Suburban SW6DE water heater won't stay lit

[Theotilus]

I have a 2003 fifth wheel with a Suburban SW6DE water heater. The propane side was working fine until the fifth wheel sat unused for a few months. The electric side works.
It has a direct ignition system. When I try to light the water heater the flame ignites and then it shuts off. It goes through this cycle 3 times and then locks out. What is the most likely problem. I cleaned the electrode. The gas burner is clean with no obstructions.
I have checked the reset buttons - all good.

Thanks for any help or ideas,
Ted

[Durb]

I had the same water heater except 2004. It worked fine until I took the wife and two granddaughters on a trip. Same symptoms, no hot water, not good. Fortunately Camping world was close by and I replaced the circuit board and igniter in the campground - easy but expensive. The WH worked perfectly for 3 years after when I sold the trailer. It was probably one or the other but I wasn't going to jeopardize an anticipated trip guessing. I checked the pricing on the internet later - paid way too much. The price of local inventory and convenience - was glad to pay it. Had a wonderful time.

[Fisher_Bill]

I think I fixed mine with a new thermo coupler?

Whatever the unit is that confirms the pilot is lit and then continues to deliver the gas, if it's not working then the sensor shuts down the gas with the logic that it's not lit.

There's a test I found online with a volt meter but I just ordered one and got lucky, worked fine after that.

Bill

[Old-Biscuit]

Flame proving....
When main flame lights off a miliamp signal is generated (flame rectification)

This signal MUST reach the circuit board to 'prove' it lit or circuit board drops the DC to gas valve shutting down firing.

Spark electrode is how signal returns,
IT must be engulfed in main flame
Gap s/b 1/8" - 3/16"
Ceramic can not be cracked--signal tracks to ground (wipe it down with a rag sprayed with silicone)
High tension wire connection must be clean/tight...doesn't take much resistance to stop miliamp signal
No carbon/soot on electrode---clean up with emery cloth
Good grounds...


It's all abut the spark electrode.........miliamp proving signal

[jerem0621]

I fought this and fought the same issue.

Turned out the reason the propane wouldn't light is because the electric element was keeping the water hot at home while on shore power. As soon as it would light it would cut off...reason being...it was working as designed.

Do you happen to leave the electric element on at home or where ever you store your trailer?

If so, the water is warm and the thermostat will not let it the propane burner light.

Thanks!

Jeremiah