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

If your Mr buddy heater keeps shutting off, the reasons might be a dirty pilot, wrong draft positioning, dirty thermocouple, malfunctioning gas valve, clogged pilot orifice, broken flame sensor, and faulty electronic spark mechanism.

Below you will get the easiest and most effective solution to each of these problems. You will never have to face your Mr Heater won’t stay lit again. So, let’s get started…

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

To make your Mr Heater troubleshooting easy and simple, first, we will tell you why your Mr buddy heater keeps shutting off or not staying lit. And then we will provide you with simple solutions, step by step. Okay?  First, collect the following tools to fix your heater problems:

  • A screwdriver set
  • Wrench
  • Microfiber cloth
  • Detergent 
  • Soap water
  • Water hose
  • Scrubs

1. Dirty Pilot

The pilot keeps your heater ignited. If your heater pilot is dirty, the heater pilot light won’t light. So a dirty pilot can be the culprit behind Mr Heater not staying lit. Carbon, oil, spider web, and other types of debris build-up can be why the pilot light is not working. And as a result, turning off the heater as well.


Cleaning the pilot will bring your gas buddy heater back to life. Here’s how you should do it:

  • Turn off the heater 
  • Use a screwdriver to dislocate the pilot
  • Clear out the dirt and debris with a soft piece of cloth
  • Use a sponge and warm soapy water to clean the pilot thoroughly
  • Clean the pilot with clean water and wipe it with a soft piece of fabric
  • Let the pilot dry properly before installing it back in its place

Wait for a while after installing all the connections to the pilot. Then turn the heater on to see if the ignition is okay now.

2. Improper Draft Positioning

The draft allows air supply in the heater system. The heater works with the help of this air. But if there is too much airflow, then the heater will not stay lit. Excessive air will blow the fire out. This usually happens if the draft is not fixed correctly. Improper draft adjustment results in the circulation of too much air in the system.


There are a few things you can do to stop air from putting your Mr Heater off. Here they are,

  • Adjust the draft position
  • Place the heater in an environment where there is no heavy air circulation
  • Put up a barrier around the heater’s draft

Try doing any 1 of these 3 things to get your furnace back to working.

3. Dirty Thermocouple

A dirty thermocouple is another culprit behind your mr buddy heater keeps shutting off. The thermocouple signals the heater gas valve when to open and when to close. A dirty thermocouple will fail to do it. It will signal the gas valve to close when it is not needed. As a result, the gas supply will stop, and the heater won’t stay lit anymore.


Cleaning the Mr Heater thermocouple is the best option in this case. Here’s how to clean the thermocouple for Mr heater:

  • Turn off the heater fuel supply
  • Remove the protective flame screen
  • Remove the thermocouple by unscrewing it
  • Rinse this thermocouple with cold and clean water
  • Wipe it gently with a soft piece of cloth
  • Place it in a dry place to let it dry for 30 minutes
  • Reattach it once it’s completely dry

Don’t try Mr Heater’s thermocouple bypass. It will only bring more trouble for you.

4. Faulty Gas Valve

The gas valve supplies the fuel in your heater. Your heater doesn’t work without this fuel. And this is precisely what happens when the gas valve is faulty. The gas valve can be broken, or it can be clogged. But whatever the reason may be, your heater won’t stay lit without a gas supply.


Replace the Mr Heater gas valve simply in the following method,

  • Turn off the gas supply
  • Locate the gas valve near the burner of the heater
  • Unscrew it from its place
  • Clean the area with a dry piece of cloth
  • Place a new gas valve in its place
  • Tightly screw the new gas valve 

Don’t be too rough while unscrewing and screwing the gas valve.

5. Dirty Pilot Orifice

The pilot orifice controls the flow of the gas to the pilot. You already know that if your buddy heater pilot won’t light, the heater will not stay lit. Again, if the pilot orifice is faulty, it will prevent the activity of the pilot. So basically a dirty pilot orifice will eventually cause the whole heater to shut down.


Cleaning the pilot orifice is very easy and highly effective. Here’s how to do it,

  • Turn off all the connections to the heater
  • Remove the burner shield to access the control knob
  • Gently pull the control knob to remove it
  • Remove the panel behind it to reach the gas valve assembly
  • Remove the bottom pilot cover to locate the pilot light assembly
  • Unscrew and remove the pilot assembly
  • Pull out all the gas lines from that location
  • Find the pilot orifice there
  • Apply compressed air through the opening till it looks clean

Now put everything back in its position and turn on the heater. It should work just fine.

6. Faulty Flame Sensor

The flame sensor signals the heater to function appropriately. It reads the atmosphere of the heater and sends commands to the heater system. The sensor will read wrong signs if it’s dirty. As a result, it will command the heater to turn off. This is the same as the heater not staying lit. 


Cleaning the dirty flame sensor is a piece of cake. You can do it this way,

  • Shut off the heater power
  • Locate the flame sensor
  • Unscrew the flame sensor from its place
  • Detach all the connections from the flame sensor
  • Use microfiber to delicately clean the flame sensor rod
  • Use the brush to clean the dirt and debris clogged in the flame sensor slot
  • Put the flame sensor back to its place and restore all the connection

This way, your flame sensor will send accurate signals to your heater system, and your Mr Heater will work the way you want.

7. Faulty Electronic Spark Mechanism

It’s very common for you to hear a clicking sound coming out of your heater. If the noise starts as soon as you turn the blower switch on, it can indicate a faulty electronic spark mechanism. You can ensure if this is the case by looking into the burner chamber. Visible electronic sparks will be noticeable there.


The solution to this is rerouting the wiring of the heater. You will find the electrical diagram of the heater in the user manual. This fix requires you to open up the heater system and re-install the wiring in accordance with the Mr Heater manual. This is a risky task. So it would be better to consult a professional.

And this is all you can do to make sure your Mr Heater always stays lit. Our suggestions are designed for your convenience. You will not have any difficulty if you follow our track.

Mr Heater Big Maxx 3 Flashes: What Does It Mean?

Mr Heater Big Maxx 3 flashes indicated the failed pressure switch. Now the question is, can a faulty pressure switch cause your Mr Heater to shut off? The answer is, yes.

The Heater pressure switch is a safety feature like the flame sensor. It identifies the condition of pressure in the furnace. Sometimes the draft inducer motor can create excessive negative pressure in the system. When this happens, the pressure switch signals the heater and shuts the whole device off. It does so to avoid damages the negative pressure can cause.

When you face this problem you can fix it easily by releasing the pressure. The problem usually lies in the vent, and pressure switch tube. You can clean both using a can of compressed air

Apply the air in the vent and use a brush to clear out as much dirt as possible. In case of the tube, detach it first. Then clear out the debris using the canned air. You may need to use a thin wire to clear out the stubborn dirt. If this doesn’t solve the issue, then your heater pressure switch is faulty. Here’s how you can replace it:

  • Turn off the heater power and disconnect the heater gas supply
  • Open the Mr Heater top cover panel
  • Disconnect the hose connected to the pressure switch and remove the wires
  • Unscrew the old pressure switch and remove it from its slot
  • Get a new pressure switch with the same pressure rate
  • Align the new pressure switch into its designated spot and tighten up the screws
  • Reconnect all the wiring and the gas connection

Now your pressure switch should work just fine. If it still doesn’t work then don’t waste a minute and call an expert right now.


Why pilot light won’t stay lit when i release the knob?

The pilot light won’t stay lit when you release the knob because the thermocouple has gone bad. You know the thermocouple is a safety feature. It stops the gas flow when it senses that the pilot light is gone. But when the thermocouple goes defective, it can’t function and so the pilot light keeps shutting off.  

Why propane heater shuts off after 5 minutes?

Your propane heater shuts off after 5 minutes due to a faulty thermostat, corded or defective flame sensor, pressure switch going to off position, and poor gas supply.

How do you know if you have a bad thermocouple?

If you want to know whether your thermocouple is good or bad, just press the gas supply switch for 30 seconds and see if the flame lights up, only to go out later. Flame going out means that the thermocouple is bad. 

How much is the heater repairing cost?

If you consult professionals to fix your propane heater, they will take about $300 to $1,500, depending on the problem.

Will a pilot stay lit with a bad thermocouple?

No, a pilot won’t stay lit with a bad thermocouple.

Why you should not try Mr heater thermocouple bypass?

Mr Heater thermocouple works to keep the heater safely working. Bypassing it can lead to heavy damage to your heater.

How much does a heater pilot light cost?

You can purchase a good pilot light from amazon for as little as $25.


Now you know why your Mr gas heater won’t stay lit and their solutions. So, whenever you find your Mr heater not staying lit, just follow our solution guide and fix it by yourself.

Besides, you know you can keep your Mr. Heater perfectly working just with proper maintenance. So, don’t forget to maintain your heater regularly. As a result, you will face fewer heater shutting off issues.

However, if you find yourself in any struggle with any other Mr heater problems, you can let us know in the comment box. We will come to you with the possible solutions ASAP.

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

    • Hi Milo

      The reasons might be a dirty pilot, wrong draft positioning, dirty thermocouple, malfunctioning gas valve, clogged pilot orifice, broken flame sensor, and faulty electronic spark mechanism.


  1. I am on my second Mr Heater Big Buddy, The first one I had nearly a month and it wouldn’t stay lit. Returned before 30 days and got 2nd one, same problem. I have an older model with a fan, which I have had about 7 years and never a problem. The new ones have a problem. Sometimes they work but more often will run 5 minutes and shut off.

    • Hi Laura

      Shocked to hear your 2nd one is also doing a problem. First, try to contact the dealer from whom you got it. If they don’t allow the return, then try to fix it according to our guide.


  2. my mr heater pilot will work and stay on but when i turn the knob to let ppropane in so it will heat up , the pilot goes out ! Do you have a solution ? Thank you

    • Hi Bob

      Check if the gas valve is loose or broken. And fix. Also, check if your heater venting is faulty and there is low gas pressure. I hope, you will get the solution.


  3. I’m curious I have a mr heater. The single can one. An I run it all day just fine. But I have tried to run it all night and it will turn off. Tried not using during the day an only at night but same thing. What could cause it to not run just all night??


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