Mr Heater Big Maxx Reset Button [Location & How To Reset]

Beyond any doubt, as a garage or workshop heater, Mr. Heater Big Maxx is a popular choice for providing warmth and comfort on chilly days. But occasionally, it can experience several problems, like overheating or internal issues, that cause it to trip and stop working. In such instances, resetting the unit often resolves the issue.

But where exactly is the Mr. Heater Big Maxx reset button, and how do you use it to reset your big Maxx?

Mr. Heater Big Maxx garage heater utilizes hi-limit or roll-out switches on the top of the burner box as its reset mechanism. You can simply reset your heater by pressing both buttons.

From my long years of hands-on experience, I can assure you that resetting the heater is the easiest job that you can do by yourself. Read through our article till the end and explore all the effective processes!

Table of Contents

Mr. Heater Big Maxx Reset Button- Where Is It?

Before heading to the detailed resetting procedures, first, let’s track down the reset button location on your Mr. Heater Big Maxx.

Well, Mr. Heater Big Maxx natural gas unit equips flame roll-out switches that are mainly considered the reset button in this heater. The rollout switches are designed to be manually reset to set the unit to factory default settings. It has a red button on top that pops out when it trips. Pressing this red button will reset the unit and help turn your heater back on.

Mr Heater Big Maxx Reset Button

However, a tripped flame-out switch signals a serious problem running through the unit. For instance, the user needs to address the specific issue causing the rollout switch to trip.

Attempting to reset the switch without solving the underlying problem may temporarily restore operation but may lead to the recurrence of the safety issue.

What is The Flame Roll Out Switch in Mr Heater Big Maxx? What’s The Purpose of it?

The flame rollout switch is a safety component in Mr. Heater that is designed to shut off the heater when the temperature exceeds a certain level. The switches are essential for safety functions as they prevent damage to the heater as well as severe fire hazards in your house.

You will find the switch on the top of the burner box, just behind the ignition control board. In general, it looks like a little metal circle with two wires connected to it. In the middle, there is a red button that is designed to be manually pressed to reset the heater.

Mr Heater Big Maxx Reset manual Button

Now let’s light the facts: how does it work?

Mainly, when the heater overheats, the flame rollout switch trips and cuts off the power and gas supply to the unit. Once the rollout switch has been tripped, the heater won’t respond to the signal from the thermostat calling for heat. Plus, you may also encounter four flashes of an error code blinking on your ignition control board.

How To Reset Mr. Heater Big Maxx [Step-by-Step Guide]

When you’ve determined the reset button location in your Mr. Heater Big Maxx, it’s time to explore the effective procedures to reset the heater. Here’s all you need to know about it:

Step #1: Safety First

As for the first step, you will need to ensure your safety before attempting to perform any service or maintenance on your heater. So, start by turning off the electrical power supply to the unit.  Turn off the power supply to the unit and unplug the appliance from the power connection.

It will be best if you turn off the power supply from the circuit breaker in your main electrical service panel. 

When it is done, turn off the gas to your heater. There will be a manual gas shut-off valve located nearby the heater, looking like a metal pipe with a knob or handle on it. 

Anyway, just turn the knob ¼ turn one way to shut off the gas. Or turn the handle perpendicular to the gas line, meaning the valve is closed. 

Step 2: Remove the Panel

Now it’s time to remove the front panel of your heater to look inside the box. There are often 4 removable screws holding the cover panel in place. Remove the screws from the top and lower of the panel and take the cover off. 

Now you will be able to see the burner assembly where the reset button or flame rollout switch is located. 

Step #3: Locate The Rollout Switches

In this step, locate the rollout switch located on the burner box top. We have already highlighted a picture of what the switch looks like. If you are still confused, you can see the diagram below:

Mr Heater Big Maxx Reset Button diagram

Anyway, check for more than one switch there. Typically, there will be a small button in the center, protruding outward. Also, be careful not to harm the two wires connected to each of them.

Step #4: Press The Button Between Two Leads

Before heading to touch the heater inside, make sure your heater has fully cooled down. If so, press the small button inward firmly to reset your heater. You will hear or feel a “click,” signifying it has been reset.

If it becomes successful, this will allow the gas to flow to the unit and the burners to fire again when the next heat cycle begins.

Note: If you press the button but it doesn’t click, don’t worry, it means that the switch is not tripped. Figure out other troubleshooting options in your Mr heater Big Maxx

Step #5: Turn the Gas and Power Back On

At this stage, when everything is done, set the cover panel back in. Then restore power and gas supplies to your unit.

Step #6: Consider Resetting the Flame Rollout Switch One or Two Times

Once the heater is powered back on, monitor its operation closely. In case it trips again, do not keep resetting the switch. Rather, the best practice is to turn off the power and gas to the unit.

The switch keeps tripping, and turning off the power supply to your heater means there is a serious problem in your unit. It’s an indication of a safety concern that requires professional attention.

Continuing to operate the heater without addressing the root cause can pose significant risks. Thus, it’s better to call a local HVAC company to track down the actual problem and corresponding solutions in your Mr. Heater Big Maxx.

Common Reasons Why Your Mr Heater Big Maxx Reset Button Keeps Resetting?

The flame rollout switch is a safety device in your heater that is designed to protect against potentially dangerous conditions. Tripping this switch indicates a serious problem within the heating system.

You reset the switch, okay, but the problem starts when it keeps tripping. That’s the point where you will need to understand the underlying issues causing this continuous tripping of the reset button or roll-out switch.

Anyway, here are some of the possible reasons to include causing the flame rollout switch to trip that need to be addressed:

1. Blocked Venting 

The first factor that causes the rollout switch to trip is the temperature rise. For instance, a higher possibility is that the venting system of your heater is clogged with dirt and soot buildup.

Gas-fired garage heaters burn fuel to produce heat. During combustion, the heating system produces byproducts such as carbon monoxide that need to be exhausted. Exhaust venting helps to maintain good indoor air quality by exhausting combustion byproducts and ensuring a steady supply of oxygen for combustion.

Over time, the accumulation of debris, dust, or other materials in the exhaust vent blocks the flow of combustion byproducts, leading to incomplete combustion and overheating of the unit. This causes the flame roll-out switch to trip randomly.

How To Fix:

First off, make sure you have turned off the electric and gas supplies to your unit. Now inspect your venting for the buildup of soot, bird’s nests, or tree branches and leaves.

Use a vacuum cleaner (shop vacuum if available) and clean out the dust, dirt, pet hair, and other debris stuck in the heater venting. It would be best if you could use a vacuum cleaner with a brush attachment on the end of it. It will help you a lot to clean the irregular surfaces.

Once the major stuff is cleaned, use a damp cloth to clean out the outer surfaces of the vents.

2. Low Gas Pressure

Low fuel pressure is another major reason to blame for the continuous tripping of the flame roll-out switch. Basically, when the gas pressure in your unit is too low, the flames don’t have enough force to be properly drawn into the heat exchanger, where they should be burning efficiently.

Plus, low gas pressure can also lead to incomplete combustion, where not all of the fuel is fully burned.

This incomplete combustion releases unburned gas and carbon monoxide into the furnace, which can cause the temperature inside the unit to rise and trip the safety switch.

How To Fix:

First, check for proper gas pressure entering the heater. A minimum of 5.0” w.c. for natural gas or 10.9” w.c. LP/propane gas should be maintained for proper unit operation. If needed, adjust the gas pressure by using the pressure regulator.

In most cases, low gas pressure in a heater is caused by dirty burners. When the burner orifice becomes clogged by soot buildup, it is obvious the gas pressure will drop. 

For instance, use compressed air and a wire brush to clean the burners and the orifices.

3. Blocked Heat Exchanger

The heat exchanger is the part of the heater that transfers heat from the combustion chamber to the air.

Mr Heater Big Maxx heat exchanger

Over time, dirt, dust, and debris can accumulate on the heat exchanger surfaces, which reduces the heat transfer efficiency of the element and overheats the unit.

Even corrosion is a common case of metal heat exchangers. Corrosion byproducts create a layer of material that can clog the exchanger.

Plus, the clogged heat exchanger disrupts the combustion process, which allows the flames to roll out and trip the roll switch.

Whatever the fact is, a thorough cleaning of the heat exchanger will be enough to get it back into normal operation.

How To Clean Heat Exchanger?

Before proceeding, turn off the power supply to the heater at the breaker panel. Also, disconnect the gas line using a wrench.

When done, gather some essential tools for the cleaning process. Like:

    • A soft brush

    • A vacuum cleaner

    • A mild detergent solution

    • Protective gloves and eyewear for your protection.

Now, remove the coverall panel from your heater and locate the heat exchanger from inside. If you are uncertain about the location, refer to your heater’s manual for specific instructions on accessing the heat exchanger.

At this point, use a vacuum cleaner and remove any loose dust, dirt, or debris from the heat exchanger’s exterior. Now, take a soft brush and dip it in the mild detergent solution.

Then scrub the exterior surfaces of the heat exchanger and remove any remaining dirt or grime. When done, wipe down the surfaces with a clean cloth.

To clean the interior tubes of the heat exchanger, use a long-handled brush or pipe cleaner and carefully remove any soot or debris buildup from the interior surfaces.

After thorough cleaning, reassemble all the components back in place and ensure a snug connection for all that. Restore the power and gas supply to the unit and check for proper operation of the heater.

4. Cracked Heat Exchanger

Besides blockage in the heat exchanger, another major sign of a tripped flame-out switch is a cracked heat exchanger. Yes, you got it right!

After long use, it is not uncommon that your heater heat exchanger will crack. A cracked or damaged heat exchanger allows combustion gases to infiltrate the air back into the heater and your home.

If that is so, it is quite dangerous for you, as the carbon monoxide from the combustion gases is extremely toxic.

How To Fix:

When you are certain that the heat exchanger of your heater is cracked, do not attempt to repair it by yourself. Call a licensed and qualified HVAC technician immediately to perform necessary repairs or replacements.

5. Broken Roll Out Switch Itself 

Last but not least, a broken flame rollout switch is the culprit if it is tripping again and again. The switch is mainly designed to shut off the heater if it detects a dangerous condition, such as excessive heat or flames rolling out of the burner. A broken switch may not be able to detect these conditions properly.

Mr Heater Big Maxx flame rollout switch

How To Fix:

If you suspect a broken rollout switch, it is important to have your rollout switch checked as soon as possible. Call a professional in this instance, they will better suggest to you whether it needs repair or replacement.

How To Test The  Flame Rollout Switch In Your Garage Heater?

Manufacture recommends manually testing the roll-out switch in your Mr. Heater Big if it keeps tripping or is not working as it should.

In the normal state, a flame rollout switch is closed, which means the electrical circuit within the switch is complete. But when it detects abnormal conditions in the unit, it trips or opens the electrical circuit. In most cases, the switch has gone bad at all, with a high-resistance circuit running through it.

Anyway, here are the simple steps to test the roll-out switch of your heater to confirm its defect:

Step #1: Start by turning off the power supply to your heater. Also, turn off the gas supply from the main gas shut-off valves.

Step #2: Disconnect the front cover panel of your heater and get access to the burner compartment. Locate the roll-out switches on the burner top.

Step #3: Now, press the rollout switch by pressing the button on it. Then disconnect the connected wires from the flame rollout switch terminals.

big maxx flame rollout switch terminals

Step #4: In this step, take your multimeter and set it to the ohms (Ω) setting. Connect the multimeter probes to each terminal of the switch.

testing rollout switch with multimeter

Step #5: If the multimeter shows a very low resistance within (0, 1, or 2Ω), then don’t worry. Your flame rollout switch is in good working condition.

Step #6: If the switch is open, the multi-meter will show a higher resistance reading.

Step #7: After testing the switch, it’s time to reassemble everything back together. Make sure there is a snug wiring connection to your flame rollout switch.

In case the switch is bad, you’ll want to remove the defective part and replace it with a new one.

 Is It Safe to Just Reset Flame Rollout Switch?

No, it is not safe to just reset the flame roll switch of your heater without addressing the underlying cause of the trip.

As already mentioned, a flame rollout switch is a safety device designed to turn off the unit if it detects a dangerous condition. For instance, it trips, telling the user that there is a problem with the furnace that needs to be addressed.

If you are just resetting the switch without addressing the root cause of the problem, it could allow severe and dangerous conditions to persist. For example:

#1. Fire hazard: If the flame of the heater burners is rolling out continuously, there may be a risk that they could ignite nearby combustible materials.

#2. Carbon monoxide poisoning: If the heater is not venting properly, it means that the combustion byproducts, including carbon monoxide, are not effectively removed from the living space.

#3. Damage to the Heater: Resetting the tripped hi-limit or flame roll-out switch without investigating the corresponding reasons leads to severe damage to many sensitive parts of the heater.

Thus, it is important to treat a tripped flame rollout switch if you need to reset the switch again and again.

Can I DIY the Flame Rollout Switch Replacement in My Mr. Heater Big Maxx?

Yes, it is technically possible to replace a flame rollout switch on your own. But in general, it is not recommended that you attempt to replace a flame rollout switch by yourself unless you have significant experience in electrical work and heater repair.

The flame rollout switches are relatively inexpensive, ranging from $10 to $40, and they are easy to install. But still, if you are uncertain about the replacement process, it is best to call a qualified technician to complete this task for you.

This is crucial because the flame rollout switch is a safety device that plays an important role in preventing fires and carbon monoxide poisoning in the system. If you can’t ensure the proper installation of the switch, it could start malfunctioning and pose a serious safety hazard.

Can You Bypass the Flame Rollout Switch In Your Heater?

No, you should never bypass the flame rollout switch on your heater. It is a safety device that protects your system from several serious conditions. If you bypass the switch, you are disabling this important safety feature. 

That means your unit may continue to operate even if there is a dangerous condition present. This may cause fire hazards and extensive, irreparable damage to your heater. 


What is the 2 flash code on Mr. Heater Big Maxx?

The 2 flashing code on your Mr. Heater control board indicate a system lockout. This is an error message that indicates a failure of flame detection or a weak flame in the unit that won’t stay lit.

What causes a system lockout in my Mr. Heater Big Maxx garage heater?

The common reasons that cause system lockout in your heater include clogged or broken flame sensors, malfunctioning pilot assemblies, and air in the gas line. Plus, insufficient fuel supply or, at times, faulty thermocouples can also cause this issue.

How do I reset the system lockout in Mr. Heater?

To break the system lockout, move the thermostat from “HEAT” to “OFF.” Then turn the dial to “HEAT” again. Your heater will reset and will no longer be in lockout mode.

In Closing!

Here is everything you need to know about the Mr. Heater Big Maxx reset button and its usage. After thoroughly reading, I hope you will be able to locate the reset button easily and ensure the best usage of it.

But it is not safe to reset the button repeatedly, and the switches are tripping again and again. There may be another underlying issue that needs to be addressed.

We have already well-described the potential reasons behind this issue in our guide, highlighting the corresponding solution procedures.

Well, that’s all from us today! To learn more about this appliance, you can check out another guide on the Mr. Heater Big Maxx system lockout!

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 .

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