Suburban water heater will not keep heating

[Voyager_Mike]

I have a Suburban ten gallon water heater which is just over one year old. (It was a replacement). Suddenly, it quit working. I have replaced the gas valve unit, the high temp thermostat unit, and the control board. As far as I can tell, there is nothing else to replace but the whole heater itself.

What is happening is that when the switch is turned on, it shoots gas into the heater chamber, the spark goes active and I have a hot fire. But when the spark times out, so does the gas.

Any suggestions?

[Voyager_Mike]

OK guys. Consider me properly scolded.

In my defense, the very first thing I looked for was a thermocouple. I have fixed gas water heaters for for friends and family for over fifty years, and every thermocouple I have ever seen had a wire heading out to it. I confess I have always been baffled by two way current. For a similar sixty years, I have never been able to understand how an automobile could be negative ground at a nominal twelve volts (which in these days is actually around fourteen volts) and have a coil with a positive ground at 24 to 48 thousand volts going in the opposite direction through the same car frame.

The thermocouple thing was precisely what I was looking for in the first place, but quickly crossed off due to the only wire that led out of the burn chamber was the spark wire.

A bit of burnishing and the problem was solved. Thank you.

Had I checked with you first, we could have saved nearly three weeks of heating wash water on the stove.

And as for the 2 year warranty, there is a back story to that. When the original water heater went out, I ordered a new one from Amazon for a great price. It was gas/electric. When it came, there was damage to the box and while the box was clearly marked gas/electric, the water heater was gas only. I complained to Amazon and they sent me another water heater in another damaged box. Same markings, same gas only. My presumption was that some clever souls were buying two water heaters and switching the boxes and sending the gas only back in the gas/electric boxes. I tried to work it out with Amazon, but their customer service could not get it. The price was still good for me, even without the electric function which we had hardly used in the first place. I kept one and sent the other back. Under those circumstances, not knowing what was going on with the original heaters, I knowingly elected to eat the guarantee and fix the thing myself.

Anyway, again, thank you.

[dougrainer]

1. I hope you did not buy the parts. Suburban has a 2 year warranty
2. If you DID buy the parts, this is a perfect example of ignorance in repair---Throwing parts at a problem which is why most Appliance suppliers refuse to deal with NON professional Service Technicians for warranty or after warranty help.
3. If you had a Shop doing this work, I would NOT let them work on my RV again.
4. Your symptoms point to a defective Spark Electrode. (Cheapest part you could replace). The Spark Electrode transmits the spark current and the returns the ac voltage to the board to signal flame. If it has microscopic cracks in the Porcelain, it cannot return the AC voltage signal. Doug

[SCVJeff]

ScottG wrote:
Agree with OB. Your fix is probably as simple as cleaning the flame sensor and then making sure it's in the hot part of the flame so it doesn't soot up again soon.

I've also had to remove and burnish all connected parts from the ground probe all the way to wherever ground for the board lands. Beach camping and corrosion that's almost invisible is enough to shut it off

[old_guy]

also look at connections under the rubber boot, happened to me and all we did was wiggle the wires and it started working again. I cleaned the posts and made the fitting a a little tighter and no problems since then

[ScottG]

Agree with OB. Your fix is probably as simple as cleaning the flame sensor and then making sure it's in the hot part of the flame so it doesn't soot up again soon.

[Old-Biscuit]

Well instead of throwing parts at it.......
Didn't need gas valve, or thermostats or control board


Flame lights off but is not PROVING
Flame has to PROVE it lit or circuit board will drop DC to gas valve solenoid shutting it so raw gas doesn't flow

Flame PROVING is done via 'flame ionization' -----a milivolt signal is generated and sent back to circuit board via spark electrode

Spark electrode:
Has to be clean....emery cloth to remove soot/carbon
Has to be 'engulfed' in main flame....adjust position
Has to have clean/tight connection on high tension wire...plug off and clean/make sure it goes on tight
Has to be free of cracks in ceramic...check for ground tracking at night/in the dark...replace electrode if cracks