10 Reasons Your RV Hot Water Heater Isn’t Working & How to Fix

Last Updated on December 7, 2023 by Jess

Even if you’re hooked up to a campground’s fresh water hookup, you still depend on your RV’s hot water heater to provide you with the hot water you need to shower, wash dishes and clean your greasy hands.

Unfortunately, many water heaters in RVs are relatively small, get a lot of wear and tear over the course of their lives, and can be easily forgotten in the general maintenance routine. No hot water in the motorhome

Did you just turn on the faucet, only to wonder why your hot water heater isn’t working? Whether you only have lukewarm water or no hot water at all in your RV, it can be a frustrating experience.

No one enjoys the surprise of a bone-chilling, teeth-rattling shower, especially in the colder months.

If this is the case, the first thing you should do is check the electrical panel and/or fuse box to make sure there is enough current to spark it or that the electrical element has not tripped a breaker. If you have a propane water heater, you should also check to make sure the gas valve is open.

While these are the two most common and easiest repairs, they certainly aren’t the only reasons your water heater isn’t working.

In order to restore your hot water as quickly as possible, we need to delve a little deeper into how RV water heaters work, some of the possible problems that can cause them to fail, and provide you with a comprehensive troubleshooting guide to help you diagnose and fix the problem with your unit.

How does an RV water heater work?

Some RV water heaters use internal electrical elements to heat the water in the small, insulated tank. However, propane is still the more common fuel for heating hot water quickly. Especially in RVs with large liquid propane tanks. But propane water heaters also usually require an electric ignition system to start the heating process.

Many propane water heaters have some type of pilot light or newer direct spark ignition system to ignite the flame that heats the water in the tank. When in use, the hot water that is removed is replaced with cold fresh water.

This means that the water heater needs time to fully heat the new water before you have hot water on demand again. The larger the tank, the longer it takes to reheat the water. However, propane water heaters typically heat the same amount of water almost twice as fast as electric units.

An electric water heater essentially has a large electrical resistance at the bottom, enclosed in a waterproof housing. The electric current is impeded as it travels through the electrical element, generating heat energy that is transferred to the water. However, this process is slower and can cause deposits to form in the water heater.

10 Common Reasons Why Your Water heater of your motorhome Does not run so well

Besides seemingly simple things like tripped breakers and closed gas valves, there are a few other major causes of water heater failure in your RV.

Accurate troubleshooting is best done with a methodical approach, taking into account the symptoms of the problem.

Even if you can’t fix the problem yourself, knowing why your RV’s water heater isn’t working can save you money on professional repairs.

1. A breaker may have tripped or a fuse may have blown.

If you have an electric water heater in your RV, it can draw a lot of power. A small surge of electricity, such as from a shore power outlet, can trip a breaker or blow a fuse.

In this case, the heater and anything else connected to the circuit is dead. However, many RV manufacturers provide the electric water heater with its own circuit.

If you reset the breaker or replace the fuse and the heater immediately goes out again, you should suspect a problem with the wiring.

A short in a wire or a loose connection causing an arc could just as easily trip a breaker.

It should also be remembered that many modern propane water heaters still require a small amount of power to operate the spark ignition system or automatic pilot light.

These circuits often have multiple appliances connected to them, which increases the risk of an accidental overload that can trip a breaker or blow a fuse.

So you can’t completely rule out a minor electrical problem at the panel just because you have a propane water heater in your RV.

2. the manual gas valve is closed or a problem with the propane system.

The manual gas valve is closed or there is a problem with the propane system

All RV propane water heaters have a main gas valve that must be manually opened and closed. This valve is usually located on the outside of the RV and may also be located near a propane water heater that uses a standing pilot light.

Check this valve from the outside hatch to make sure it is on. If you have a slightly older water heater in your RV, you may need to manually turn the pilot light back on.

If you checked the manual gas valve and it was open but the pilot light did not come on or there was no gas flowing to the burner element, you may have a problem with your propane system.

A kink in the line or forgetting to open the main gas valve on the front tanks may seem like a silly mistake, but you’re not the first or 100th Person who makes it!

3. check the house batteries of the motorhome or the shore power connection.

Check the motorhome's house batteries or shore power connection.

If you have an electric water heater or a newer direct spark propane water heater in your RV, a problem with the RV’s house batteries or shore power connection can interrupt the heating process in the tank.

In such a case, you will notice other electrical problems throughout the RV. The entire motorhome may have no power even though the breakers are connected.

If the house batteries are below 50% or there is a lot of corrosion accumulated on the terminals, the lights in your motorhome may be dim or flickering, and there simply is not enough power to run an electrical element of a DSI water heater in the motorhome.

You will need to either charge your house batteries, use a generator, or talk to campground operators to fix the shore power problem.

4. the bypass valves might still be closed

When draining and disinfecting your RV’s water system during winterization, it is often necessary to close the bypass valve.

This prevents new water from flowing back into the drained water heater. A simple mistake many people make in the spring when they rush to get their RV ready and forget to open the valve again.

Check the bypass valves to make sure they are in the proper position to deliver hot water and fill the tank with fresh water!

5. the igniter may not be centered

Detonator may not be centered

A DSI (Direct Spark Igniter) must be centered and perfectly positioned to start the propane combustion process at the bottom of the water heater.

If you have a bad habit of putting things in the same compartment as the RV water heater, it’s entirely possible that the DSI has been bumped or bent.

If it slipped just a few millimeters out of position, it may be too far from the propane burner to support ignition.

In such a case, the DSI might spark when you turn on the water heater, and the gas will run normally, with the valve open, but the two will not come together to support ignition.

If it looks like it’s a little off-center or you can see a kink in the wire housing, try adjusting it manually with needle nose pliers. Then restart the water heater and observe if the spark and gas are coming together properly.

6. dust & lamp; debris could clog the burner element.

Dust& debris could clog the burner element.

If your propane water heater is on fire but goes out again, it may simply be because dust and other contaminants are preventing the burner from working efficiently. Some even have a safety system built in to stop the flame. However, it is often the case that dust, soot or cobwebs partially clog the burner element.

If your burner looks dirty and won’t burn even though all other systems are working properly, you can clean it with the following steps.

  • Step one: Turn off the circuit breaker for the water heater and follow all other model-specific shutdown instructions in the owner’s manual.
  • Step 2: Carefully remove the cover plate that protects the burner.
  • Third step: Take a photo of the burner unit with your phone before removing it from the gas valve.
  • Fourth step: Locate and remove the combustion door.
  • Fifth step: Slide out the entire burner unit.
  • Sixth step: Blow out dust and soot with compressed air or a compressor. If the soot is stubborn, you may need to gently scrub it off with an old toothbrush.
  • Step Seven: Reassemble the burner and element, using your earlier photo as a guide. Be sure to reinstall the combustion door as well.
  • Eighth step: Turn the RV water heater circuit breaker back on and verify that the DSI ignites the element and that it burns on its own for several minutes.

7. the Hi-Limit/ECO button must be reset

The Hi-Limit/ECO key must be reset

Most RV water heaters have a hi-limit/emergency stop switch. It essentially serves as a fail-safe safety system that shuts off the water heater if the thermostat can’t keep the temperature below a certain level. This prevents some of the catastrophic overheating you’ve probably seen on TV science shows.

When the Hi-Limit ECO turns off the water heater, it will not turn back on until the temperature in the tank has cooled.

Then you must press the orange or red button to reset your RV’s water heater. On most RV water heaters, the reset button is located under a metal plate on the back of the tank or near the thermostat.

Sometimes there are two buttons. One for the electric DSI element and one for the propane burner. If your model has two buttons, you must reset both buttons.

8. your thermostat could be defective

Suppose you find the Hi-Limit/ECO button, press it, and after half an hour or so you have hot water again. Then an hour or two goes by and the water is cold again.

So you go back, press the button again, and everything seems to be working. Only to flush a few hours later with cold water and an inactive water heater and repeat the process.

In a scenario like this, you are probably dealing with a faulty thermostat on your RV water heater. Most people choose to call a professional technician at this point.

If you are handy, you can easily find the replacement thermostat, and if you have the right power tools, you may be able to replace your RV water heater thermostat with the following steps.

  • Step one: Turn off the RV water heater at the circuit breaker and follow any other specific shutdown instructions in the owner’s manual.
  • Step 2: Locate the thermostat housing and remove the cover plate. You may also need to remove some insulation.
  • Step 3: Use a voltmeter or multimeter to make sure there is no residual electrical charge in the thermostat.
  • Fourth Step: Take a photo of how everything is connected to your phone for later reference.
  • Fifth step: Locate the bracket that secures the thermostat. Carefully lift one side of the bracket and gently rotate the water heater thermostat upward. This will prevent the bracket from snapping back into place. Repeat this process on the other side to completely release the thermostat.
  • Sixth step: Disconnect the wires from the thermostat and carefully set it aside. Look for signs of arcing or burned out wires. If there was a short, you may need to replace the wiring before you can install the replacement thermostat.
  • Step 7: If the wiring is OK, you can connect the replacement thermostat and reinstall it in reverse order of how you removed the old one. You can use the photo you took earlier as a guide.
  • Eighth step: Leave the enclosure open, turn the circuit breaker back on, and reset the Hi-Limit/ECO knob if necessary. Then observe the water heater and thermostat to make sure everything is working properly.
  • Ninth Step: If the test cycle is successful, you can close the access door and use the water heater normally.

9. the thermocouple prevents the pilot flame from lighting up.

If you have an older RV, the water heater may use a pilot light to maintain an on-demand flame status. Sometimes the pilot light can go out. Especially if you recently had to replace a propane tank. However, it’s also possible that a lot of dust and soot has accumulated around your water heater’s propane burner element to allow the pilot flame to burn efficiently.

In most cases, you will simply need to relight it. If it does not light, you will need to clean and check the pilot flame and thermocouple with the following steps.

  • Step 1: Open the indicator light. On some models, an access panel must be removed for this purpose.
  • Step 2: Examine the thermocouple near the pilot flame. It looks like a small metal probe with an independent wire connected to the back.
  • Step 3: If the thermocouple is dusty, you may be able to clean it with cotton swabs and a neutral detergent. If it has burn marks, it probably needs to be replaced by a professional.
  • Fourth step: Locate the fasteners that hold the pilot burner and tube in place. If you cannot clean the pilot flame while it is in position, you will need to loosen these fasteners and pull out the entire pilot flame assembly.
  • Step 5: Clean the pilot assembly and tube with compressed air, an air compressor, and other soft tools. You do not want to clean too aggressively and accidentally damage the pilot light components.
  • Sixth Step: Reattach the pilot light and turn on the circuit breaker and propane supply. Then test to see if the pilot flame continues to burn.

10. the element of your electric water heater is defective

If you have an electric water heater in your RV and have tried all other options, the element inside the unit may be defective or dying. They have a limited life span, and the heavy use in an RV can hasten their demise.

Signs that your RV’s electric water heater is defective are often things like:

  • Frequent problems with lukewarm water
  • Small amounts of hot water that then become cold
  • Hot water runs out faster than usual
  • The water heater fuse keeps blowing or the circuit breaker keeps tripping

In most cases, it’s cheaper to simply buy a new water heater than to pay a professional to repair it. Still, you should make sure the element is actually defective before throwing the water heater away and looking for a new one. To do this, you need some basic tools, a multimeter, and the following steps.

  • Step one: Turn off the circuit breaker and follow all other turn off instructions in your owner’s manual.
  • Step 2: Remove the metal jacket surrounding the tank of the electric water heater.
  • Third step: Remove part of the insulation until you find the electric heating element.
  • Fourth step: Make sure that all power is turned off.
  • Fifth step: use a multimeter to check the voltage of the element. If the multimeter gives no reading or gives an erratic reading, the element is probably defective and you will need to get a new one.


The sad truth is that most RV water heaters have a hard life and need routine maintenance to keep them in top shape. This includes cleaning the burner element and pilot light of dust and soot. When inspecting and cleaning, also take the time to make sure your water bypass valves are open.

Make sure your gas valves on the main liquid propane tanks and water heater are also open to ensure a strong flame. If you have a propane water heater and have been using the water heater compartment for storage, take a moment to check the DSI to make sure the spark is close enough to the burner element. It may have simply been bumped and needs to be carefully realigned.

If these relatively simple measures don’t get your RV’s water heater working, you may need to dig a little deeper. Reset the Hi-Limit/ECO knob and test the thermostat. If this doesn’t restore a steady supply of hot water, you may need to replace the thermostat altogether. If you have an electric water heater, you should also take the time to check the element with a multimeter. It’s worth checking this before you replace the thermostat entirely. If the element is dead, consider just buying a new water heater for your RV.

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