

[Old-Biscuit]

Follow the 'Installation Instructions' that came with the Dino Board

[foundwaldo]

Well I am out of ideas I replaced the board and still have the same thing happening.

It lights runs for like 5 seconds then shuts gas off. Does this 3 times then locks out. does anyone know if there is a thermalcoupler on my unit and where it would be. I have looked and can not seem to find it. Atwood 8535-iv-dclp.

[R.Wold]

Yes - short cycling was the necessary clue. It sounds like your high temp limit switch. On mine it was on top of the heat exchanger box, two white wires going to it. You can jump these together to test it. It’s about a $12 part but you’ll have to either pull the whole furnace to get to it or the stove/oven or whatever is on top of it. I by-passed mine temporarily but wouldn’t recommend it to anyone else as a permanent fix.

https://www.irv2.com/forums/f54/atwo...ng-319077.html

Lots of good info here but skip straight to post #7 - Old-Biscuit also explains other causes of short cycling..

It looks Something like this:

[Waiter21]

Sounds like flame sensor isn't detecting the flame.

[jmerritt]

Before you throw any more money on parts to fix your water heater, disconnect and clean all electrical connections and grounds. Apply dielectric compound on them to prevent corrosion. Also, check the alignment of the burner tube to the gas valve to make sure it is straight. I found most of the problems with water heaters is corrosion of the connections.

[Old-Biscuit]

Originally Posted by Waiter21

Sounds like flame sensor isn't detecting the flame.

Exactly..........


Spark electrode not only provides the High Voltage spark for ignition BUT is also used as flame sensor to PROVE flame lit.
All that takes place with in few seconds of trail for ignition (gas valve opening, spark occuring, flame lighting and PROVING it lit)
No flame signal---circuit board shutsdown DC to gas valve to prevent accumulation of raw fuel.


Spark electrode:
*Clean soot.carbon off using emery cloth
*Connector to transformer at board needs to be clean/tight
*High voltage wire to ceramic should NOT be loose
*Ceramic should NOT have any cracks
*Spark electrode must e englufed in flame and have correct gap

*Mounting screw for electrode assembly MUST have clean/tight connection (ground)


Lighting off for 5 seconds does NOT provide enough heat to trip High Temp Limit Switch.
Flaming Proving is the issue....spark electrode

[Old-Biscuit]

Originally Posted by jmerritt

Before you throw any more money on parts to fix your water heater, disconnect and clean all electrical connections and grounds. Apply dielectric compound on them to prevent corrosion. Also, check the alignment of the burner tube to the gas valve to make sure it is straight. I found most of the problems with water heaters is corrosion of the connections.

OP is having issues with FURNACE
Cleaning connections is always a good idea..

[foundwaldo]

Originally Posted by Waiter21

Sounds like flame sensor isn't detecting the flame.

I think so to, but I can not figure out where it is. I thought it was built into the electrode. But I replaced that.

[WagonMaster]

The flame sensor is.....the flame. Believe it or not a flame will conduct a small amount of current. Control boards are designed to sense the current flow through a flame.

[Old-Biscuit]

Originally Posted by WagonMaster

The flame sensor is.....the flame. Believe it or not a flame will conduct a small amount of current. Control boards are designed to sense the current flow through a flame.

Via the Spark Electrode.
Flame generates an AC current which is retified into a DC current which is sensed by circuit board (change in current) via the spark electrode.