rv water heater not lighting

RV Water Heater Not Lighting- Fix It Before Panicking!


On a chilly winter day, you’re on a trip with your precious RV that made you an experienced traveler. You get into the shower to turn on your water heater. 

But alas, you see the RV water heater not lighting. And there you go, a barrier to the beautiful time that you planned for so long.

Dear reader, we know how comfortable the warm bath would be. Worry not, because we are here to help you get that RV water heater running right away.

All you have to do is stick with us for the sake of that warm bath that you’ve missed. So, let’s go-

How Does an RV Water Heater Work?

When it comes to RV water heaters rather than the regular home water heaters, you should know that propane is the element that powers it up generally. 

However, certain RV water heaters use electricity too. If you don’t know which one is used for yours, you might determine it from RV’s manual. 

You see, pilot lighting is the most common among the RV water heaters. Some models even come with immediate spark ignition. 

Just like the water heater of your home, the RV water heater has a built-in safety system to ensure safety when you have uncontrollable pressure or heat building up.

When you activate the switch from the inside, the signal passes to the control board. The control board tells the system what to do. 

There are basically two options for you when lighting the water heater; electrical and gas. So, you might be wondering what happens for each of them.


If you turn the switch to electric, the signal will pass to the control board first. The control board will pass the signal to the thermal fuse, which is attached to the thermostat. 

It’ll then send back electricity through the control board to heat the water for your healthy, warm shower or wash. 


When you switch to gas, the signal will be transmitted to the control panel just like it does for the electricity. However, this time the signal will be passed to the E.C.O. 

E.C.O is basically a protection switch which protects the system when the temperature is over 160 degrees. Now, electricity will pass through to the gas valve, which will activate the solenoid.

This specific activation will allow the gas to pass through the tube you see near the gas valve. Once gas passes through the tube and the solenoid’s activated, the sparker will spark three times. 

The spark and the gas will create a flame, which will send a signal back to the control board. That is the “It’s going fine” signal. 

Reasons Why the Water Heater’s Not Lighting

There are several reasons for your water heater lighting issue. But we won’t know the real problem if we don’t open up the control panel cover.

So, let’s explore all the possible reasons for the issue that you’re facing-

Spider Web

If your RV has been sitting in a place for a long time, there’s a high chance that it’ll become home to various animals if it’s kept in the open. And spider nests are the most common in this case. 

Often the spiders get into the control panel cover and build their nest around the spark plug. This hampers the spark plug from lighting. 

Dust and Corrosion

If you don’t do proper maintenance once in a while, there’s a high chance of dust and corrosion at the water heater’s technical parts. 

This contains the thermal fuse covered in dust and the tube getting all rusty with time. These things cause the water heater to malfunction. 

Moreover, dust near the spark plug and other connections might influence the malfunction. 

Damaged Spark Plug

The spark plug usually sparks three times when you need the heater to light. And there are cases when the spark plug cracks because of aging. 

You see, whenever you light the water heater, the spark plug wears out a little. Sometimes it cracks because of it and becomes unable to spark anymore. 

RV Water Heater Not Lighting- How to Fix It?

As there are several reasons, obviously there’s going to be several solutions. Luckily, you don’t need to go on a search for the different solutions because we got it all here today.

Moreover, we turned them into steps so that you can easily identify the problem. 

Step 1: Turn Off Gas and Electricity

It should be considered your duty to turn off the gas and get rid of electricity while working. We don’t want to get electrocuted or waste some gas while you’re in the process. 

Step 2: Proper Cleaning

Proper maintenance might have kept you a thousand miles away from the hassle that you’re facing right now. 

However, let’s bring out what you can do now rather than bringing out what you could’ve done. So, you need to grab a brush and clean the whole area. 

The thermal fuse is the first thing that needs attention for proper cleaning. So, unplug it and clean it carefully. 

Check the thermal fuse if it’s fused or not. Then, check for continuity of the electricity using a multimeter. 

If there’s proper continuity of electricity, move on to the next step. If the fuse is not showing continuity, you need a replacement. 

Step 3: Check the Spark Plug

Now the final attention on the spark plug area. So, you need to open the spark plug and check for corrosion or damage. 

Check the sparker and the grounding rod. If there’s an issue with them, it’s better to order a new spark plug. Because you will need to change them sooner or later. 


See, it was like elementary school for you. You just needed to find the reason for the RV water heater not lighting and fix it according to it. 

A word of advice for you, please have proper maintenance of your RV. With proper care, it’ll give you the best experience you’ll be able to cherish for a lifetime. 

So, we wish you the best of luck and hope you fix the water heater right away.

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