Common Mr. Heater Big Maxx Problems

The Mr Heater Big Maxx is a convection heater that can heat up to 1850 sq ft of space with its max setting. This unit can supply heat for up to 12 hours on one tank of gas, which is very convenient.

Unfortunately, this unit also comes with problems like many other appliances out there. So, what happens when you encounter some of its issues? This is a question we plan on answering in this post.

We’ll highlight some of the issues and how best you can fix them faster and efficiently.

Common Mr Heater Big Maxx Problems

Heater Big Maxx Won’t Stay Lit

One of the common Mr Heater Big Maxx problem you may have is when it’s struggling to stay lit. The issue might be that the diameter of the burner orifice is small,the gas pressure at the inlet is too low. The heaters have a built-in electric high velocity fan to pull cool air into the rear of the heater across a heat exchanger then force warm air into the surrounding areas. You can clean the heat exchanger by blowing out all the dust using compresssed air

To fix this issue, here is what you need to do:

  1. First, pull off the clear hose on the exhaust fan combustion chamber
  2. Use a 3/64 drill bit to poke and clear the hose
  3. You’ll most likely find that it was clogged with rusty debris
  4. Once you’ve cleared everything, it should be able to work now

If the following the above steps don’t solve the issue, consider pulling the same clear hose at the blower motor end. And then blow, suck, blow, and suck several times in the hose again. You’ll hear the pressure switch clicking while doing this. 

It will eventually loosen the pressure switch inside and make the heater work properly. If all the above fixes doesn’t work, no warm air will be pumped into the room and then the last option is replacing the pressure switch.

Heater Big Maxx Keeps Running

One thing that may be causing your heater to keep running may be a clogged, dirty air filter. If you have such a thing in your heater, it may not send enough heat into your home, thereby causing the heater to keep running. Therefore, the best way to fix this issue is to try and clean your air filter and replace it every two to three months.

Another issue may be that your thermostat is not set correctly. It may be that someone else might have cranked up the heat and caused the heater to keep running. Also, check that the thermostat is set to “heat,” The exhaust fan should be in the “auto” mode to ensure it functions properly.

Check the ductwork because it may be leaking. If it’s leaking, then the heat might be ending up in your attic instead of your house, causing the heating system of your heater to keep running. Search for leaks and seal them with HVAC tape.

Why Does My Mr. Heater Keep Shutting Off?

If you’re having issues with your Mr. Heater about shutting off constantly, it may be that the thermocouple is too far from the flame. This might cause the pilot to go out and shut down the heater. To fix this issue, move the thermocouple closer to the flame. The second reason may be that the thermocouple is worn out. If this is the case, you may need to replace it with a new one to prevent your Mr. Heater from shutting off constantly.

Heater Big Maxx Short Cycling

There are several reasons why your Mr. Heater Big Maxx may be short cycling. These include:

  • Theater might be too big
  • It is overheating
  • Or the thermostat is malfunctioning.

If your heater is too big, it may be causing uneven heat distribution resulting in short cycling. Therefore, you need to consider getting a suitable heater for the space you want to heat. If the issue is overheating, then this might be caused by restricted airflow.

Therefore, you need to contact a professional repair service to fix this issue. If malfunctioning is the one causing your heater to short cycle, it simply signals that the temperature in the room has been met. This may cause the heater to short cycle. 

Heater Big Maxx Circuit Board Problems

If your heater has circuit board problems, the issue might be either it has loose wiring, clogged filters, dirt, or the wrong fuse. After using the heater for a while, the wires might become loose due to the vibration. Therefore, this can cause a short and failure of the circuit board. 

To fix this issue, you need to contact a professional technician. 

If the issue is the clogged filter, consider cleaning it thoroughly to ensure you eliminate all the debris and dust. A faulty fuse that is too small for the heater or hasn’t been cleaned in a while could also cause circuit board problems. You can check whether this is the issue or hire a professional to check it for you.

Heater Big Maxx No LED Light

The indicator light on the control board is out of order. The first thing to do when this happens is to check all the batteries in the remote and replace them, if necessary, with new ones. If that does not solve your issue, you should move on to cleaning up any dirt or debris from around the gas valve switch (A). You can use a small screwdriver to remove metal particles and other foreign objects that may be blocking it from working properly.

If you have power to the gas valve an still there is’nt electronic ignition then maybe it’s on safety lockout.

Heater Big Maxx No Power

Some of the causes might be:

  • Bad wiring in the house
  • The breaker is bad and needs to be replaced
  • Faulty thermostat or other heating control board that’s shutting it off unexpectedly

To solve this issue, you need to ensure the power is on by testing it with a different appliance. Then, if another device works, you know your breaker needs to be replaced. If that doesn’t work, take a look at what might have caused the original problem and fix that up first before checking out each other’s components in the system. The last thing you want to do is end up replacing parts unnecessarily because of something simple like turning off one pressure switch or resetting one thermostat setting.

Heater Big Maxx System Lockout

The reason why your Mr. Heater Big Maxx System has lockout is that it detects a problem. Either the pilot is not lit, or there’s an issue with any of your gas functions. When this happens, you’ll need to take action and fix the cause of the lockout before turning it back on again. The first thing you should check is whether Mr. Heater Big Maxx system lockout occurs or whether your pilot light is working correctly. 

You can do this by lighting up the manual spark ignition switch. As well as shutting off all other valves for natural gas to flow through only one small hole near where your propane hose connects into. The next step would be going outside and checking if you have a clear blue flame coming from that single opening. This would mean that your pilot needs replacement work done immediately.

When the flame safety sensor does not detect flame because they are either dirty, you are having bad flame sensor, broken wire or bad control board.

Another reason your Mr. Heater Big Maxx System lockout may be occurring is that there’s an issue with one of the gas functions. This could mean that you either have a loose hose or broken pipe to deal with. You can check both by turning off all valves and looking at each part carefully for any signs of leakage, cracks, or corrosion.

Heater Big Maxx 3 Flashes

The first thing to check is that the power cord from your Mr. Heater Big Maxx runs into a GFCI outlet or has been recently replaced with one. If you have an older model, this might be a good time to upgrade and get on board with more safety features for yourself and any guests around while enjoying their stay in your cabin. 

First, ensure all settings are turned off before going through each step if it’s still flashing three times after checking these things out. It can also mean there isn’t enough oxygen getting to the pilot light. This means something may need replacing like blower fan blades on top of the grill or intake blower needed reinstalling properly, among other things. 

But again, only do anything beyond what I already listed if it’s flashing three times after checking all these things. Check the pilot light by using a flashlight and looking into the top of the heater where you’ll be able to see it with ease, making sure there is no debris blocking your view like cobwebs or insects, among other things that can block the vision of the pilot light. 

If it doesn’t come on even though you know for sure that the power cord is getting hot, then the next thing to check would be the safety pressure switch which will need to be replaced, most likely along with its bracket holding in place at the same time. That’s because they’re sold together as one unit usually but always double-check model numbers just in case before ordering replacement parts online. Hence, nothing gets mixed up during the order process!

Note: For model numbers located inside Mr. Heater Big Maxx grill, you’ll need to remove them for this process. 

If there is power getting through the safety switch and the blower fan blade assembly isn’t bad, then the next thing would be the gas line itself. This will require replacing, most likely again but first, try blowing on the intake blower (located under the unit near the side of the hose or pipe coming out from the front bottom) with an air compressor. 

Another reason why your Mr. Heater Big Maxx might flash three times within ten seconds after igniting the pilot light could be due to the lack of ventilation in the area where the heater is located. For instance, not having enough windows open even though the weather permits, among other things that can restrict airflow. Hence, causing this problem. So, check all these possibilities before concluding that the gas line itself or pilot light assembly is bad since they’re usually selling together as one unit. 

Heater Big Maxx 4 Flashes

If you are seeing four flashes, the heater is experiencing a critical error. This may indicate an issue with your power source or complete failure of the heating element.

Usually, this is caused by one of two problems;

  • If the heater has been drawing power but not heating, it is possible that the element has gone out or your thermostat does not work properly.
  • It may also mean that you need to replace your battery pack.

To fix this, you will need to check your power source.

Ensure that the battery pack is plugged in and turned on. 

Then, ensure there are no visible issues with the cord or plug from the heater to its power source, as well as any extension cords you may be using. If everything seems okay at this point, then turn off all power sources and let it sit overnight before trying again.Now, if you see five flashes instead of four, this means that either the thermostat has been tripped by overheating or an internal error has occurred. Which might indicate a faulty temperature sensor circuit board. 

This would require some troubleshooting to figure out which part of the heater is faulty. Either way, I recommend replacing your battery pack if it has been used for a long time or hasn’t worked well in the past because this will likely be cheaper than replacing another component. 

Heater Big Maxx 2 Flashes

According to What Gas Technology, there are several reasons that Mr. Heater Big Maxx gas heater might flash twice. One problem is an overheating unit, so check for this by leaving it off and unplugging it before checking any other issues. If there is no smell of propane or gasses coming out of the venting system outside, you can turn it on again, if necessary. 

But do not leave it unattended until you find a solution because turning something like this back on could cause another fire hazard in your home.  Mainly due to excess heat being produced inside without proper ventilation systems. Another reason one might see two flashes from their Mr. Heater Big Maxx heater is due to carbon monoxide buildup, a poisonous gas that is colorless and odorless. 

Carbon monoxide detectors are available for purchase right through Mr. Heater if you want to ensure your family’s safety, as well as the heater staying safe from overheating or any other problems.

Heater Big Maxx Slow Flash

If your Mr. Heater Big Maxx doesn’t ignite, it could be because the spark electrode is dirty or defective.  You can clean one with fine sandpaper and then try again to see if that resolved the issue.  If this doesn’t work, you may need to replace it entirely as part of a larger repair process.

Another reason for a slow flashlight is that your tank might be too cold. Once the Big Maxx detects a heating issue, it automatically reduces its output until the fuel line has warmed up enough to normalize again.

If you suspect this is happening, move your Mr. Heater out of any breezy areas and closer to an enclosed space where heated air can circulate better around the propane tank. The third reason why your Mr. Heater Big Maxx might be showing a slow flashlight is that the gas hose is loose. 

If you’ve recently moved your Big Maxx, check to ensure its hose isn’t kinked and tighten it if necessary. If this doesn’t resolve the issue, we suggest seeking help from an experienced technician.

Heater Big Maxx Fast Flash

One common problem with Mr. Heater Big Maxx is the fast flash error, which means you are getting low voltage to your unit. If this happens, adjust the power source where it’s plugged in or plug it into a different outlet until it stops flashing.

Another reason for this issue might be that the temperature is too hot in the room, which would cause it to shut off automatically. You can solve this by adjusting the thermostat or turning down your heat source. If this doesn’t seem to work, then there might be a bigger issue with what is causing these two problems combined, and you should contact Mr. Heater’s customer service for further help.

Alternatively, you could hire a professional technician

Heater Not Lighting

Some of the reasons why your Mr. Heater may not be lighting are that the pilot light is out, there isn’t enough oxygen in the area, or it could be a filter issue.

Here are some of the steps you need to take:

  1. First, unplug the heater and wait five minutes. If you still can’t get it to work after waiting.
  2. Then inspect the gas supply line for damage. It might be clogged or disconnected from your propane tank. This is a common problem that will cause your Mr. Heater Big Maxx not to light up. Ensure the gas supply is not shut off and gas is available to the heater.
  3. If everything looks fine, but you are still having trouble getting the heater started, make sure there isn’t any dirt in the spark generator by cleaning off any debris with a dry cloth before trying again.

After checking each of these things, if your Mr. Heater Big Maxx still won’t light up, it might be time to call a professional.


Overall, the Mr. Heater Big Maxx is an easy-to-use propane heater that will keep you warm and cozy at home, in the garage or workshop. Remember to follow all of the instructions provided with your unit so you can stay safe while heating your space.

I hope this post has helped you learn how to troubleshoot common problems of the Mr. Heater Big Maxx unit. If you happen to have any more questions or feedback regarding our post, feel free to reach out through email, and we’ll be happy to help.

1 thought on “Common Mr. Heater Big Maxx Problems”

  1. just installed a new bog max, boggles my mind that it will not turn on i tried all the steps listed, all i know is there is no LED light flashing at all, HELP

Comments are closed.