Fixit Yourself: Water Heater Flame Sensor

Standard equipment disclosure first. 2015.5 Lance Model 1995 with Atwood 6 gallon water heater. Atwood has since been bought out by Dometic. Same shit. Different day. Plenty of parts available online. Both OEM and aftermarket.

We spent last weekend at Davis Mountain State Park. We even had shore power to hook up to. Most camping trips for us are to remote places and strictly boondocking. For us, that’s the point. Enjoy having nobody around us for miles. Freedom to let the dogs out without leashes. Our goal for this trip was to hike over the Davis Mountains and into Fort Davis National Historic Site. Reservations were made, electricity was available.

Even though we were at an electric site, I still prefer to use propane to heat the water. Gets hotter faster and seems to recover faster as well during showers. I turn on the water heater.

The usual click click click *whumpf* did not happen. This time it was click click click *whumpf* click click click silence. Uh oh. Not wanting to have to troubleshoot I simply turned off the propane side and and turned on the electric portion of the heater. Problem temporarily solved. Good thing we were at an electric site when this occurred or I would have had to begin troubleshooting right away. We went on to enjoy a fine 4-day weekend with plenty of hiking and relaxation.

Now that I’m home it’s time to troubleshoot. The igniter is working. It lights the flame, but it appears it doesn’t know that it lit the flame because it keeps clicking. Once it senses a flame it should quit clicking (trying to ignite). If it doesn’t sense a flame, it will close the gas valve for safety reasons. Since I know it is in fact lighting, it could be one of two major components: the flame sensor or the motherboard (some call it ignition board). Or the wiring in between any of them.

Trying the easy thing first, I unplug the igniter and pull it out of the fire tube. The flame sensor is part of this. One screw under the L-bracket holds this in place. Easy to remove. Both rods look pretty dirty.Other than that, the ceramic is fine. Wire is fine. I take some sand paper to the rods and shine it up. Everything else looks in tact. I reinstall the igniter and plug it back in. Turn on the water heater and wait.

Click click *whumpf* and stays lit. Fixed!

I got out of jail easy this time.