RV Water Heater Fault Light On: What It Means
On this page (5 sections)
The Short Answer: On most RVs, a light that stays on at the water heater’s gas switch is a lockout indicator: the direct-spark ignition tried to light the burner and failed. Suburban’s manual says the heater tries three times, then locks out, and is reset by switching off for five seconds and back on. Check propane, the switch, and the ECO reset first; repeated lockouts need an RV technician.
What the light is telling you
Most RV tank water heaters from Suburban and Atwood/Dometic use direct spark ignition (DSI). There is no standing pilot. When you turn on the gas switch inside the coach, the control board sparks and opens the gas valve. If it senses flame, the burner keeps running. If it does not, it retries and then locks out, and the indicator lights.
The light is about the gas side. A separate electric (120-volt) switch, on dual-fuel models, has nothing to do with this light.
What Suburban says to check
The Suburban SW10 manual (opens in a new tab) lists three items to check before calling a service person when the burner will not come on:
- Switch turned off.
- Gas supply empty or turned off. Check that the propane tank valve is open and the tank has fuel. If the stove lights normally, gas is reaching the coach.
- Reset button on the ECO tripped. The high-temperature limit trips above 180°F on these models and can only be reset once the water is below 110°F.
The manual also notes that the first start-up, or the first after a tank change, may take several ignition cycles before air is cleared from the gas lines. That is handled by cycling the switch, not by opening fittings.
Other common causes
- Low 12-volt power. The ignition board runs on the coach battery. A weak battery or a converter problem can make ignition fail. Check that other 12-volt items work normally.
- Empty tank. Make sure the water heater is full and not in bypass. Running it empty can trip the ECO.
- Blocked burner tube or flue. Insects and nests are common in RV burner tubes. Look through the outside door for webs, nests, or soot, with the switch off.
- Wind. Strong wind into the outside vent can blow out a flame and cause repeated lockouts.
- Worn electrode or failing board. These are technician diagnoses.
Resetting the lockout
Turn the gas switch off, wait at least five seconds, and turn it on. Listen at the outside door for the spark and watch for the burner. If it locks out again after you have confirmed propane, 12-volt power, a full tank, and a clear burner area, do not keep cycling it. Each attempt sends a little propane into the burner area. An RV technician checks the electrode and its gap, the flame sensing, the gas valve, propane pressure at the appliance, and the board.
Related: RV water heater fires up then goes out, Atwood clicking but not lighting, and Suburban not working on gas.
Frequently Asked Questions
Q: Should the light stay on while the water heater is running? A: On most models, no. The indicator signals a lockout; when the burner runs normally it stays off or turns off. Some coaches add their own lighted switches, so check your RV owner’s manual if your light behaves differently.
Q: Does the fault light mean the electric side is broken too? A: No. The lockout light relates to gas ignition. If hot water also fails on electric, troubleshoot that separately; see RV water heater not working on electric.
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 direct-spark-ignition models; other Suburban SW models follow similar operating instructions, but confirm in your manual.
- 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.
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