Just a tip. On our recent road trip, the propane part of the water heater would not light on day 3. Investigation revealed that the lower electrode connected to the metal frame which the upper electrode arcs to was out of range to far to arc and light. I moved it to the correct distance ( I believe 3/8 inch gap per manual).
The pilot lit immediately and problem solved. I suspect some of the bouncing on the Northeast roads caused it to move away slightly. Easy fix if you get a constant fault code light.
Hope this helps someone avoid a service visit