Tricky question about Atwood Water Heater

[dvitale300]

OK - who we’re currently camping at an RV lot. Have a 6 gal propane only Atwood water heater. Serviced and Thermocupler replaced last fall.

The only way I can get the water heater to stay on is to use my onboard fresh water with the water pump, and turn one of the inside faucets to a trickle.

Any other way - no trickle, on city water with trickle, the water heater clicks, goes on, shuts off after 5 seconds, repeats this cycle 2 more times and doesn’t work.

Can anyone tell me what’s going on? - thanks

[daveengstrand]

I've had a problem with the thermostat a couple times. It just sits against the tank and got dirty between it and the tank. Took it out,cleaned it and put it back and worked just fine. simple to check.

[Old-Biscuit]

dvitale300 wrote:
2015 Starcraft Ultralight. I know - it’s weird but replicatable. Got out of the shower - fine. Turned the trickle off - heater went off. Turned city water on - doesn’t work.

Then you do not have a thermocouple.......just the spark electrode which provides the high voltage spark for ignition AND the return path for the 'flame proof' signal.

When main flame lights off a milliamp signal is generated via flame rectification
This signal proves main flame has lit and circuit board can hold DC on gas valve.
W/O that signal getting back the circuit board drops DC off of the gas valve solenoids shutting down propane flow so raw fuel doesn't accumulate


3 attempts then circuit board 'faults' and 'locks out'


Clean up, reposition, replace spark electrode
Clean up and tighten ground connections of water heater
Green wires and the spark electrode assembly mount screw


Thermal Fuse (clear tube---brown wire to t-stat), t-stat and ECO (Energy Cut Off---Hi temp T-stat) are not the issues
If Thermal Fuse was bad............NO DC/No heat functions period
If t-stat..no heating OR if loose then temps would go HIGH
If ECO....no heating OR if loose then temps would go REAL high and T&P Relief Valve would be dripping/ready to pop open


Spark Electrode........

[Jim]

Those are strange symptoms...but the 3 strikes thing reminds me of a problem I had with my old '94's water heater. That turned out to be a bad spark igniter circuit. Once replaced, that particular issue was gone. Your heater though, sounds like you've got 2-3 things going on. So I'd recommend checking your main ground for the heater. Also check all the electrical connections under the lid, be sure they're clean. Both ends where necessary.

Note that the thermal disks and chemical fuse can all be shorted out to test them so make yourself a shorting wire.

Here's some pictures when I worked on mine: Water Heater Repairs

[diazr2]

Have you tried draining the hot water tank then fill it up again?? Maybe your tank is waterlogged. Very strange please let us know what you fine out.

[dvitale300]

2015 Starcraft Ultralight. I know - it’s weird but replicatable. Got out of the shower - fine. Turned the trickle off - heater went off. Turned city water on - doesn’t work.

[Old-Biscuit]

Dirty/sooted up 'spark electrode'.....used to return flame proven signal
Dirty/corroded/loose 'spark electrode' high tension wire connection on circuit board----used to return flame proven signal

'Spark electrode' not directly in flame ---must be engulfed in flame so return flame proven signal can be generated

Is' all about getting the flame proven signal returned to circuit board so DC remains on gas valve solenoids-----until water temp is reached and t-stat shuts down heating cycle

Nothing to do with/with out 'trickle' of water

What YEAR is your trailer??????

[GordonThree]

Flame sensor maybe. It's different than the thermocouple.