RV Water Heater Lights Then Goes Out: Causes
On this page (5 sections)
The Short Answer: When an RV water heater lights, burns for a few seconds or minutes, then shuts off, the burner either lost its propane supply or the control stopped sensing the flame. Low propane or a struggling regulator, wind at the outside vent, high altitude, a dirty flame sensor, and an overheat cutoff are the usual causes. How long it runs before going out points to which.
Use the timing as a clue
| What happens | Likely cause |
|---|---|
| Lights, goes out within a few seconds, retries, then locks out | Flame not sensed: dirty or misaligned sensor electrode, weak ground, or an unstable flame |
| Runs a minute or more, goes out when the furnace or stove also runs | Propane supply cannot keep up: low tank, freezing regulator, undersized or failing regulator |
| Goes out mostly on windy days | Wind at the outside vent blowing out or lifting the flame |
| Started after driving into the mountains | Altitude; the burner may need derating |
| Runs a long time, then stops and will not restart | High-temperature cutoff (ECO) tripped |
Owner checks
- Propane level and valve. A tank that reads low, or a regulator coated in frost on a cold day, can supply enough to light but not enough to keep burning.
- Other propane appliances. If the stove flame shrinks when the water heater lights, the supply is the problem.
- The outside vent. Suburban’s manual warns that the vent must not be blocked by an open door on the RV. Also check that no awning, skirt, or object sits close to the vent.
- The burner area, with the switch off. Look through the outside access door for webs, nests, rust flakes, or soot. Insects nest in burner tubes often enough that RV technicians check it on every service.
- The ECO. On Suburban SW10 models, the manual says the high-limit trips above 180°F and resets only after the water cools below 110°F. If the reset button has tripped, find out why before resetting it more than once; an empty tank is a common reason.
High altitude
Suburban rates its heaters for operation without modification up to 4,500 feet. Its manual (opens in a new tab) says that above that, the burner may need derating (about 4 percent per 1,000 feet) and that an underderated burner can lift off or burn yellow and sooty, which is also a carbon monoxide concern. Changing the orifice is a dealer or service-shop job, and it must be reversed when you return to lower elevations.
What the RV technician checks
The technician checks propane pressure at the appliance while other appliances run, inspects the regulator, and examines the electrode: its gap, its position in the flame, cracks in the ceramic, and the ground connection that completes the flame-sensing circuit. They clean the burner tube and orifice, confirm the flue is clear, and test the ECO and the control board. On older pilot-type heaters, they check the thermocouple instead.
Most of these are minor repairs: cleaning, an electrode, a regulator, or an ECO. A replacement control board is a larger part but still far less than a new heater.
Related: RV water heater fault light, Atwood water heater won’t stay lit, and Dometic water heater thermal fuse.
Frequently Asked Questions
Q: Can I keep the water heater running on electric instead? A: On a dual-fuel model, yes, as long as the tank is full. Electric operation does not fix a gas problem, and it does not rule out a propane leak, so still have the gas side checked.
Q: Does it need a new thermocouple? A: Only older standing-pilot RV heaters use a thermocouple. Direct-spark models from Suburban and Atwood/Dometic sense flame through an electrode and the control board, so a thermocouple is the wrong part.
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.
- Suburban: SW10D/SW10DE/SW10DM/SW10DEM installation and operation manual (copy hosted by Forest River) (opens in a new tab)Suburban SW10 DSI models: high-altitude derating, vent placement, and ECO limits; confirm details for other models in their own manuals.
- Suburban: service and support (opens in a new tab)Identify the appliance behind the RV badge and obtain its operating instructions.
- 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.
Editorial standards and corrections · Prepare a useful service request