How To Troubleshoot Mr Heater Big Maxx Problems [7+ Easy Solutions]

The most common Mr Heater Big Maxx problems experienced by users are- the pilot won’t ignite or won’t stay lit, the burner doesn’t ignite or ignition is delayed, whistling noise when the burner is lit, white residue, and burner backfiring during operation. 

However, read our today’s Mr. Heater Big Maxx troubleshooting guide and fix any of the above issues by yourself. 

All Mr Heater Big Maxx Problems [Easy Solutions]

We’ll now take a comprehensive look at the problems that we commonly see in Mr. heater and the possible causes behind each problem.

To solve the issue, you must first diagnose what is causing the problem and then perform the corresponding solution that we mention.

1. Pilot Won’t Light

When you turn your heater’s igniter knob and the pilot won’t light, there can be several causes behind it. You’ll need to figure out which one is the culprit in your case. Here are the possible reasons why your pilot won’t ignite.

  • The ignitor electrode is positioned incorrectly.
  • The ignitor electrode has failed.
  • There is no connection between the ignitor electrode and the ignitor.
  • The ignitor cable has been pinched or is moist.
  • The Ignitor cable is broken.
  • The Piezo ignitor is defective.

Check your ignitor electrode’s position, if it’s connected properly to the ignitor. Ensure that the ignitor cable isn’t moist, pinched, or broken. If you can find nothing in your inspection, it means your Piezo ignitor or your ignitor electrode has failed. You need to test the ignitor to pin down the source of the problem.

How To Test An Ignitor?

Here’s how you conduct an ignitor spark test to see if it’s working properly or not.

Step 1:  Turn off the heater.

Step 2:  In the burner junction box, disconnect the ignitor wires.

Step 3:  Release the screws or clips that are holding the ignitor in place.

Step 4:  Open the ignitor plate completely.

Step 5:  Bend the copper ignitor clips to a distance of 5/8″ to 34″ between the clip ends.

Step 6:  Connect the ignitor leads in the burner junction box to a test power cable with a switch.

Step 7:  To power the ignitor, turn on the test power cord switch.

Step 8:  Examine the ignitor clip ends for spark.

Step 9:  If a spark happens, move on to the secondary coil test.

Step 10: If the spark does not leap the gap or jumps only sometimes, the ignitor is malfunctioning and needs to be replaced.

Step 11: Turn off the ignitor’s electricity.


Now that you have pinned down the problem, you’ll need to perform any one of these fixes.

  • Change the electrode’s position.
  • Replace the electrode.
  • Reattach the ignitor cord.
  • If the ignitor cable is squeezed by any metal or tubing, it must be freed. Keep the ignitor cord dry at all times.
  • Change the ignitor cable.
  • Replace the control valve (for 10K units, the piezo is part of the control valve).

2. Pilot Won’t Stay Lit

Your pilot light may go out as soon as you let go of the control knob. Your heater won’t work and no warm air will be pumped into the room. It is best to solve this issue as early as possible. Here are some of the reasons that can be causing your pilot light to go out.

  • The gas supply has been switched off or the equipment shutoff valve has been closed.
  • Air in gas line during installation.
  • The ODS/pilot system is obstructed.
  • The gas regulator is not set correctly.
  • The control knob is not set to the pilot position.


Depending on the cause behind your pilot light not staying lit, these are the possible solutions.

  • Open the equipment shutdown valve or turn on the gas supply.
  • Keep the control knob pressed in. Repeat the ignition process until all of the air has been evacuated.
  • Maintain a clean ODS/pilot.
  • Change the gas regulator.
  • Set the control knob to pilot mode.

Read Also how to fix a water heater pilot light that not staying lit.

3. Burner Doesn’t Ignite

Generally, when the heater is in the ON position and the pilot is lit, the thermocouple senses the pilot flame, and gas is released at the burners to start ignition.

But one of the problems that Mr. Big Maxx heater users might face is that, after the pilot is lit, the burner doesn’t ignite as it should. The possible reasons that can be behind your burners not igniting are-

  • The orifice of the burner is clogged
  • The diameter of the burner orifice is too small
  • The gas pressure at the inlet is too low.


We’ll tell you what to do in short. But for an in-depth look, read our guide on how to troubleshoot a Mr heater that isn’t igniting or staying lit. But, here’s a quick look at how to solve this issue.

  • Clean or replace the burner orifice. Check your owner’s manual to know the proper procedure.
  • Replace the orifice on the burner.
  • Make contact with a local gas business.

4. Delayed Ignition

Delayed ignition puts you in a very risky position. As gas will keep building up till the burners ignite resulting in explosions.

You’ll most likely hear booming noises if your heater has this problem. Take a look at what might be causing this problem-

  • The pressure in the manifold is too low.
  • The orifice of the burner is clogged.

Whatever is causing this problem should be diagnosed quickly. Call in a professional if you’re not sure how to go about fixing it.


To fix delayed ignition ASAP, you can try to-

  • Call your gas utility company. 
  • Clean or replace burner orifice.

Also Read how to fix water heater delayed ignition.

5. Whistling Noise When Burner Is Lit

If you hear a whistling sound every time your burner is lit, there can be some issue behind it. Let’s take a look at the possible causes.

  • When the burner is cold, turn the control knob to the HI position.
  • There is air in the gas line.
  • The heater’s air channels are clogged.
  • A partially clogged or dirty burner orifice.


Figure out which cause is behind the whistling sound with some inspection. After you’ve diagnosed the cause, depending on your diagnosis,  here’s what you need to do.

  • Set the control knob to LO and wait a minute for it to warm up.
  • Run the burner until all air is out of the pipe, then have the gas line checked by a local gas provider.
  • Keep minimum installation clearances in mind. Check your user’s manual for relevant info.
  • Clean or replace the burner orifice.

6. White Residue Found

White powder residue formation in the burner box or on nearby walls or furnishings is another common problem you see with heaters.

This happens because vapors from furniture polish, wax, carpet cleaners and other similar products turn into a white powder residue when heated. 


To solve this, when using furniture polish, wax, carpet cleaning, or similar materials, turn off the heater.

7. Burner Backfiring During Operation

You should treat this problem carefully. Fix this issue ASAP. Call in a licensed professional for help if you don’t have much experience with home appliances. Here are the possible causes behind this problem.

  • The aperture of the burner is clogged or damaged.
  • Burner has been damaged.
  • A faulty gas regulator.


To fix your heater and stop your burner from backfiring during operation, you should- 

Mr Heater Big Maxx 3 Flashes [Meaning + Solutions]

Mr Heater Big Maxx 3 flashes indicate 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. Then 0pen the heater top cover panel.
  • Disconnect the hose connected to the pressure switch and remove the wires. Now 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.


How much propane does a Mr heater use per hour?

The burn rate of a gallon of propane is roughly 100,000 BTUs (British Thermal Units) per hour. This means that if you operate your heater continuously (30,000 BTUs), you’ll use around 1/3 gallon of propane every hour. Your heater would use around 1 gallon per hour at 33,000 BTUs.

How long will a 20 lb propane tank run a heater?

In an outdoor gas heater, a regular 20-pound propane cylinder can last up to ten hours. 

Can you use a Mr heater inside?

While parabolic propane heaters are typically considered to be suitable only for outdoor usage, the Mr. Heater brand portable infrared heaters can be used indoors. The manufacturers expressly advertise this point.

Do you need ventilation when using a propane heater?

Yes, proper ventilation is necessary for your heater to operate normally. Your heater needs oxygen to combust and without it, the risk of producing carbon monoxide is increased. 

Can you use a Mr heater in a garage?

Absolutely. Mr. Heater is a portable garage heater that may be used in enclosed spaces like garages and workshops, as well as other locations like storage buildings, barns, sheds, construction sites, tents, and more. It is more effective indoors than outside, and it must be maintained away from flammable or combustible things.


Hopefully, our guide on the solutions to Mr Heater Big Maxx problems helps you out. If you have more questions, let us know in the comment. We love hearing from our readers. 

8 thoughts on “How To Troubleshoot Mr Heater Big Maxx Problems [7+ Easy Solutions]”

  1. My Mr. Heater Big Maxx is very noisy when it first comes on, (burner is running) until the flame goes out..why? and can I fix this or is this just the way it works?

    • Hi Norris

      The possible causes are:
      1. When the burner is cold, turn the control knob to the HI position.
      2. There is air in the gas line.
      3. The heater’s air channels are clogged.
      4. A partially clogged or dirty burner orifice.

      Check all these issues and fix them.


  2. Q – I have the 80000 btu garage heater the upper burner tip where the flame sensor is will not light , the unit has good supply and drop across gas valve . The flame roll up from the burner tip below does not seem to be catching the upper one .

    • Hi Don

      Try cleaning the flame sensor. It might be dirty. If cleaning doesn’t work, then contact a technician. You may need to replace the flame sensor.


  3. I have 2 of the 80000 BTU units, the fans for each unit never turns off. When I push the reset button for the roll out switch the units will fire up. Once the heat reaches the temperature in the garage the burners shut down but the fans contue to run and the units will not fire back up without resetting them.

  4. I got a new mr Heater 50,0000 everything is new . The problem is it won’t shut off. I got it set to the lowest temperature I can.

    • Hi David

      To fix your Mr. Heater won’t shut off issue, it would be wise to contact the Mr. Heater customer support center or your local Mr. Heater dealer.

      Wish you all the best!


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