water heater

[RobertS]

Need some help to get hot water heater working for winter. I have Atwood G6A-6E propane water heater with electric start. There is no light on the circuit board.
I have:
tested the temp switches, and the are closed
12 volts coming from full time red switch in coach
good ground to all connections
electric arc, spark at igniter when first turned on
the propane red connectors show 80 ohms to ground
the propane switch clicks loudly when 12 volts connected with separate battery
when propane switch connected to separate battery no gas flow
all other propane gas fixtures operate
no voltage on red wire from control box
all contacts cleaned

need ideas and help

SS

[skater]

Is the venturi tub clear? Spiders like propane...

[RobertS]

Thank you for reply

Yes cleaned tube and gas jet. two items that puzzle me:

When I hook 12 vt dc to valve, relay clicks but no propane smell nor any flame when holding flame to nozzle

I have 12 volt dc on both brown wires, from coach switch and passing through thermostatic switch on tank, but no voltage on red wires

SS

[skater]

Thank you for reply

Yes cleaned tube and gas jet. two items that puzzle me:

When I hook 12 vt dc to valve, relay clicks but no propane smell nor any flame when holding flame to nozzle

I have 12 volt dc on both brown wires, from coach switch and passing through thermostatic switch on tank, but no voltage on red wires

SS

Not that I advocate doing dangerous things with propane, but have you disconnected the line and confirmed you have gas flow at the water heater?

[RobertS]

Thank you for reply

No , good idea to check for propane, I will get some soapy water and test in morning

SS

[RobertS]

tested supply line and propane flows to relay switch. applied 12vt to relay switch, no bubbles of propane coming out of cleaned brass jet. Should I disassemble the relay switch of just replace. As my father would say " can not make worse, it is already broken"
Need to get brass stop to plug the propane line to continue MH use while working on fix

SS

[skater]

Just so I understand the situation: You turn the switch on. The light on the switch turns on. The ignitor triggers, but the burner never lights, right? Do you hear the gas valve activating?

[RobertS]

You understand correctly. The light red switch in coach stays on and the igniter sparks for 3 seconds with no flame produced. If the coach switch is left on after about 3 minutes it will spark igniter again no flame.
I do not hear any propane nor does holding a hand held igniter at brass jet show any propane.
As an extra test of the propane solenoid switch, I have tested with ohm meter (.8 reading) and connected 12 volt battery. When connecting the 12 vt battery the solenoid switch clicks but no propane flows from brass jet

Again thank you for your interest and comments

SS

[skater]

Well, it pretty much has to be the solenoid valve then, right?

[silvertrooper]

I know this is an old thread, but maybe this will help others. I had the same issue. My repair shop diagnosed the problem as a burned-out control board. Based on youtube videos this is a very common problem (appears right away in search). If you have the correct part (if you know your water heater model this should be straightforward to determine--I saw a US-made replacement company named Dinosaur in the vid I watched) the repair looks easy. Of course, the video is on a modern RV, with easy access to the water heater. With our old units, I didn't know if they are plug-in wires or need some other connection. I know that the water heater seems like it might be a bitch to access, if you have to go from the back-but lo and behold this repair is done from the side panel. In about five minutes.

I didn't have the work done at the shop (estimate $700) because, 700 dollars. Instead, I saved about $600 plus major hassle by doing it myself.

The board is the Dinosaur UIB64:http://www.dinosaurelectronics.com/UIB-64.html which I got through Amazon for about $125. It is a universal control board and should fit the water heater in all Bs.

Installed it and the water heater fired right up and has worked every time since.

[cheezwhiz]

I’ve been a lurker since 2021 and have benefited immensely from many posts. We have a 1992, bought on ebay in 2018. 56 miles into our drive back to RI, the beast over-heated. By some miracle, we were a few hundred feet from an exit and got off and drove directly into an RV storage and repair facility. We learned the seller had put Bar’s leak stop in the radiator. Many lessons learned and repairs/upgrades made since then. Skip forward to now - the hot water heater stopped working.

After many hours searching through this site, asking AI, looking at the Dometic site, I found “RV repairwoman” on YouTube. She has very several thorough walk throughs of Atwood/Dometic water heater diagnosis, and much more valuable information.

Long story shorter, I finally found a nearly exact replacement for the gas only control board part 91367 on Amazon for $30, https://a.co/d/03pGFikA. The 6 pin electrical connectors are on the top instead of on the side, so start with the brown wire on the left and it’s plug and play. While I was at it I replaced the igniter, ECO and T’STAT and the thermal connector- because $8 and 14. I had replaced the gas valve a year ago - easy diagnosis because the outside of the van reeked of propane and the valve was stuck open.

A word of caution: the first control board (different model) arrived defective. I ordered 2 of the ultimately successful boards. The first was DOA. The second works well. Buy 2 and hope for the best.