Atwood Water Heater Won't Operate on Gas

Thank you, will update.

The manual that phays posted tells you how to trouble shoot the board and the other components of the systems. If the board is green you can see all the components and look at the backside for any burned tracks on the board and the front to see any components that look burned or melted. The potted board you will have to check with your ohm meter. I would check and clean all the connects first especially the grounds and igniter to see if that helps.

Download this manual

Atwood service manual

I just had to replace electronic board on Atwood furnace.
About $90 for Dinosour on Amazon.
New board are convertible, so you can use it on WH. refrigerator or furnace with fan delay.

I've had to replace the board on a couple units, but I've fixed a lot more just by cleaning all the connections to the board. If its aged, and all elsse fails, CLEAN those connections !!

Being an 8E means it has separate controls for electric and propane systems
AC side has it's own set of t-stats and on/off switch located on backside of WH Tank.
You stated that it works---heats water

Propane System uses DC power.

First thing to check if not working is the 'thermal cut out' fuse.
Goes from control module to t-stat (brown wire)---it is a one time fuse blows at 190*F. If blown.....no DC to operate propane side.

You can remove it (for testing) and hook brown wire directly to t-stat.
Turn water heater propane on and check for spark and main flame.

If the thermal fuse blew it is do to a dirty/obstructed combustion chamber (flame blow back outside of combustion chamber so clean it)

If bypassing thermal doesn't work then you need to test for 12V DC power and where you are loosing it.

I had to replace the control board for my Norcold refrigerator because while it worked fine on 120v, it would go into a safety lockout when it switched to propane. It would spark and the flame ignite but the control board never sensed the flame was there and continued sparking until it locked out. Sounds like the same problem. I bought a replacement from Dinosaur Electronics because they offer a 3 year warranty.

Dinosaur's replacement board for Atwood water heaters

Does the light come on when you turn switch on?
If yes, then power is getting to the circuit board.
Have a helper turn on the water heater switch while you listen for spark clicking at the water heater.
No clicking, could be bad board or the ignitor is out of adjustment.
Yes clicking could mean that the gas valve is not operating. Check for continuity on the two coils of the gas valve. Disconnect them so you get good readings. Coils should have same resistance. Check the ground on the coils. It is in bad place behind gas valve. make sure it is clean and tight.
Have helper turn on water heater switch, while you check for voltage at the gas valve.
Check the ECO and thermostat for continuity. They should have good continuity when the water heater is cool and not heated by 120 volt element.

Atwood manual

It DOES have that little light, huh? The youtube I saw had a different circuit board I wasn't sure if mine had the light.

It's a G6A-8E

You need to locate the exact model number. It is located on the frame of the water heater access.
First it requires 12 volts DC for the Direct Spark Ignition.(DSI)
Does the small light next to the water heater switch light up? If no there is a good chance you have no 12 volts to the switch or the switch is bad. The light should come on if power is reaching the circuit board.