Troubleshooting Excel RV Tankless Water Heater that Won't Ignite

Updated 03/10/2026 | Published 03/01/2026

Question:

I bought an Excel water heater from you last fall, model EX93FR. It has been working well, but suddenly wont ignite at all. The D batteries are brand new, so thats not the problem. Do you have basic troubleshooting steps I can follow to narrow down the problem?

asked by: Bill S

Expert Reply:

Hey Bill, if your Excel RV Tankless Water Heater part # EX93FR won't ignite that typically means that there is an issue with the water supply, the batteries (you already checked that), or the propane supply. Have you looked into the other things mentioned at all by chance? First thing that comes to mind for me would be that your propane tank is low or you have a regulator issue. Is your water pump in good shape?

expert reply by: Jameson C

Bill S.

3/5/2026

We tracked down the new problem (where the heater wouldn't ignite at all). Insulation on the wires coming from the D batteries had melted enough to short-circuit the batteries. Now that we have that problem fixed, we're back to the original problem, which is that the heater ignites properly, but the flame blows out erratically, usually so often that it's impossible to take even a small bath. We've measured the propane pressure at the heater with a manometer before and after ignition, so it's not a matter of insufficient gas. Do you know what else could cause this kind of problem?

Jameson C.

3/5/2026

@BillS Did you check the flame sensor? Sometimes if that fouls out it can create weird issues. Taking sandpaper to it will usually fix it.

Bill S.

3/10/2026

I did check the flame sensor; it looked sorta bad, so i filed and sanded it so that it looked clean. But the situation is the same: the burner shuts off after 10 to 40 seconds, regardless of the settings on the two knobs on the front panel. Any other ideas for me to try?

Jameson C.

3/10/2026

@BillS I can't really think of anything off top of my head but I do know that these systems require a lot more maintenance than a regular water heater so if there's any other maintenance that hasn't been done recently I would try that. I know that's not super helpful.