No DSI light, no flame

[zox]

I've been living in a 2017 Heartland Bighorn for 6 months. It has a SW12DE Suburban WH
that has worked fine using both 120v and LP. Last week I flipped the LP switch
and the DSI light did not come on. It always comes on for several seconds. This time
no light, no fire, no hot water. 120v does work.
This first thing I checked was the LP thermostats. .1 ohms across the thermostats. Good.
Then I turned on the LP switch and checked voltage at the wire that comes from the LP
switch, at the thermostat. 0 volts. No good.
Next I replaced the 520814mc control module, knowing that probably wouldn't fix the problem.
It didn't. Next I checked the switch in the control panel inside. It checked good.
Then I ran a new wire from the control panel, through the basement, to the thermostat.
That was fun. Flipped the switch, no DSI light, no fire. So I checked the voltage at the
new wire at the thermostat and got 13.1 volts. That's good.
The furnace and stove work fine.
I forgot to mention, I checked the continuity between the thermostat and control module.
Good. I'm stumped. Any ideas?

 

[Bogie]

The Suburban trouble shooting guide in the tools section of this forum may help you to diagnose
the problem.

You can find it here: https://manuals.heartlandowners.org/manuals/Troubleshooting Guides and Tips/Water Heater Troubleshooting - Suburban V1.3.pdf

 

[wdk450]

The most common thing that I have noted reported on the forum about the Suburban water heaters in Heartlands is that the supply wiring from the trailer is stretched tight to the connection box on the outside of the water heater inside the access compartment, secured with just wirenuts, and sometimes this connection comes apart. I think that usually this is the 120 volt supply, but 12 volts DC comes into the same box for Propane operation.

 

[zox]

Thanks for mentioning the trouble shooting guide. I have looked at it and it doesn't cover much. About the only thing I haven't checked is the solenoids. I'll check them tomorrow morning.