Hot water heater fault light?

[BuckandTeresa]

I have a 2019 MHC 3330rl. My dual electric/gas hot water heater SW12DEL works with the electric switch, but when I hit the GAS switch inside on the main control panel, I get a red FAULT light on the panel in the top center. I have read the owner’s manual, no help. I tried the five-second-off, back on, five-second-on technique mentioned in the owner’s manual. No luck. Went outside, pushed both reset buttons, which were still in, and nothing. Turned the main power switch outside on and off. Went back inside, still got the fault light when I pushed the gas switch ON.

Anybody have any help?

[rohrmann]

That light will light every time the gas side goes through an ignition sequence. Once the burner flame is lit, the light will go out. You will see DSI (Direct Spark Ignition) along with FLT next to that light. There is no fault unless the system goes through three cycles attempting to light the burner, and if there just wasn't gas in the line to the water heater, just turn it off and then back on and it will go through that lighting sequence again. Also, it is a water heater, not a HOT water heater.

[Carl n Susan]

Obviously, the burner is not lighting. There are a number of possible reasons: bad gas solenoid, bad gas valve, obstruction in the burner tube, or ? Stand outside when someone turns on the gas operation. Do you hear the solenoid click, did the igniter spark, and/or did the burner light and then shut off?

Here is a link to the Suburban SW12DE 12V DC Troubleshooting manual which should help you find the problem.
https://www.montanaowners.com/forums...?do=file&id=90

[BuckandTeresa]

Carl, Thanks so much for the link!

[BuckandTeresa]

Thanks for the quick answer.

No, my panel doesn’t have DSI next to it, only FAULT. Thanks for playing.

[BuckandTeresa]

Thanks, guys (I am assuming here…)!

I waited an hour and tried it again. No fault light!

I am thinking since I almost never turn on the gas switch, perhaps there was air in the gas line that slowly purged out as new gas was let in.

I really depend on the good advice I get in this forum. I’ve fixed a bunch of things with the info from you all. I read every newsletter posting as soon as I see it. I figure if I don’t have that particular problem yet, my POS MHC will give it to me soon enough.

Thanks again!

[Daryles]

Long time ago, I had that issue. Worked on electric not on gas. I read somewhere in the manual, the gas won't kick on until the water temp is below 110⁰F.
I ran the hot water until it was cold then turned on the gas mode. It worked as advertised.

[BuckandTeresa]

Interesting! Thanks!

[BuckandTeresa]

Carl,
Just read the linked manual you sent me. Very clear and easy to see and understand each point. Thanks!

[Kfinnert]

Good morning -

I had the same issue with mine. There was air in the line and the red-light would come on as the ignition went through the sequence. After three tries, it will remain lit if there is no ignition. It made sense since air in the line would not allow sufficient gas to reach the ignitor to start the heater.

My fix, when going onto gas, I will bleed the lines of air starting at my stove top. Bleed the line of air? Yes!

What I do is insure all of the gas services downstream from the water heater - mine is the stove, are lighting and then I start the water heater. Thru the lighting sequence with stove top and oven first, I am able to get the air out of the lines and, as such, I have not had the issue with the water heater not igniting.

My rig is a 2008 Montana 5th wheel!

Cheers

[BuckandTeresa]

Kfinnert,
Thanks so much! This sounds like a good solution!

Buck

[BuckandTeresa]

In fact, now that you bring it up, I used my external gas port to run a gas fire pit one night, and the next time I tried the gas HOT water heater (that was just for you, Rohrmann), it lit right off. I guess I purged the air into the fire pit during startup. Thanks again!