RV Water Heater Won’t Ignite
When an RV water heater clicks but will not light—or does nothing at all—the problem may involve propane supply, 12-volt power, the igniter, wiring, safety devices or the control board.
Common RV Water Heater Ignition Problems
No Propane Supply
An empty cylinder, closed valve, regulator problem or interrupted propane supply can prevent ignition.
Low 12V Power
Most RV water-heater control systems depend on 12V DC power even when heating with propane.
Igniter Problem
A damaged electrode, incorrect gap, poor ground or wiring issue may prevent a reliable ignition spark.
Control Board
The control board manages the ignition sequence, but it should not be assumed bad until its inputs and outputs are tested.
Gas Valve Circuit
The propane valve must receive the proper electrical command and operate correctly for burner ignition.
Safety Device
High-temperature limits, thermal cutoffs and other safety circuits can interrupt water-heater operation.
What Happens During the Ignition Sequence?
Although designs vary, a typical propane RV water heater receives a call for heat, verifies the required electrical conditions, opens the gas valve and produces a spark at the burner.
The control system then looks for evidence that the flame has been established. If the sequence fails, the system may shut down and attempt ignition again or enter a lockout condition.
What We Check During Diagnosis
- 12V power to the water heater
- Applicable fuses and electrical connections
- Propane availability
- Ignition spark
- Igniter/electrode condition
- Ground connections
- Gas-valve operation
- Control-board inputs and outputs
- Thermal cutoff and safety circuits
- Burner condition and visible obstruction
The objective is to identify which part of the ignition sequence is failing instead of replacing components based only on the symptom.
Water Heater Clicks but Does Not Light
Hearing the igniter clicking tells us that at least part of the ignition sequence is occurring, but it does not prove propane is reaching the burner or that the flame is being established.
Diagnosis may involve determining whether there is a proper spark, whether the gas valve is being energized and whether propane is actually reaching the burner.
Water Heater Does Nothing
If there is no click, spark or other response, the diagnostic path may begin with 12V power, fuses, switches, wiring, control inputs and safety devices.
Replacing an igniter usually will not fix a unit that never receives the electrical command to begin the ignition sequence.
Water Heater Lights and Then Shuts Off
A burner that lights but quickly shuts down can have a different problem than a burner that never lights.
Possible causes can include flame-sensing problems, electrode condition, grounding, control-board issues or unstable propane combustion.
Does a Failed Ignition Mean the Control Board Is Bad?
No. A control board is only one possible cause.
Low voltage, bad grounds, propane supply problems, igniter issues, wiring faults, safety devices and gas-valve problems can all produce symptoms that resemble a failed control board.
Tankless RV Water Heaters
Tankless systems use different controls and operating sequences than traditional tank-style water heaters. They may also provide fault codes that help narrow the diagnostic path.
The specific manufacturer and model number are especially useful when troubleshooting a tankless unit.
Mobile RV Water Heater Diagnostics
MilTech RV provides mobile diagnostics and repair for common tank and tankless RV water-heater problems, including ignition failures, electrical heating problems, controls and leaks.
Learn more about MilTech RV Water Heater Repair & Diagnostics →
Service Areas
MilTech RV provides seasonal mobile RV service in Greater Des Moines, Iowa and Yuma, Arizona .
RV Water Heater Won’t Light?
Tell us your RV year, make and model, water-heater manufacturer and model number, whether it is tank or tankless, and exactly what happens when you call for hot water.
Request RV Service Call/Text 515-257-6021