How To Fix Atwood Furnace Ignition Lockout Fault [3 Easy Ways]

Many of us experience the Atwood furnace ignition lockout fault which we can’t fix. Why? There are many reasons which you should ponder upon. Let us tell you one.

Suppose you didn’t clear up the inside debris for a long while. When you get to see the furnace is locked out, then you open up things and remove the sail switch, also make sure to clear up the spider web on it.

atwood furnace ignition lockout fault

Once done, you hit the Atwood furnace reset switch and yes, it’s clicked and lit. But, if it doesn’t work, what should you do? Don’t worry. 

Aside from the above trick, there are so many more. Only you need to know what the heck with the fault, right? Because different problems will take you to different methods to the heater problem solutions.

In this article, we will sort out how to fix a furnace ignition lockout fault. So let’s delve in…..

What Is An Ignition Lockout Fault?

The fault goes to the pilot mode of ignition sensors. There are a number of sensors on your furnace. Each sensor detects a specific condition of your furnace.

When things come up with hazards, it can also detect and immediately keep the furnace shutting down. 

Well, this is what we called ignition lockout fault so this stand-still situation will only resolve when you want to revive the system then think about the furnace reset switch. 

Many of us have tried to reset it but fall short immediately because still, the sensors detect an unsafe condition. 

Types Of Ignition Lockout

There are two types of Atwood furnace lockout fault codes:

  1. Soft lockout
  2. Hard lockout

1. Soft Lockout

Most of the time we are unable to start the ignition due to two reasons, either it would be a defective flame sensor or a defective ignitor. 

The first few attempts to start during such conditions, the sensor won’t allow us to activate, turns out the controller limits us for a number of trials, which we called a soft lockout. 

This soft lockout is for the three consecutive times of trials afterward, it will go with the hard one. 

Meanwhile, if you can keep the furnace safe to run, then the sensor will automatically understand and allow you for a fresh start-up. 

2. Hard Lockout

Once you attempt to unlock the system several times without paying any heed to solve the fault manually, then the system will take you to the hard lockout which is known as lockout due to retries.

In this circumstance, you will need to go with resetting the whole system and fix the ignition lockout due to retries. The manual resetting of the unit only can save you which is not that rosy. Hence, you may need to call up HVAC technicians. 

How To Deal With Furnace Lockout?

You have already come to know about the soft and hard lock-out. Here is the important thing to consider upon the repetitive unlocking process. That being said, you should never try more than two times for unlocking it. 

Because it will lead you to the hard lockout settings and then you can never fix it alone without calling up the technician’s team. So, we recommend you to ensure the following things primarily: 

  • You tried to resolve the problem then unlock the system and you are successful to do so.
  • The problem still remains and you didn’t try to go with the unlocking process, then contact technicians.
  • You must come to know the problem is related to only lockout faults, not any other faults.

What Issues Cause The Lockout Of Your Furnace?

There are 3 probable causes of Atwood furnace lockout fault codes. Let’s now know in detail about them that will help you to fix your furnace lockout issue:

1. Defective Flame Sensors

While dealing with the furnace lockout, the first thing you need to peep and see- whether the Atwood furnace flame sensor is defective or not. Since it is the most common issue that drives you to the lockout fault, you should check this out first. 

Thankfully, one can resolve such an issue very easily without calling up experts. 

While checking, here you will get to see the furnace will keep shutting down even though you will start it and it begins to run for a moment. In such a case, you should have a new atwood furnace flame sensor and replace it immediately.

2. Faulty Igniter

After defective flame sensors, the most common issue is Atwood water heater not lighting . When you have encountered such a condition that time, the ignitor won’t respond, turns out the flame sensor fails to detect the presence of flames. 

As a result, the furnace will immediately shut down its entire system. In this case, you will need to have a quality atwood ignitor and replace it to resolve the issue.  

3. Limit Circuit Lockout

There are limitations with the rollout switch, when the switch remains on longer than 3 minutes then ignition lockout will occur. 

On the other hand, if the lockout will cross the limit with 10 successive attempts during the high or low heat of the furnace, then you will find the system will be heading to the auto-pilot mode for the lockout. 

How To Fix Atwood Furnace Ignition Lockout Fault [3 Easy Ways]

We found some of the tricks to fix ignition lockout on your furnace and they are explained below: 

1. Reset Your Atwood RV Furnace

The very first thing that you can do for fixing the ignition lockout fault is to reset your heater. You will find that Atwood furnace reset switch in the lockout mode varies from manufacturer to manufacturer. 

Most of the manufacturers use a simple reset button in the furnace. You will normally find the Atwood furnace reset button over the circuit board as you can see in the picture below.

atwood furnace reset button

The reset procedure involves switching out power to the furnace 30 seconds or longer and reversing it. The interrupted power supply helps toward the Atwood furnace ignition lockout fault fix and allows the machine to try again to run normally.

Now let’s know how to reset your domestic Atwood furnace: 

How Do I Reset My Domestic Furnace?

It’s super easy. Press the hold button ‘+’ then press the on/off button. LCD’s going to reveal. This method is known as Atwood furnace ignition lockout fault 3 flashes with a 3-second pause.

So, while pressing them, make sure you will hold both of these buttons at a time for 3 seconds. Then go back to the on/off button once again and this will reset your Dometic furnace. I hope, you will discover your furnace lockout issue is fixed.  

How Many Times Can I Hit the Reset Button On My Furnace?

It is not recommended to hit the reset button more than two times. Because it leads the oil into the burner chamber, and it will gather abruptly and cause an explosion. 

So, when you will see the first two attempts won’t work out, then call technicians. 

2. Clean or Replace the Sensors

After resetting the atwood furnace, you find the lockout issue is still. Now, what you should do?

You know, when dust, mites, and debris burgeon in great numbers, then your sensors would be susceptible to get damaged. So make sure, you will open things up and clear the system. 

atwood furnace flame sensor

On the other hand, your sensor might be choked to death due to smoke or sooted with the clog. Here clearing things up won’t fix it well, so you should rather change the sensors. 

  • First off, switch off the power of your furnace. 
  • close the valve and pull out the mounting screw.
  • Now, pull out all the sensors.
  • Carefully, inspect the furnace sensors whether it looks sooty, corroded, burnt or it only requires cleaning up.

It’s hoped you will discover the solution. 

3. Replace the Air Filter

If you come to see the air filter badly get clogged with dust, then you either need to clean it or replace it with a new one. The cleaning solution is the easiest and best solution ever. 

When you want to see a healthy unit of sensors, then you must clean the registers and vent regularly. Once you find over-clogged vents or register then, you won’t have a choice without replacing the air filter. 

We recommend you check out whether the furnace filter is unclogged or not. If you have recently changed the air filter and it gets clogged, then most probably just wiping it out would be okay. 

On the contrary, if you will keep it without cleaning for a long time, then it would be vulnerable. Turns out, you need to replace the furnace air filter.

Why Does My Boiler Keep Going To Lockout?

A boiler lock-out is a shut-down process that starts when there are certain tolerances in a boiler. This may be because of low/high water pressure, lack or no fuel supply (gas, LPG, or oil), system blockage, or electronic part power failure.

The Atwood furnace reset switch will go when you’ve gone out of fuel when you’ve got a gas or oil furnace. There was a mistake. 

If a furnace does not receive sufficient airflow, it will overheat and activate the reset button. Ensure that the air filters are cleaned or replaced with a new air filter and that there are sufficient air vents for proper airflow.

Hence it is very clear that you’ll come across the scenario of carrier ignition lockout fault. All you can do is, to ensure that no negligence comes from your side to avoid Atwood furnace ignition lockout fault for the maximum amount of time.

Here, you can watch the video to fix your Atwood RV furnace circuit board.


Where is the reset button on the furnace?

The motor reset button is a breeze while you want to turn off the power immediately. Well, it is right inside the circuit breaker. Here, you will open the blower compartment where you will find the blower motor and wheel. There try to find the small yellow button or red one (placed on the side of the blower motor). Finally, press the reset button, if needed. 

How do you fix the ignition lockout on a carrier furnace?

First off, you must comply that the lockout mode varies from one manufacturer to another. However, most of them use a common one which leads to turning the power off to the furnace for 30 seconds. Here, the uninterrupted power supply will solve carrier ignition lockout fault.

How long should a furnace ignitor last? 

It depends on the maintenance of your furnace ignitor. If you clean up the unit from time to time then it will last for 4 to 8 years. 

Final Words:

Atwood furnace is a superb choice because its sensible sensors keep you safe. But, when you face any Atwood furnace troubles, you may get frustrated. 

However, now you are free from this worry because we have sorted out the definite ways to fix the Atwood furnace ignition lockout fault with many other issues. You can easily solve the furnace lockout fault by yourself following our shown methods.

Yet, if you think, we left something uncovered, let us know, so we will come up with a solution for you. 

About William

William is the founder of He has real life practical skills in fixing smoker & heating appliance issues. He loves to share his knowledge & helps others in fixing their appliances & saving their money. William firmly believes that anyone can repair his or her unit with the correct guidance & knowledge. See more at about us.

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