Atwood Water Heater Won't Stay Lit on Propane
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The Short Answer: When an electronic-ignition Atwood heater lights and then goes out, its control board isn’t detecting the flame, or the flame isn’t getting enough propane to keep burning. Common causes are low or unsteady propane pressure, a dirty or misplaced flame electrode, a blocked burner tube, wind, and a weak 12-volt supply. Try one lockout reset as the manual describes. If it keeps failing, have an RV technician check it.
How the burner proves flame
Current Atwood and Dometic 6- and 10-gallon gas models have no standing pilot. When you turn on the remote switch, the board sparks the electrode, opens the gas valve and then uses the same electrode to sense the flame. If it can’t sense flame within the trial period, it shuts the gas off and turns on the indicator light on the remote switch. A burner that lights for a few seconds and then goes out is usually a flame-sensing or fuel problem. A heater that never lights at all is a different fault, covered in Atwood clicking but not lighting.
Older pilot and pilot-relight Atwoods use a thermocouple, so the causes and parts are different. Check the model on the label inside the outside access door.
What the pattern tells you
| Pattern | Likely cause | Urgency |
|---|---|---|
| Lights, goes out after a few seconds, indicator light comes on | Flame not sensed: dirty or misplaced electrode, poor ground, weak 12 V | Service soon. Don’t keep cycling the switch |
| Runs for a while, goes out when the stove or furnace also runs | Propane pressure drops under load: low tank, regulator | Check your tanks. Technician tests the regulator |
| Goes out mostly on windy days or when parked facing the wind | Wind blowing out or disturbing the flame | Change how you’re parked. Technician checks the flue and door |
| Goes out once the water is hot, and the light stays on | High-temperature lockout | Follow the manual’s cool-down reset once |
| Yellow, lazy flame or soot around the vent | Blocked burner tube (insects) or poor air adjustment | Stop using gas until it’s serviced |
What you can check
- Propane supply. Check that the tank valve is open and the tank isn’t nearly empty, and light the stove to confirm that gas reaches the coach. If the stove flame shrinks when the water heater lights, suspect the supply or regulator rather than the heater.
- The tank is full of water. Check that the bypass valves are set for normal use and that a hot faucet runs steadily.
- Battery condition. A weak house battery or a poorly filtered converter can upset the ignition board. Dometic recommends powering the heater from the battery or the filtered side of the converter. Its troubleshooting notes also flag supply voltage above 14 volts as a problem.
- The vent area, from outside. Look for a wasp nest, a spider web or a storage cover at the outside door’s vent with the heater off and cool. Dometic’s manual singles out insects nesting in the burner tube as a known problem. Don’t clean the burner yourself. Note what you see for the technician.
- One lockout reset. For a failed ignition, the manual says to switch off if the indicator stays on longer than 15 seconds, wait five minutes, and try again. If it locks out again, stop.
What the RV technician will check
The technician will inspect and clean the burner tube and orifice, check the flame electrode for position, gap, cracks and carbon, and confirm the board’s ground connection. They will check the propane pressure while other appliances are running. Dometic specifies 11 inches of water column with three appliances running, which the technician measures with a manometer. They will also check the 12-volt supply at the board, and look for soot or heat damage, which suggests the flame has been escaping the burner tube. If heat has reached the thermal cutoff, the heater may later go completely dead. See Dometic water heater thermal fuse.
Most of these causes are resolved by cleaning or adjustment, or by replacing an electrode, regulator or board. They rarely justify a new heater unless the tank is also leaking.
Frequently Asked Questions
Q: Will a new thermocouple fix it? A: Only on an older pilot model. Electronic-ignition Atwood heaters don’t have a thermocouple. They sense flame through the ignition electrode.
Q: It runs fine on electric. Does that rule out the tank? A: Yes, it shows the tank holds water and the electric side works. The problem is limited to propane, ignition and flame sensing.
Q: Why does it only go out when we’re moving? A: It shouldn’t be running while you drive. Dometic’s manual says to turn the propane off at the tank while the vehicle is moving, because wind currents can push the flame back into the burner tube and open the thermal cutoff. If you have a different RV heater brand with the same light-then-out pattern, see RV water heater fires up then goes out.
Manuals and supporting references
These links distinguish general safety information from model-specific documentation. A manual directory helps you locate your unit’s instructions; it does not establish that every model uses the same parts, codes, or test values.
- Dometic (Atwood) water heater models 4, 6, 10 operation manual (MPD 93756) (opens in a new tab)Atwood/Dometic 4-, 6- and 10-gallon pilot, pilot-relight and electronic-ignition models.
- Dometic: product support (opens in a new tab)Product manuals and support for Dometic equipment; confirm coverage of any legacy Atwood model.
- PG&E: recognizing and responding to a gas leak (opens in a new tab)Emergency actions for suspected fuel-gas leaks.
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