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RV Hot Water Heater Troubleshooting 101


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RV Hot Water Heater Troubleshooting 101

If you are on the road in your RV make sure you don’t end up taking cold showers. Whatever your RV water heater problems are we’ve got you covered with our top tips and guide for RV hot water heater troubleshooting.

Hot Water on Tap

Camping in the wild can be a lot of fun, but if you’re traveling in a recreational vehicle (RV), then you’re most likely looking forward to a nice shower at the end of the day.

And nothing is more shocking than that first cold spray you discover when your boiler isn’t working!

You might be worried that calling a plumber or mechanic will lead to expensive repairs or even a replacement. But before you contact the professionals, try some RV tankless hot water heater troubleshooting. The problem might be easier to solve than you think.

If you try these simple steps, you might be taking that hot shower after all.

All you need to know about RV hot water heaters:

  • Diagnosing common issues
  • Troubleshooting for RV hot water heaters
  • Proper maintenance
  • How to winterize your heater

RV Hot Water Heater Troubleshooting

There are many different problems that you can experience with your RV hot water heater. Whether your RV propane water heater won’t light, or you need ideas for RV electric water heater troubleshooting, this guide can help.

If Your RV Hot Water Heater Makes Noises

Nobody wants to visit a mechanic and try to recreate the noises they hear coming from their vehicle. Here we discuss three of the common noises associated with an RV water heater not heating and what you can do about them.

For safety’s sake, ensure you turn off and unplug electric heaters, or for a gas unit close the propane tank gas supply valve.


Screeching noises can happen when pressurized water is being forced through tight spaces. These tight spaces can be kinks in flexible pipes or improperly functioning valves. First, check the hose connections to your unit, and then ensure that the valves are fully opened. 

The valves should always be fully open or fully closed—these are shutoff valves, not flow regulator valves. Do not try to limit hot water flow with these knobs.


Popping or cracking sounds can come from your RV boiler when liquid gets trapped against the heating element.

Minerals and other naturally occurring (but safe) elements can precipitate when the RV hot water heater element is turned off. These minerals settle on the heating elements, and this is called scaling. Scaling also traps liquid against the heating elements and prevents flow across them.

When the RV heating element gets hot again trapped water will boil and evaporate, bursting from the scaling (much like moisture explodes inside popcorn). This causes popping sounds.

Hearing these sounds means that your heating element needs to be cleaned. Flush the unit with a deliming solvent, this should dissolve the mineral scaling and expose the heating elements for proper operation again.

You may need to think about replacing the element if none of the above works. You can also prevent or delay this scaling by filling your tank with soft water. 


Whistling sounds come from escaping air or steam. There are a few places that you should investigate if you hear whistling.

First, you should check the drain valve at the bottom of the tank. As your unit ages, the drain valve can become loose and allow air into the tank. Tighten or replace this valve to stop the noise and prevent problems that come with air incursion.

Second, check the temperature pressure relief valve. This pressure valve is a safety device that allows steam to escape when the unit overheats. If this valve is frequently whistling, this is an indication of severe and hazardous problems with your unit. In this circumstance, you should have a professional inspect your heater to avoid dangerous accidents.

Third, check the tank for cracks in the walls. A cracked tank or body may allow compressed air and steam to escape. There is no recommended way to repair these cracks, and RV water heaters should be replaced if it’s in this condition.

If the Pilot Light Goes Out

This problem only applies to a gas heater. When you find your RV hot water heater not lighting you may be able to light the propane burner manually.

The pilot is supposed to stay lit as long as your unit is connected to an LP source. However, like any small flame, it can go out. First, you should check to make sure your LP source is still providing gas. Check your LP tank and gas line, and make sure the valves are open. 

If the gas is working, you can relight the pilot burner orifice with a stick lighter, the same kind that you use to light your outdoor grill.

If the pilot continues to go out without a discernible reason, this may be an indication of a bad thermocouple. The thermocouple is a relatively inexpensive part, and you can usually replace it yourself with a common household toolbox.

If Electrodes Don’t Spark

Some gas heaters use electrodes to ignite the gas, rather than a pilot. You can hear these electrodes sparking when you turn it on. If you don’t hear sparking noises, then most likely, your unit won’t light.

Check the power source for the electrical igniter. In some cases, the electrodes are powered by D-cell batteries, which might need changing. Also, check the circuit board for loose wires.

If your gas boiler also has an electric plug, check the cord and plug, and also check the circuit breakers to ensure the outlet is working. If the current supply is in good condition, then it’s time to replace the electrodes.

If the Gas Burner Fails to Ignite

If your LP heater isn’t igniting, the first thing you should check is your supply. Make sure the valves are open, and your propane tank isn’t empty.

If the pilot lights working, this means you have propane. Alternatively, if you know, you have propane, and you hear the electrodes sparking, those electrodes might be grounding without igniting the gas.

To troubleshoot the gas electrodes, first shut off the gas valves. Next, run your hot water so that you can hear the electrodes sparking, and search for the spark. You might find loose wires that are grounding the sparks in the wrong location.

If There’s Not Enough Hot Water

A shortage in your RV can be attributed to a few different causes.

First, if your unit has temperature and flow settings, you can try to adjust these settings to solve the problem.

If that doesn’t work, it’s time for some in-depth troubleshooting.

First, you may have sediment collecting at the bottom of your unit’s tank. This sediment covers the heating elements and prevents them from heating. Sometimes, flushing your boiler tank with high-pressure soft water or deliming solvent can remove this sediment.

Second, you may have a malfunctioning dip tube. The dip tube is located at the top of the heater unit where cold water enters. Its purpose is to pipe liquid with enough pressure into the unit to mix the contents so as to equalize the temperature inside. Sometimes if it becomes clogged or kinked, the temperature inside becomes stratified, and the hot water becomes stuck at the bottom of the tank.

Third, if something is genuinely broken inside the unit, it will be one of these three parts: the thermal switch, the thermostat, or the heating element. Any of these parts can be replaced without replacing the entire boiler. We recommend that you hire a professional for a problem-free replacement on these parts.

If You Find Soot

Soot is caused by incomplete gas combustion. This is usually a result of improper gas and air mixture.

The problem can usually be solved by clearing the main burner and the air intake, making sure that there is no build-up of material restricting the airflow or the gas flow.

You should also check the air outtake (or chimney). If this becomes obstructed, it can lead to a build-up of carbon monoxide. This can become hazardous, especially in the confined space of an RV. This excess carbon monoxide can also result in incomplete combustion, which leaves behind soot. 

If you have checked all of these points and you still find your RV heater not working, it’s time to call a professional in. Improper combustion is not a problem that you want to leave unchecked for safety reasons.

If There’s Improper Ignition

Any time you suspect that your gas (LP) heater is not igniting correctly, follow these steps:

  1. Check the power to the unit—the batteries, if battery-powered, or the fuse box/circuit breaker if it is plugged in.
  2. Check the gas valve and make sure it’s fully opened by twisting the knob to the left as far as you can.
  3. Tighten the thermocouple. You can find the thermocouple by opening the front access panel. The thermocouple is around the pilot burner assembly. Tighten it with your fingers first, and then with a final quarter-twist with a wrench.
  4. Check for escaping gas by smelling the air around your heating unit. This can be a potentially dangerous situation, and you should call a professional if you smell gas.
  5. Adjust the thermostat to the lowest setting, or the “Pilot Light” setting if you have it.
  6. Turn the gas control knob to “Off.” Open the access door to the outer burner, which is usually underneath the unit. Wait for a few minutes for the external gas to dissipate and for the gas pressure to build up.
  7. Turn the gas knob to “Light” and press the ignition button several times, listening and watching for an electric spark.
  8. Push the gas knob fully open, and press the ignition button again until the pilot lights. Once lit, you can close up all of the open access panels and set the RV water heater thermostat.

If You Smell Rotten Eggs

Any “rotten egg” smell that you might detect is from anaerobic bacteria in the water supply. The bacteria reacts with sulfur and other materials that the anode rod is made from. This reaction produces hydrogen sulfide, which smells like rotten eggs.

This is a problem with the water, not your heating unit. However, a few tips can mitigate or eliminate the smell:

  • Don’t merely remove the anodes. This might solve the smell, but it will lead to future problems.
  • Flush the system with hydrogen peroxide for a quick, temporary fix.
  • Replace the anode rod with aluminum/zinc compound anodes. This material will not produce smelly hydrogen sulfide.
  • Contrary to common sense, soft water may actually smell worse and you may need to buy powered anodes to eliminate the bad smell completely.

RV Water Heater Maintenance

How to Properly Drain

Periodic draining is an integral part of RV water heater maintenance, simply follow these simple steps:

  1. Close the water supply by twisting the knob to the right.
  2. Turn off the unit by disconnecting the breaker (if electric) or shutting off the propane (if gas).
  3. Locate the drain valve underneath the heater and attach a normal garden hose to it.
  4. Open any hot water faucet in your motorhome. This will release pressure on the system.
  5. Open the drain plug to drain the hot water tank.
  6. When fully drained, reverse these steps to refill and begin using it again.

How to Winterize Your Water Heater

When preparing your travel trailer for the cold off-season, follow these steps to protect your RV heater:

  1. Turn off and unplug from the electrical power (if electric). If it’s a gas heater (on-demand) close the propane system valve.
  2. If it’s electric, wait about 30 minutes for the heater to cool down. A gas model should not be hot unless it was recently used.
  3. Turn off the pump. Close the supply valve so that no more water enters.
  4. Open the drain valve and water pressure release valve.
  5. If you have a water heater bypass valve, open this valve to continue winterizing the rest of your RV plumbing system.

How to Annually Check the Anodes

Your heater anodes should be annually checked and replaced when necessary. This will reduce the need for lots of maintenance and repairs.

  1. Turn off the water by closing the shutoff valve. Turn off the power or gas also.
  2. Drain the tank using the steps mentioned above.
  3. Locate the anode rod, which is most likely on the top of the heater unit.
  4. Remove the anode with a socket wrench or box wrench.
  5. Do not use any lubricants or loosening fluids on the anode, which could contaminate your supply.
  6. Install new anodes. As mentioned earlier, aluminum-zinc or powered anodes will reduce foul odors.
  7. Turn on the gas/electricity and the water.


We hope this article has given you some great tips if you find your RV electric water heater not working or you need to do some RV gas water heater troubleshooting. Follow this advice, and we’re sure you will be enjoying a nice hot shower in your RV. 

If you found this article useful, please feel free to share it with other campers, friends, and family members. We welcome your comments in the comment section, especially if you have any personal experiences to share with other visitors!

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