Water heater works on electric but not with propane

[Aina808]

I have a Suburban WD6 water heater that works on electric or propane.
Propane doesn’t work, when I turn it on it does click click click, 3 times as the manual says then stops.
I dared to put a match by the tube and a big flame shooter out for 3 seconds then stopped.
I gave up for a while since it works on electric (but I have to run the generator since I don’t have - yet - my solar powered electricity installed :-(
Following my brother’s advice to try again with a long nose lighter so we can trouble shoot and order some parts, I first tried to turn off the little switch (need to be on for electric) in the bottom left corner of the water heater. It is IMPOSSIBLE to move that switch and it is stuck on the ON position…
Any idea? I’ll take some pictures tomorrow.

[jsb5717]

When ours did the same thing it turned out to be the main control board. It's an easy replacement if you can get to it.

[chuckster57]

The switch only controls the 120V to the element.

You need to check the tube for any obstructions, it may require removing it first. If you’re hearing a clicking noise, the most likely issue is gas related.

[LHaven]

Originally Posted by jsb5717

When ours did the same thing it turned out to be the main control board. It's an easy replacement if you can get to it.

If the igniter is clicking, and the gas valve is opening (OP says he coaxed a big flame out of it) the problem is more likely to be physical (clogged or leaky tubing, etc.) than electronic.

[NH_Bulldog]

I have a Dometic/Atwood and had the same issue a few years ago. I even tried the things you did (I still have eyebrows and arm hair), and received a short ignition of gas with a long lighter. It was not a blockage since it worked fine up until it stopped working. The fix was a new control board. It was at the height of Covid so I sent pictures and they sent me a new board. It took some time due to supply chain issues so in the interim, I picked up a Dinosaur brand control board while I waited. The replacement came and it’s been in my toolbox since. Might be worth seeing if Dinosaur has a board for yours. This is a picture of the back of my control board where something obviously failed.

[jsb5717]

Originally Posted by LHaven

If the igniter is clicking, and the gas valve is opening (OP says he coaxed a big flame out of it) the problem is more likely to be physical (clogged or leaky tubing, etc.) than electronic.

Good point. I guess I didn't read the symptoms closely enough. But still could be a board issue if the controller isn't opening the propane valve. Failure to ignite can be a bugger to diagnose. You should be able to hear the propane valve attempting to open, or smell propane if it is opening but not igniting. If there's no attempt to open the valve then still maybe the main board. If it is opening but won't light then it could be a valve problem.

It's a pain but if you can get access to the main board with a multi meter and start tracing electrical signal through the ignition steps it can lead you to the answer.