Ignition Lockout Due To Retries [3 Easy Solutions]

It’s normal to freak out when your furnace shows error codes such as “ignition lockout due to retries”.

The most possible reasons for ignition lockout are the faulty or dirty flame sensor, defective ignitor or clogged ignitor due to dirt or debris, and finally obstructed air filters by dust.

ignition lockout due to retries

However, you can easily fix this error code just by cleaning or replacing the flame sensor, and cleaning the air filter including vent pipes. And to learn in detail and solve this lockout issue like a pro, go on reading the article…

What Does “Ignition Lockout Due To Retries” Mean

“Ignition lockout due to retries” is a common error code you see in most furnaces. But what is ignition lockout? What does ignition lockout mean?

Ignition lockout basically means the complete shut-off of the furnace’s power. This shut-off of power doesn’t occur without any reason. A furnace has certain types of sensors installed inside.

When any of these sensors identify any inconvenience or an unsafe condition, it sends a signal to the furnace controller. 

The furnace controller then shuts off the fuel and power supply to prevent any type of possible hazards. 

Different sensors detect different types of problems. But whatever the reason may be, the furnace will remain like that till it is reset.

When the system says “ ignition lockout due to retries”, it basically means that the switch response has exceeded its limit. When this happens, you can easily reset the whole system of your heater within minutes.

But wait!

Do not reset the system before solving the issue. If you just reset the furnace every time the ignition lockout occurs, you are not solving the issue. Here you are forcing your device to work despite its condition.

So what you have to do is, you have to solve the issue, and then you can reset the device. This way your device will remain healthy and usable for years. But first, let’s know the reasons behind such problems.

Is Ignition Lockout Due To Recycles Same As Ignition Lockout Due To Retries?

In terms of cause and solution, Ignition lockout due to recycles is the same as the lockout due to retries. The root cause for both is a dirty flame sensor.

Ignition lockout occurs when the flame sensor can’t detect any flame, and the ignitor keeps trying to spark a flame. This ignition retires can happen due to a dirty flame sensor.

By ‘ignition lockout due to recycle’ your furnace indicates the recycling of the ignition system. With time your furnace flame sensor attracts oxides. This dirt and debris prevent the sensor from identifying flame.

When the furnace can’t detect flame and keeps trying to restart the ignitor, the system eventually goes to lockout.

In conclusion, the origin and solution to both these issues are practically the same. Just keep following this article to get things back to normal.

3 Reasons That Cause Ignition Lockout Due To Retries

You are obviously here to know how to solve the issue of ignition lockout. But do you know what causes ignition lockout? 

If you don’t, then you should. Knowing what causes furnace ignition lockout can help you to deal with the issue like a professional.

It can improve your skills as well. This is why take a look at the possible causes of ignition lockout due to retries.

1. Defect In The Flame Sensor:

A defective flame sensor is a prominent reason for such lockouts. The purpose of this sensor is to detect flame once you start the furnace. 

However, if this sensor is somehow broken or dirty, it can’t properly identify the flame and send a false signal that will in turn stop the ignition sequence. 

2. Defective Ignitor:

If the ignitor does not get activated within seconds of turning your device on, the flame will identify this absence. And just like the previous point, the sensor will send a signal to turn off the device. 

This type of problem occurs when there is dirt or debris clogged in the ignitor. Such issues can result in massive destruction as well. Keeping the ignitor clean and free of blockage can prevent this problem.

3. Limit Switch Response:

Most of the furnace has a limit switch. Its purpose is to monitor the heat exchanger temperatures and the fuel pressure of the whole system.

The limit switch closes when the pressure gets too low or the temperature gets too high. This instructs the furnace control panel to shut the device off and eventually the furnace enters lockout mode.

Dirty air filters can cause the limit switch to trip as it reduces airflow in the system. These are the main reasons why ignition lockouts. 

And now that you know about it, it would be easy for you to deal with these problems if such a situation ever occurs. Here are the solutions that can fix your furnace’s ignition lockout in less than an hour.

“Ignition Lockout Due To Retries” Error Code [3 Easy Fixes]

May it be due to an internal malfunction or an external effect, no matter what caused your furnace to shut off needs to be dealt with immediately.

If you don’t take adequate measures not only can your furnace have permanent damage, it can result in devastating accidents as well.

In case you are wondering how to fix the ignition lockout on the furnace, here is the answer. Here take a look at the most effective solutions to furnace ignition lockout.

1. Clean The Flame Sensor:

You may need to replace or clean the flame sensor of your furnace. Closely inspect the furnace flame sensor to see if there are any kind of cracks or any signs of damage. 

In case you find cracks, call a professional immediately to fix the damage. 

However, it is possible that cracks are not the actual problems. It is accumulated dirt and debris that can cause such inconvenience.

If you notice that the flame sensor is dirty and collected a lot of debris around it then maintain the following method to clean it up,

  • Remove the 1/4 hex screw using a driver or a wrench.
  • Use steel wool, wire brush, or light grain sandpaper to rub off the dirt.
  • Use a dry paper towel to clean off the residue.

If cleaning doesn’t help either, replace the sensor. And then try to use the furnace. It should work now.

2. Clean The Air Filter:

You should clean the air filter on a regular basis before it is too late. A damaged or clogged air filter prevents airflow from entering the system. This, as a result, trips the limit switch, 

So, if this is the case, then the first thing you need to do is to clean the air filter. Here’s how you can effectively clean the air filter of your furnace,

  • Remove the air filter from the furnace
  • Use canned air to blow out all the dust
  • Rinse the dust off
  • Make sure that the air filter is totally dry before putting it back

If the damage is severe, then you will have to change the air filter of the furnace.

3. Clean The Vent Pipes:

Blockage in the vent pipes can result in shut off of your furnace. Such issues prevent the proper airflow in the system and as result, disturb the overall functionality of the device.

Though it’s usually easy to clean the vent pipes, you may find it hard. If the blockage is deeper inside of the vent pipe, you need to call a professional for help.

You may even have to replace the vent pipe as well. After you have gone through the 3 above-mentioned points, it’s time to reset the device.

No matter what the problem is, you always have to reset the furnace after making any sort of change. 

Resetting the furnace is fairly easy on most devices. You just have to turn off the power and wait for around 30 seconds before switching the power back on.

Many furnace models have such advanced sensors that they reset automatically 1 or 2 hours after the issue is solved. Follow the user manual for further details regarding this matter.

In case your furnace has a pilot light, you have to relight it following the instructions of the user manual. Each model has its own method. 

However, if neither of the above-discussed methods works, you will have to consult a professional. They will properly inspect your device and get it fixed. 

7 Other Common Error Codes

Apart from this particular error code that we have been discussing so far, there are many more error codes that indicate different issues with the furnace.

Knowing about these issues can help you maintain the device in a better way. Here are 7 most common error codes of furnaces.

1. Error Code: Rapid Red Flash

This error code means that there is a twinning error and the 24V phasing is incorrect.

Solution: Inspect the twinning wiring and see if the flame sense current is below 1.5 amp. 

2. Error Code: 1 Red Flash

This error code indicates that there was a flame but there was not a call for heat.

Solution: A leaking gas valve mainly causes this problem. So check the gas valve and make sure it’s in proper condition. 

3. Error Code: 2 Red Flashes

This error code means that the pressure switch contacts are somehow stuck in a closed position.

Solution: This mainly happens due to faulty pressure switches or faulty wiring. So rewiring should solve the issue. 

4. Error Code: 4 Red Flashes

This error code means that the main limit switch has somehow opened its contacts.

Solution: There are a few things that can be the reason for this issue. Dirty filler, incorrect blower speed setting, faulty duct system, faulty blower motor are the typical reasons for this issue.

So to solve this problem, you have to check the blower and duct motor and make sure that these two parts are perfectly fine.

5. Error Code: 5 Red Flashes

5 red flashes indicate that the contacts of the rollout switch have somehow opened.

Solution: Check for the combustion air and make sure that the inducer is operating properly. Reset the switch and the cycle power after making sure that the inducer is fine. 

6. Error Code: 6 Red Flashes

This error code means that the pressure switch somehow opened 4 times during the call for heat. 

Solution: See if the main blower is in “Delay on” mode. If it is, then turn off the device and restart it after an hour or so.

7. Error Code: 7 Red Flashes

The fault code of 7 red flashes means that the system has failed to establish a flame. 

Solution: The issues that cause this problem are faulty gas valves, faulty flame sensors, defective burner, and low gas pressure.

So make sure that that sensor, burner, and gas valve are okay. And that would be all. These are the 7 most common error codes that you may have to deal with your furnace.

If you are properly aware of these error codes and their solutions, you shouldn’t have any problem with the device.


What does ignition lockout due to retries mean?

A furnace has different types of sensors for different purposes. When any of this sensor detects any unsafe situation, the furnace controller shuts off the power of the device to prevent any kind of hazards. This process of shutting off is known as ignition lockout due to retries.

Why does furnace go into lockout?

A few factors can cause your furnace to go into lockout. The most common factors are,

  • Blockage in air filter
  • Dirty burner
  • Clogged vent pipe

How can the safety lockout be reset?

The simplest way of resetting the safety lockout is to set the thermostat below the room temperature.

Can you bypass flame sensor?

Unfortunately no, you cannot bypass the flame sensor of your furnace. Even if it were possible to bypass safety controls, you should never try to do so. What you can do instead is replacing or cleaning the flame sensor to get a better result.

How often should a flame sensor be replaced?

With proper care, the flame sensor of your furnace should last for 2 to 3 years. After this time period, you should change the part.

How much does it cost to replace the flame sensor?

When a flame sensor becomes too dirty or too old, it’s better to replace it. However, you can consider repairing the part as well. It will cost you anything between $80 to $250.

How do you know if a flame sensor is bad?

These are the 3 most apparent signs of a bad flame sensor,

1. The furnace lights only shut down after a few moments

2. There are cracks on the porcelain of the flame sensor

3. The flame sensor is corroded or sooty

How much does it cost to have a furnace ignitor replace?

A furnace ignitor replacement costs about $120. However, depending on your device, it can cost upto $225.


Ignition lockout due to retries is a serious problem for a furnace. But you can reduce the severity of this issue if you know the proper way of dealing with such situations.

If you utilize what you have learned from this article, then it shouldn’t be a problem for you to keep your furnace in a good condition. If you have any further queries, then do not hesitate to comment below.

About William

William is the founder of Fireplacehubs.com. 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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