RV Water Heater Fix: Lights Up Then Goes Out? Here’s Why

Experiencing the frustration of your RV water heater lighting up only to go out moments later? You’re not alone. This common problem can put a damper on your travel plans, leaving you without the comfort of hot water. In this article, we’ll explore the potential reasons behind this pesky issue and provide you with actionable solutions to get your water heater functioning properly again.

From troubleshooting the basics to diving into more complex fixes, you’ll discover how to tackle this problem head-on. Whether it’s a faulty thermocouple or a clogged burner tube, we’ve got you covered. Keep reading to learn how to ensure your next adventure isn’t left in the cold.

Common Causes of RV Water Heater Lights Going Out

When you’re dealing with your RV water heater lighting up and then going out shortly after, it’s crucial to understand the common causes behind this issue. Immediate extinguishing often points to specific malfunctions that can be identified and fixed with the right knowledge.

Faulty Thermocouple
A prevalent cause is a faulty thermocouple. This safety device detects whether your pilot light is on and, if not, it cuts off the gas to prevent leaks. If it’s malfunctioning:

  • Your heater might not stay lit
  • It might require replacement or cleaning

Dirty Burner Tube
The burner tube could be clogged with debris or insect nests, impeding the gas flow required to keep the flame alive. In this case:

  • Ensure regular cleaning
  • Inspect periodically for blockages

Air Flow Issues
Proper ventilation is essential for the flame to sustain itself. If there’s restricted airflow:

  • Check exhaust vents for blockages
  • Ensure there’s no damage to venting systems

Propane Gas Problems
Issues with your gas supply can also be a culprit:

  • Confirm gas valves are fully open
  • Check for adequate propane levels

Inspecting and addressing these areas are critical steps in solving the extinguishing flame issue. Familiarise yourself with your RV’s model-specific manual for additional guidance on these checks. This knowledge can save you time and maintain the comfort of your RV living conditions.

Troubleshooting the Basics

When you’re up against an RV water heater that lights and then goes out, there are a few basic troubleshooting steps to start with. Identify and rectify common issues before delving into more complex repairs.

First, check the gas flow to your heater. Ensure that your propane tanks are not only connected but also have sufficient fuel. A simple gauge check can save you time and hassle. Next, inspect the pilot light. If it’s weak or non-existent, there’s your culprit. Cleaning the pilot can often resolve this.

Assess the thermocouple, a safety device which detects whether the pilot light is lit. If it senses no flame, it will shut off the gas supply to prevent buildup. If faulty, it will need replacing.

Review the ventilation system for blockages. A blocked air intake or exhaust could cause the unit to malfunction. Clear away any obstructions that impede airflow. Additionally, evaluate the electrical connections if your model uses a spark igniter. Loose wires or corroded terminals could prevent proper ignition.

By systematically ruling out potential causes, you’ll corner the issue. Remember, regular cleaning and maintenance are your best defence against these common problems. If after these steps you’re still at a loss, it might be time to consult a professional.

Checking the Thermocouple

When your RV water heater lights up but then goes out, the thermocouple could be the culprit. To begin, locate the thermocouple; it’s usually situated near the pilot light. This safety device determines if the pilot light is lit and, if not, shuts off the gas to prevent a leak.

First, inspect the thermocouple to see if it’s dirty or bent. Any debris on the thermocouple can affect its function, so clean it gently with a piece of fine sandpaper or emery cloth. Straighten it if you find it bent, ensuring it’s positioned properly in the pilot flame, usually about 1/4 inch away.

Test the thermocouple by lighting the pilot. If it goes out quickly, the thermocouple may not be heating up sufficiently. You can use a multimeter to verify if the thermocouple is functional. Set it to millivolts and connect it to the thermocouple’s ends. A reading between 20 to 30 millivolts is typical when the thermocouple is heated.

If the voltage is low or nonexistent, it’s time to replace the thermocouple. This is a simple procedure:

  • Turn off the gas supply.
  • Remove the old thermocouple by loosening the connection nuts with a wrench.
  • Align the new thermocouple similarly to the old one.
  • Reconnect it to the control valve and pilot assembly.
  • Turn on the gas and test the pilot light.

Regular inspection of the thermocouple is vital to maintain an operative water heater. Make it part of your routine RV maintenance to prevent unanticipated issues during your travels. Ensure the area around the water heater is free of obstructions and that you have the right tools on hand for the job.

Cleaning the Burner Assembly and Tube

When your RV water heater lights up but soon goes out, a soiled burner assembly or tube might be hindering proper flame maintenance. Here’s how you address the issue.

First, turn off the gas supply to your heater to prevent any accidents. Ensure the unit is cool before you begin. Dismantling the burner assembly can seem intimidating, but with your manual in hand, it’s a straightforward process.

Once the assembly is accessible, inspect it for debris and insect nests, which are common culprits. You’ll want to use a soft brush or a vacuum with an attachment to gently remove any buildup. For the burner tube, a long, narrow brush works best to dislodge obstructions that can impede gas flow.

If you find corrosion, this indicates a more serious issue that might call for professional intervention. However, if it’s just dirt and debris, your cleaning efforts should significantly improve performance.

After cleaning, reassemble the parts carefully and turn the gas supply back on. Light the pilot and observe if the flame stays lit. Does the burner ignite now without issue? A clean burner assembly should produce a strong, steady flame, indicating it’s ready for another round of use.

Remember to regularly inspect and maintain these components to prevent future failures. Regular maintenance isn’t just a safety measure; it’s crucial for efficient operation.

Inspecting the Gas Supply

When your RV water heater lights then goes out, it’s crucial to check the gas supply. A consistent supply of gas is essential for the heater to function properly.

Ensure the Gas Is On

First, verify that your gas supply is turned on. The propane tank valve should be fully open to allow gas to flow to the heater. If it’s closed, your heater won’t stay lit.

Check for Propane Level

Additionally, check if there’s enough propane in your tank. A near-empty tank won’t provide adequate pressure for the burner to operate effectively.

  • Ensure the propane tank is at least one-quarter full
  • Consider using an inline pressure gauge for accurate readings

Inspect Gas Lines for Leaks

Leaks along the gas lines can disrupt the supply. Apply a soapy water solution to the connections and look for bubbles that indicate a leak. If a leak is present, tighten fittings or replace damaged parts.

Examine the Gas Regulator

The gas regulator controls the pressure of the gas reaching the heater. A malfunctioning regulator can cause an inconsistent flame that may extinguish itself.

  • Check for visible damage or wear
  • Clean any debris from the regulator vent

Gas Valve Operation

Finally, inspect the gas valve for proper operation. A faulty valve can impede gas flow, resulting in the burner going out after being lit.

  • Listen for clicks indicating the valve is opening and closing
  • Ensure there is no obstruction in the valve orifice

Regularly inspecting and maintaining the gas supply components will help keep your RV water heater running smoothly and prevent issues of the flame going out unexpectedly.


You’ve now got the knowledge to tackle the common issue of an RV water heater that lights up only to go out moments later. Remember, it’s often a matter of ensuring your gas supply is consistent and all components are functioning properly. Regular checks and maintenance can prevent this frustrating problem from recurring. Stay vigilant with your RV water heater and you’ll enjoy uninterrupted hot water on all your adventures. Safe travels and happy camping!