RV water heater igniter not clicking or won’t light on gas

Common symptoms

• You turn on the gas switch and hear nothing from the heater: no clicking, no whoosh.
• It clicks for a few seconds, goes quiet, clicks again, then gives up.
• A red lockout light comes on at the inside switch panel.
• The burner lights with a soft whoosh, then goes out.
• A tankless unit shows E1 on the wall panel or blinks a red LED.

Quick checks before anything else

• The gas switch for the water heater is on.
• The propane tank has gas, its valve is fully open, and a stove burner lights.
• If you just refilled or swapped tanks, run a stove burner for a minute first.
• The water heater fuse on the 12V panel is good.
• The battery reads about 12.6 volts.
• On a Suburban, the red ECO reset button has not tripped.
• The burner tube and vent behind the outside door are free of nests.

What causes it?

• No 12V to the board A switch, fuse, weak battery or loose wire means no clicking at all.
• ECO or thermal cutoff open A tripped high-limit or a melted thermal cutoff breaks the circuit, so nothing happens.
• Air in the propane line It clicks but runs out of tries before gas reaches the burner, common after a refill.
• Nests in the burner tube Spiders and mud wasps block the gas and air mix, causing delayed or no ignition.
• Electrode problem A cracked electrode or wrong spark gap gives weak or no spark at the burner.
• Low gas pressure or a bad gas valve Clicking with no flame while everything else checks out.

How the water heater lights

Most RV tank heaters use DSI (direct spark ignition): a control board makes a spark each time the burner needs to light, with no standing pilot flame. Knowing the order of events tells you where it stops.

Step-by-step: finding why the igniter won’t click or light

When your RV water heater igniter is not clicking, power is the problem. When it clicks but the burner is not igniting, gas, the burner or the spark is the problem. Do the steps in order, because a weak battery can fake both.

1. Watch one full try Open the outside door, turn the gas switch on, and watch and listen. Note if you hear clicking, if you see a flame, and if a red light comes on inside. No clicking at all points to steps 3 to 5. Clicking with no flame points to steps 2 and 6 to 8.
2. Light a stove burner first After a refill, a tank swap or storage, the line can hold air, and the heater only sparks for a short time per try. Run a stove burner until its flame is steady, then reset the heater. Suburban says the first start-up may take several ignition cycles to purge the air. On Dometic (Atwood) 4, 6 and 10 gallon DSI models, if the switch light stays on longer than 15 seconds, turn the switch off, wait 5 minutes, and try again.

   

3. No clicking: check the switch, fuse and battery The board needs 12V DC even on propane. Check the water heater fuse on the 12V panel, then measure the battery: about 12.6 volts at rest is healthy. Dometic boards have their own 2 amp mini fuse, and Dometic says never to fit one over 3 amps. Too much voltage stops them too: Dometic says to check that supply voltage is not over 14 volts. If the battery is low, our RV converter guide shows how to test the charging side. Never run the heater from a battery charger alone; Dometic warns against it even for testing.

   

4. No clicking: check 12V at the heater A good battery does not prove power reaches the board. With the switch on, measure at the heater’s 12V connection. It should read close to the battery voltage. If it reads zero, trace the fuse, switch and wiring. If it is much lower, look for a loose or corroded connection or ground.
5. No clicking: the ECO and thermal cutoff On a Suburban, a tripped ECO is one of the three things the manual says to check before calling for service. It trips above 180°F, and you push the red button once the water is below 110°F. Dometic heaters have a thermal cutoff in the power line that melts if burner heat reaches it, for example when the flue tube is blocked. Dometic says the blockage must be cleared and the cutoff replaced before the heater will run again.
6. Clicking, no flame: clean the burner tube Turn the heater off, close the gas, and let it cool. Dometic warns that spiders and mud wasps nest in the burner tube, causing delayed ignition or ignition outside the combustion tube. Its owner steps: remove the air shutter screw, slide the shutter down, run a flexible wire brush through the tube until you can see it at the far end, vacuum where the burner enters the combustion tube, then put the shutter back. The orifice, tube and shutter must line up.
7. Clicking, no flame: inspect the electrode The electrode is the metal rod in a white ceramic insulator that sparks at the burner. With gas and power off, look for cracked porcelain. Dometic sets the gap between the electrode and its ground at 1/8 inch. Girard lists the wrong distance between igniter and burner, and dirt between them, as causes of failed ignition, and says to check that the spark cable is secure and not shorted to metal. The Suburban owner’s manual gives no gap, so check your model’s service information.
8. Clicking, no flame: gas pressure and the gas valve If the spark is good and the stove lights, the heater may not be getting enough pressure. Dometic says gas pressure should be set at 11 inches of water column with three appliances running, measured with a manometer (a low-pressure gas gauge). Girard specifies 11 to 14 inches. Suburban says not to try to repair the gas valve. Both jobs belong to a tech, and any fitting that is opened needs a leak test.
9. Keeps trying, then locks out Three tries and a lockout is the board doing its job. Reset it once, then find the cause from the steps above. On a Dometic XT running gas and electric together, a gas lockout does not light the red lamp, because the electric side is still working. Turn the electric switch off: if the lamp comes on, the gas side has locked out.
10. Tankless: read the code Girard and Furrion show E1 when the burner fails to light after two tries, and E2 when the flame goes out while running. Turn the hot faucet off and back on to reset. E8 means the air pressure switch saw no airflow, so check the vent for nests. Look up yours in the Girard GSWH-2 code list. On a Truma AquaGo, the red LED blinks code 1 after three failed tries about 30 seconds apart, code 24 for low voltage, and code 28 for low gas pressure. Count the blinks with our Truma AquaGo blink codes.

Lockout and reset by brand

The same propane causes, like air in the line and low pressure, also stop furnaces. If your furnace ticks without lighting too, see RV furnace clicking but not igniting. For how the other heater parts fit together, see our RV water heater repair guide.

When to call an RV tech

• 12V is good at the heater and the ECO is fine, but it still will not click. The board may be at fault.
• The electrode needs regapping or replacing and you cannot reach it safely.
• Gas pressure needs testing, or the gas valve is suspect.
• A Dometic thermal cutoff has melted, or the board fuse blows again after you replace it.
• The flame is yellow, you see soot, or ignition is delayed.
• A tankless code keeps coming back after one reset.

If the heater lights but you still get no hot water, go back to RV water heater not working on gas or electric.

Common questions