Why Mr Heater Won’t Stay Lit [7 Easy Solutions]

The most common reasons behind your Mr heater won’t stay lit are the busted thermocouple, faulty pilot light, malfunctioning sensor, dirty pilot tube, clogged gas valve, defective spark mechanism, or a clogged pilot orifice.

mr heater won't stay lit

Cleaning and proper maintenance of your heater will keep it from automatically shutting off. Keep on reading this article to find out why your Mr heater keeps shutting off in detail. Let’s get started!

Table Of Contents

Why Mr Heater Won’t Stay Lit [7 Easy Fixes]

We’ll discuss the most common reasons why your Mr buddy heater keeps shutting off and provide you the solutions for each of those problems. This Mr heater troubleshooting guide will help you get your heater up and running again!

Note: You can also read the Dyna glo propane heater troubleshooting guide.

1. Busted Thermocouple

A thermocouple works as a safety mechanism to prevent gas leakage. It stops the heater from releasing gas into the environment.


The Mr heater thermocouple will become hot when the flame from the pilot reaches it.  This heat acts as a signal to the thermocouple to keep the gas valve open. 

A faulty thermocouple will fail to detect the heat and automatically shut off the gas valve. That’s the reason why your Mr Heater won’t stay lit.

Sometimes the Mr heater thermocouple can also move from its original position. It won’t be able to detect the heat if moves and it’ll shut off the heater.


The first solution is to check if your thermocouple is in its original position or not. You don’t have to replace it if it has changed its position.

Just move it back to where it was. If you’re unsure where it is, move the thermocouple one inch away from the pilot light.

There’s a good chance that the thermocouple is damaged if the Mr heater thermocouple adjustment didn’t work.

You should have to replace it. Your Mr Heater should be up and running again if a faulty thermocouple was the issue.

2. Faulty Pilot Light

The pilot light needs to be healthy for your heater to function well. There’s nothing wrong with your pilot light if it’s blue.

faulty pilot light

The blue flame of the pilot light ignites the gas to create the heating flame. The heater can’t maintain the temperature without enough pilot light.

Be on the lookout for an orange pilot light. It’s a sign that your pilot light has become weak.

Your pilot light becoming dirty or moving its position can also cause this problem. Air blockage can also be the reason why the pilot light won’t work properly.


Too much or too little wind will affect the health of the pilot light. Make sure its position hasn’t changed.

Try cleaning the pilot light with a cloth if it’s dirty. Take the heater to a well-ventilated place if you believe that a sufficient lack of airflow could be the problem.

3. Malfunctioning Sensors

Faulty sensors will also trouble your pilot light. There might be an issue with your propane sensor. This problem is generally caused by the build-up of dirt and debris on your sensors.

malfunctioning sensors

A malfunctioning sensor will automatically trigger the safety features and shut off your device.


The sensors will work fine if you clean them. Turn off your heater and use some sandpaper to fix the sensors.

Rub the sandpaper to remove the dirt that had built up on the sensors. Check that at least half or two-thirds of the sensor is covered by the flame.

4. Dirty Pilot Tube

The gas needs to pass from the thermocouple to the pilot tube for your heater to stay on. You’ll know if your pilot tube is dirty or not by looking at the color of the flame.

dirty pilot tube

Flickering or yellow flame is a good indicator that you have a dirty pilot tube on your hands.


Your first option is to try and clean it. Please make sure you turn off the gas first before you start to clean it. Gas is present in the pilot tube and it could cause an accident if you’re not careful. 

Turn off the gas and unscrew the pilot tube from the heater. The best way to clean it is to blow compressed air into the tube to remove any debris.

Use any sharp or pointy object to remove the dirt from the tube. Be gentle while doing this to make sure you don’t damage the tube.

Put the heater back together and turn on the gas. Your problem is solved if the heater works perfectly. You have to replace the tube if you can’t get the dirt out.

5. Clogged Or Faulty Glass Valve

Your heater runs on gas. The gas valve supplies this gas to your heater. Your heater won’t run without a functional glass valve.

faulty glass valve

Your glass valve can be damaged or clogged with the passage of time.


The glass valve is placed around the burner of your heater. Find it and try to clean it and the area around it. Replace the old gas valve with a new one if you’re unable to clean it.

6. Defective Spark Mechanism

Your Mr heater won’t run if the spark mechanism is defective. Turn off the gas to check the spark of your heater. You should see a spark when you turn it on.

defective spark mechanism

Another common sign of a faulty spark mechanism is that you’ll hear a clicking noise when your turn the blower on.


Refer to the user manual and find the electrical diagram of the heater. You’ll have to reroute the entire wiring system of the heater if this is the case.

Doing this is a complicated task. The recommended way to go about this is to get a technician to do it for you.

7. Clogged Pilot Orifice

The job of the pilot orifice is to control how much gas goes to the pilot. The pilot orifice can become clogged.

clogged pilot orifice

The pilot light won’t work if that happens and your heater will automatically shut down. Bugs or spiders can also get into the pilot orifice and end up clogging it.


You have to clean the pilot orifice. You can do this easily with a q-tip and alcohol. Add some alcohol to a Q-tip and put it about two inches into the area where the flame comes from the pilot. That should do the trick.

How To Light Mr Heater?

There are a lot of instructions in the manual to turn on the Mr heater. Most of them are safety precautions.

 how to light mr heater

We’ve broken it down into simple steps so that you light Mr heater easily:

  • Check the components of the device and make sure that everything is ready to be used.
  • Add a canister of 1lb propane which works with a valve connection
  • Place the heater and canister firmly.
  • Check for any leaks using soapy water.
  • Press the button for thirty seconds and the pilot light should turn on.
  • Release the button and the heater should light up.


Why does Mr heater require a thermocouple?

The thermocouple acts as a safety feature to prevent the propane gas from leaking into the air. It’s a highly necessary part of any heater as it prevents catastrophic accidents.

What is the most common reason why Mr heater stops working?

The build-up of dirt and debris is the most common reason why your Mr heater stops working. It needs regular cleaning and maintenance to work properly.

Is Mr heater’s thermocouple bypass a good choice?

No, it’s not. The safety mechanisms are in place for a reason. Bypassing it increases the chances of causing an accident.

Why is there a gas odor when running Mr heater?

There’s probably a gas leakage if you can smell the gas while your heater is running. Stop the device immediately, take it apart, and fix the possible leaks.


Now you know why your Mr heater won’t stay lit and how you can solve this problem. We’ve covered the most common reasons and appropriate solutions for this problem.

We hope you can finally stay warm and cozy with the comfort of a functional Mr heater. Let us know if this guide has helped you to get your Mr heater device running again. Leave a comment if you have any questions for us.

About David

David is a man who loves doing research and finding out the best solution to any type of heating appliance issues like heaters and fireplaces. Whenever he finds the perfect solutions to any issues of heating appliances after doing in-depth research, he loves to share them with his readers. In fact, his aim is to help his readers to fix the issues with their heating appliances easily.More about us .

7 thoughts on “Why Mr Heater Won’t Stay Lit [7 Easy Solutions]”

  1. There is a tip over sensor that can get stuck and the pilot won’t stay lit when trying to start it. Simple fix is to turn heater through vertical 360 degrees rotation and try to restart.

    • Hi Roger

      Clean the pilot assambly. Blowing compressed air into the pilot assambly is a good idea. After cleaning, wait for a few seconds then try to ignite.

      If it doesn’t work, contact the Mr. Heater customer support center.

      Best of luck!

  2. I have an issue with my 2 year old little buddy propane heater, the pilot will light and burn with a blue flame. I can turn it to either high or low and it will burn 3-5 minutes, then turn itself off with an audible click. After this, I can still light the pilot, however it will go out upon releasing the knob. I don’t know if there is a heated sensor to kick it off, or possible an oxygen sensor malfunction.

    • Hi Dewayne

      Clean the pilot light & thermocouple because if they get dirty, the heater won’t stay light.

      Plus, ensure the thermocouple is closer to the flame. Also, you need to replace the thermocouple if you get it faulty.

      Hopefully, your heater issue will be solved.

      Best of luck!

  3. I have MH12T ant the thermocouple mounting tab got bent, and was away from the flame; bent it back into position, and it worked fine.


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