Suburban Water Heater

Is there water in it ???

Can you post model number? Some have a high-limit device that may have to be reset or replaced. If it was run without water, it may have reached that high limit temp.

SW6DE. Did not realize it was electric as well. Need to pay more attention!!!

Take a look at Chris Bryant's Website and down to Water Heaters. You'll see the Service Manual for the "SW" series there. Hopefully the trouble shooting will get you going again. I know that some water heaters use a "one time ECO" (Energy Cut Off - and they use the term for cutting off LPG or AC power). Hopefully something you can reset, or even replace inexpensively without a lot of trouble, will solve the problem. We have SW6DE ourselves and I really like it. Hot water FAST. Only drawback I can think of relative to Atwood is the Suburban uses energy (at least LPG, maybe AC) at the higher rate (BTU, Watts) of the two. But, Hot water FAST.
Glad you noticed "E" for Electric. I've met people who didn't know it offered Electric since it didn't work and they didn't notice the little switch on the left side of the heater panel.

IT being a dual heat WH (electric & propane) it has 2 separate set of t-stats.

Both are under the cover above gas valve in outside compartment.
Both have a high temp t-stat that when it trips can be reset.
On that cover are two buttons to reset high temp t-stat-----push to reset
Left side is for electric and right side is for propane

The high temp t-stat will trip if temp exceeds 170*F (normal should have opened at 130*F). If high trip has tripped and needs to be reset normal t-stat failed.

The electric uses a 120V AC set of t-stats
The propane uses a 12V DC set of t-stats.