RV water heater will not light on gas
What this usually means
The gas side of a water heater is a propane burner with a vented exhaust path, and that puts most of this diagnosis with a technician rather than with you. What you can establish — and what genuinely speeds up the visit — is whether propane is reaching the appliance at all, and exactly where in the ignition sequence it gives up.
Check this first
Confirm another propane appliance lights normally. If the stove will not light either, the problem is upstream at the tank, the valve or the regulator, and it is both simpler and cheaper than a water heater fault.
Stop-work system
Gas water heaters involve a propane burner and an exhaust path. Combustion appliances are a technician job.
Nothing below is a repair instruction for this system. What follows is what to observe and record — the work itself belongs to a technician.
Most likely causes
Ordered by how often each one turns out to be the answer, with the tell that distinguishes it.
No propane, or a closed tank valve
most commonOther propane appliances also fail. Frequently after a long gap in use.
Obstructed burner or orifice
most commonClassic after storage — insects nest in burner tubes during the unused months.
Failed igniter or electrode
commonNo clicking or sparking at all when it attempts to start.
Flame sensing failure
commonLights briefly then shuts down, repeatedly.
Tripped high-limit cutout
commonStopped working after an overheat event; some units have a manual reset.
Regulator fault
less commonSeveral appliances misbehave together, often worse in cold weather.
What you can safely check
- 01
Stop immediately if you smell propane
Shut the propane off at the tank valve from outside if you can safely reach it, get everyone out, ventilate, and do not operate switches. A propane smell is not a diagnostic situation.
- 02
Test another propane appliance
If the stove lights, propane is present and the problem is at the water heater. If nothing lights, it is upstream and far simpler.
- 03
Note where in the sequence it stops
Nothing at all, clicking with no flame, or lights-then-drops-out. Those three describe three different faults and reporting which one you have is the most useful thing you can do.
- 04
Look at the exterior vent from outside
Nests, soot or obstruction at the exterior access door. Looking is fine; clearing a combustion path is technician work.
- 05
Check whether a reset has tripped
Many units have a manual high-limit reset. Knowing whether yours has tripped is useful information — but a cutout that keeps tripping is reporting a real fault and must not be repeatedly reset as a fix.
What needs a technician
All of the gas side: burner, orifice, gas valve, igniter, flame sensing and the flue. This is a combustion appliance venting outside the coach, and a fault in the burner or exhaust is a carbon-monoxide risk rather than an inconvenience.
Parts typically involved
So you know what a quote should be naming. We publish no prices — real costs vary by market, season and technician, and a number we invented would look authoritative and help nobody.
- Burner assembly or orifice
- Igniter / electrode
- Gas valve
- Thermal cutoff (ECO)
- Thermostat
- Control board
When to stop troubleshooting
- You smell propane at any point
- There is soot around the exterior vent, or the flame is yellow rather than blue
- It has failed to light repeatedly — every attempt admits gas to a chamber that is not burning it
- A high-limit cutout has tripped more than once
Can you still travel?
No effect on driving. If you smelled propane, close the tank valve and have the system checked before using any gas appliance, including while parked.
Common questions
- Why do RV gas appliances fail so often after storage?
- Because insects — mud daubers and wasps especially — nest in burner tubes and exterior vents during the months the appliance is not used, and it takes very little obstruction to stop a small burner working. It is the single most common seasonal finding on RV gas appliances, and it is why a pre-season check is worth more than the same check in mid-season.
- Can I clear the burner myself?
- It is not owner work, and the reason is specific. The burner sits in a sealed combustion path that vents outside the coach; disturbing or misaligning it is exactly how carbon monoxide ends up inside. Looking at the exterior vent is fine and the information helps. Anything inside the flue or burner assembly belongs to a technician.
Related failures
For the whole system rather than this one symptom, see RV water heater repair.
Next step
Work through structured triage for this system and you will end up with a written service brief: what you observed, in what order, and what has not been established yet. It is the document that lets a technician quote properly instead of guessing on arrival.
Being straight about what this is. No technician is signed to any territory yet — not one. We do not match you, dispatch anyone, or promise a call. What you get is the brief, and a request form that copies it to us so we know the demand is real. If you need someone today, take the brief and send it to a local technician directly; it works just as well that way.