Your RV water heater is such a luxury when you need hot water. But what should you do if all you have is cold water and your RV water heater fires up and then goes out?
Since your RV water heater does start up, that is a good sign that the electrical components are working. And the issue is more related to the fuel or flame.
This post will review the common causes your hot water tank goes out and the best solution, including:
- Flame
- Propane and Fuel Source
- Ignition Failure
- Thermocouple
Since a vast majority of travel trailers and RVs have a water heater tank, this post will focus on heaters with a tank and not tankless water heaters.
Table of Contents
Flame
Since your water heater fires up, that is a good sign that most of the electrical components are working. This means that your switch is working, and the ignitor is trying to start and keep the water heater going.
When the water heater fires up and then goes out, it is most likely a flame issue. The water heater has many safety features that protect RVgoers from overheating or dangerous unburned propane.
Knowing this is a flame issue, let’s focus on troubleshooting those components.
Propane
The first step in an RV, without any heat, is to check your propane. Most RV heater tanks use propane as a fuel source (some strictly only use electricity).
Check to see if your propane tank is empty. With the tank secured to your RV, it is sometimes difficult to tell, and gauges are not usually 100% accurate.
A water heater needs a fair amount of gas flow to operate and provide heat. If your propane is even almost done, it may not provide enough gas flow for the heat to be produced.
Solution
Lighting a gas burner on your stove is a quick solution to see if you have enough gas flow. Since your stove uses propane, it is a quick way to tell if you have propane coming to your RV. Since you want good gas flow, turn on the main burner and see if it is in full force with no issues. If you see the burner bright blue for about 10 seconds, you should have the proper pressure from your propane tank.
If you notice a weak and intermittent flame, the issue could be a low propane tank, gas valve, or gas leak. If your tank is still full, check to see if you have a gas leak. See if you smell propane outside. With bad gas flow and a full tank, that is usually a sign the pressure is being lost in the line from the tank to the appliance, such as a gas, furnace, or gas water heater.
If there is no leak and there is still a pressure loss from your gas supply, it could be the gas valve or regulator. This gas valve reduces the high pressure from a propane tank down to the required pressure of the RV water heater. Like any other RV component, there could be a failure in the valve, reducing the pressure too much. If all other signs are okay, the gas valve could need to be replaced.
Ignition Failure
If you are getting a good propane source for your RV, the next fix to dive into is checking for ignition failure. There are a couple of options to explore when looking at the water tank ignition. Most modern-day RV hot water tanks use an ignitor to spark a flame. In contrast, other models use a pilot light as their flame source. We will touch on both scenarios, so go ahead and skip to the one you have. If you are unsure which one you have, keep reading, and there will be a clue to find out which one you have.
Ignitor
Do you hear clicking when you turn on your hot water tank switch? If so, that is your ignitor making a spark to light propane. This flame from your ignitor will combust the propane in the burner tube, creating heat. This heat warms up the cold water and makes the hot water. If there is any delayed ignition or an ignition failure, the water heater will still try to fire up but will shut down.
Pilot Flame
If your water tank has a pilot flame, it works similarly to the ignitor, as it will burn propane in the burner tube. However, the difference is that you will not hear clicking and need to turn on the water tank gas valve and light the pilot light.
Solution
The most common issue in either type of flame is wind or debris in the burner tube. Is your RV water heater going out on a windy day? Even with your cover panel, the vents there can still let in enough wind to cause the ignitor or the pilot light to go out. If it’s windy, see if you can block the wind and see if that makes a difference in your water tanks staying lit.
Another common issue is debris in the burner tube. This can be from rodents that decide to make a small nest in this warm little space. Inspect your burner tube and clear out any debris that may affect the burning of fuel in the tube. If you see some debris, you can use an air compressor to blow it out.
Thermocouple
Another component that could be causing an issue is the thermocouple. The thermocouple, also known as a flame sensor, takes heat from the burner and converts it to a low-voltage electrical signal. That signal tells the water heater that the water temperature is rising and that all is functioning correctly. If the thermocouple does not signal heat, then the hot water heater thinks the fuel is not being burned properly and will shut off the fuel source, turning off the heater.
Solution
First, do a visual inspection and ensure no dirt or corrosion on the flame sensor. If you see any dirt, clean it off with water and a small cloth.
Next, test your thermocouple with a multimeter. Start by connecting one lead from the multimeter to each wire on the flame sensor. Set your multimeter to read volts, place the probes at either end of the thermocouple, and take note of the voltage readings. If there’s no voltage present, it could mean that your thermocouple needs replacing or repairing.
Final Thoughts
If your RV water heater fires up then goes out, it is likely a flame issue. First, start by checking your propane and fuel source. If all looks good there, check your ignition or pilot light for any trouble. Finally, check your thermocouple is clean and with a multimeter.
Tony is an avid camper and RV traveler. He fell in love with camping on his first RV trip with his wife over 25 years ago. Tony loves sharing lessons learned and tips about RV maintenance and safe traveling.