RV Water Heater Not Working

Check these first, in this order

1. 1

   Cause 1: The bypass valve

   If you winterized, the bypass valves may still be routing water around the heater. Suburban's winterizing advice is to use a bypass kit to isolate and drain the heater and leave it bypassed while antifreeze is in the system. That's correct for storage, and it also means the tank stays empty when you get back on the road.

   Look at the back of the heater, usually through a hatch inside a cabinet or under a bed. Set the valves to normal flow, then open a hot tap until water runs steadily with no sputtering. Only then turn the heater on. Skipping this step is an easy way to burn out a brand-new element.

   A bypass valve that's partly open, or has a leaking seal, causes a different symptom: water that's only lukewarm, because cold water is mixing into the hot line.

2. 2

   Cause 2: Is there water in the tank?

   Related but worth its own check. After draining, refilling or a long trip without water, the tank may be partly empty. Open the relief valve lever on the outside panel for a second. Water should come out, not just air. Suburban spells out why it matters: running the gas side dry can melt the insulation jacket and trip the ECO, and running the electric element dry will damage it.

3. 3

   Cause 3: Propane supply

   Check the tank gauge or lift the tank to feel the weight, and make sure the tank valve is fully open. Then light the stove. If the stove won't light either, the problem is propane supply, not the water heater. After a tank swap, air in the line can take a few tries to clear. Light the stove first to purge it.

4. 4

   Cause 4: Battery power

   This one surprises people. A gas RV water heater still needs battery power to run its ignition and controls. Most modern Suburban heaters use direct spark ignition (DSI) or electronic ignition, so there's no pilot to light by hand. A weak house battery can make the igniter click without ever lighting the burner. Check the battery voltage and any fuse for the water heater circuit.

5. 5

   Cause 5: The igniter and lockout

   Go outside, open the water heater access door and listen while someone turns the heater on. You should hear clicking and then the burner whoosh. Clicking with no flame points to gas supply, a dirty or misaligned electrode, or air in the line. No clicking at all points to power, a loose wire or the control board.

   Most DSI systems stop trying after a few failed attempts and show a fault light. Turn the switch off and back on to try again. If it locks out repeatedly, stop resetting it and get it looked at. Older pilot models follow the lighting steps on the label or in the owner's manual. See our page on water heater igniters for how spark ignition fails.

6. 6

   Cause 6: The electric side: breaker, switch and element

   On electric mode, the heater runs on shore power or a generator through the RV's breaker panel. Suburban's E-Series heaters, for example, are 120-volt electric units. Check that:

   • you're plugged into a live pedestal or the generator is running
   • the water heater breaker in the coach panel hasn't tripped
   • the electric switch for the water heater is on (it's often separate from the gas switch)

   If all three are fine and the gas side works but electric doesn't, the element is the likely failure. An element that was run dry is usually done. You can test it with a multimeter with the power off, the same way as a home heater element. See how to test a water heater element.

   Many models can run gas and electric at the same time for faster recovery. If you only get hot water with both on, one side may be weak.

Other common complaints

The relief valve drips

This is usually normal. Suburban explains that heated water expands in the closed RV system and the valve releases that extra pressure. Its fix is to restore the air pocket at the top of the tank: with the heater off and the cold supply shut off, drain a little water through the relief valve. If it keeps weeping, a dealer can add an expansion or accumulator tank on the cold line. More on relief valve leaks.

Rotten egg smell

Suburban calls it harmless and says it comes from chemical action or bacteria in the water. Its remedy is to chlorinate the tank: add about six ounces of household bleach per 10 gallons of tank water, run it through every faucet, let it sit a few days and flush. See water heater rotten egg smell.

Popping, rumbling or rusty water

That's usually sediment or a worn anode rod. Suburban heaters use an anode rod, and Suburban says to check it every 6 to 12 months and replace it annually or when more than 75% of the rod is consumed. It comes out with a 1-1/16" thin-wall socket. Water high in iron or sulfates eats it faster. Our anode rod guide has more.

Tank, tankless and replacement

Suburban's tank heaters come in 4, 6, 10, 12 and 16 gallon sizes. Its tankless RV unit puts out up to 60,000 BTU per hour. If you're replacing a heater, the size of the cutout in the sidewall matters. Suburban notes that going from a 10-gallon to a 12-gallon unit needs 1 3/4 inches of additional space.

When to call an RV technician

Call when:

• you smell propane
• the burner lights but the flame is yellow, sooty or rolls out of the burner tube
• the DSI board keeps locking out after the gas and power checks pass
• the tank itself is leaking

Gas valves, control boards and burner work on RV heaters are technician jobs. A mobile RV tech can often do this at the campsite. Suburban's support line and dealer locator are on its service page.