Atwood-Dometic Water Heater Igniter Board

[Mikec557]

GD Reflection 5th wheel, Atwood-Dometic 6gal water-heater 120vac/propane, 2018 model but used full time for 1.5 years.
model number GC6AA-10E

The short version is this... I have only 9.2v from the igniter board to the various wire connections that lead to the solenoid, and the solenoid does not "click" open... though some propane gets through when it efforts to ignite.

The sparker doesn't spark, but a flick-a-bic will ignite what little propane gets past the solenoid during the ignition effort. But the propane will shut off after the failed ignition sequence.

The Atwood trouble shooting guide says it needs a minimum of 10.5v to work properly. I measured the voltage from the wire harness going into the igniter board. It was either 12.4 or 13.4, I don't remember which, but it seems to me it was the full battery voltage.

It would seem to me that the igniter board is failing to pass along 10.5-12+v to the thermal fuse, thermostats, and solenoid... but I would have thought it would just outright fail rather than deliver a substandard 9.2v.

Before I spend $120 on a new igniter board, I thought I would ask for your thoughts and ideas.

Thanks in advance
Mike C

[Big Blue]

A weak ground to the circuit board on our old Class-C caused a failure to light...I found a better spot for the ground and kept the heater working for another year... then had to replace the board.... I suggest checking out Dinosaur Electronics if you need a circuit board... well made with a 5 year warranty...

[Bruce1sp]

Atwood is aware of a bad batch of boards. Zhongding is the manufacterer.
They may send you a replacement for free. Will need model # and serial #

[RVing in Michigan]

Suggestion for preventative maintenance; When you wash your rig, soap and water gets through the water heater vent screen and behind the cover. The PC board sits exposed behind the cover. These low cost electrical parts cannot handle this. To protect it, spray your control board with a product designed for them. Such as "Fluid Film". It will not dry up and seals out the chemicals. Do not use solvent based products like WD40. They attack the varnish coating on your board and can even cause an explosion in a confined area when the circuits are energized.

[RickLight]

They replaced mine and paid the shop as well!
Apparently a dealer test of the bad board was required. The shop had the tool and didn't make me wait a week, like the big dealer in the big town. The whole thing took an hour.

Thanks to https://www.extremerv.com/

[Mikec557]

Just a quick follow up in case it may help someone else with similar problems...

I had checked the thermo-fuse, aka thermo-coupler, for continuity and it passed. Given that, I replaced the circuit board with a Dinosaur Electronics control board. I thought as long as I'm having to pay for a new board, I'm fed up with dometic boards, having had the refrigerator board go bad in less than 12 months too. At the same time I ordered that from Amazon I also ordered a two pack of the thermo-couplers and a thermostat replacement kit.

I put the board in and the water heater fired right up. That seemed to solve the problem, but then it turned off. While that start up was better than what I had before, it obviously was not good enough. Because I had it, I replaced the thermo-coupler with one of the new ones. Bingo. Now it works perfectly. But. That doesn't really make sense. Remember, I was getting 9 volts instead of 12 volts. I thought that had to mean the board was defective. How could a thermocoupler, which is an on-off switch, partially work and let 9 of 12 volts pass through? I don't know. What I know is that it works with a new board and a new thermo coupler. I kept the old board for two reasons. First, it works on 120vac for sure. Second, it may not be defective, it may have been something I can't explain in the old thermocoupler. At the time we were full-timing in our RV and having something work is more important than understanding why. So there you have it. It was about $130 for the dino board, and about $15 for two thermo couplers.

[Big Blue]

Mike, Thanks for the update... to many threads are never updated with the fix.... It would seem you had a high resistance in the "Thermal Switch" circut.... The new board had just enough better voltage to open the gas valve.... I jumper both switchs as my 1st step to troubleshoot... living in a high humidity part of the country... any electrical contacts are high on my suspect list.... Thanks again ... Norm

[jkwilson]

A thermocouple isn’t a thermal fuse or an on-off switch. It produces a small voltage based on the temperature of the probe. The board measures the voltage and takes the appropriate action.

[Buckaroo]

Just a quick follow up in case it may help someone else with similar problems...

I had checked the thermo-fuse, aka thermo-coupler, for continuity and it passed. Given that, I replaced the circuit board with a Dinosaur Electronics control board. I thought as long as I'm having to pay for a new board, I'm fed up with dometic boards, having had the refrigerator board go bad in less than 12 months too. At the same time I ordered that from Amazon I also ordered a two pack of the thermo-couplers and a thermostat replacement kit.

I put the board in and the water heater fired right up. That seemed to solve the problem, but then it turned off. While that start up was better than what I had before, it obviously was not good enough. Because I had it, I replaced the thermo-coupler with one of the new ones. Bingo. Now it works perfectly. But. That doesn't really make sense. Remember, I was getting 9 volts instead of 12 volts. I thought that had to mean the board was defective. How could a thermocoupler, which is an on-off switch, partially work and let 9 of 12 volts pass through? I don't know. What I know is that it works with a new board and a new thermo coupler. I kept the old board for two reasons. First, it works on 120vac for sure. Second, it may not be defective, it may have been something I can't explain in the old thermocoupler. At the time we were full-timing in our RV and having something work is more important than understanding why. So there you have it. It was about $130 for the dino board, and about $15 for two thermo couplers.

Mike - I think you are talking about the thermal fuse, not a thermocouple - two different things as @jkwilson indicated. You are correct that the thermal fuse is on (if good) and off (if blown). It sounds, however, like you had corrosion on the spade terminals where it connects to the unit. The corrosion will increase resistance and reduce voltage flow. I just had this happen on my unit - would not fire up on gas or electric and it fired up immediately as I started to remove the spade terminal connection. The Service Manual indicates that corrosion on the wire connections is the most frequent cause of intermittent starting issues. Not surprising given that water from the pressure relief valve drips on them.

[Big Blue]

A thermocouple isn’t a thermal fuse or an on-off switch. It produces a small voltage based on the temperature of the probe. The board measures the voltage and takes the appropriate action.

Correct... A thermocouple is a probe with 2 dissimialar metals that when heated create a small voltage.. the hotter it gets the more volts.. That voltage can then be calibrated to be read on a gauge.. ( like the one that reads exhaust temp on my old Dodge Truck or a PW4000 jet engine.) A Thermal Fuse depending on the design may or may not reset... The 2 thermal switchs wired in series have seperate functions.. one opens at the desired hot water temp.. the other acts as a Fuse to prevent extreme over temps...