Trane Furnace Red Light Flashing 2 Times [Solved]

The Trane furnace red light flashing 2 times is an indication that your furnace has gone into hard lockout.

Now, there are quite a few reasons behind the furnace light blinking 2 times, including a faulty ignitor, improper air/gas mixture, and blocked airflow. 

trane furnace red light flashing 2 times

On top of that, loose wiring, malfunctioning pilot sensor, faulty control board, along with damaged heat exchanger also contribute to the issue.

However, the quick and instant way of fixing your Trane furnace red light blinking 2 times/hard lockout is to reset your furnace.

If resetting fails to bring your furnace to normal functioning, then you should find the culprit behind it.

And to find out those culprits and their solutions, go on reading our today’s ultimate solution guide. You will definitely get the solution. Plus, you will also learn how to reset your Trane furnace by yourself.  

Table Of Contents

Why Does The Trane Furnace Lockout Occur

Before going to explore the reasons behind the 2 bankings or hard lockout of your furnace, you should know why your furnace goes into hard lockout mode.

The lockout typically happens when the flame sensor in the furnace doesn’t detect the flame three times. 

When the furnace is turned on, the flame sensor detects a flame which ensures that the ignition sequence is functioning properly and the furnace is safe for use.

However, if the sensor fails to detect the flame within a certain period of time, it goes into a soft lockout and restarts the furnace operation. 

The furnace goes into a hard lockout if it fails to detect flame three times and blinks the red light 2 times telling you that your furnace has shut down as a safety precaution.

Then the furnace won’t function and start unless you reset the furnace or resolve the issue causing the lockout. 

How To Reset Your Trane Furnace To Fix Hard Lockout

Already you have known, resetting is the instant and primary solution to resolve the 2 blinkings or hard lockout on your furnace.

So, here are the simple steps to reset your Trane furnace:

  • Turn off the Trane furnace and unplug it from the power outlet. 
  • Let the temperature drop down completely before you start resetting the furnace. 
  • Find the reset button and reset the switch on the furnace. 
  • Press the reset button to stop all sorts of internal operations in the furnace. 
  • Once the furnace stops all operations, press on the reset switch for 30 seconds. 
  • Plug the furnace back in and turn it on to ensure that it’s working perfectly. 

In case the Trane furnace doesn’t work even after resetting, then the lockout is caused by an internal reason.

This means that the Trane furnace won’t turn on unless you identify and resolve the issue. And find out the issue, go on reading the next part of our guide.

Reasons For Trane Furnace Red Light Flashing 2 Times [Solved]

Here, we will discuss each and every possible cause behind the Trane furnace red light flashing 2 times. Let us dive deep into the reasons and their solutions. 

Note: You can also read how to fix the Atwood Furnace ignition lockout fault problem

1. Faulty Ignitor

The ignitor is one of the most essential parts of the Trane furnace. A faulty ignitor is one of the common reasons why the Trane furnace hard lockout occurs.

When the ignitor is damaged, it won’t light up a flame in the furnace. The sensor doesn’t detect a flame which causes the red light to blink 2 times. 


To fix the Trane furnace’s faulty ignitor, turn off the furnace and examine the ignitor properly and make sure that it’s in proper working condition.

Replace or repair the ignitor and turn the furnace back on to see if the Trane furnace operating properly. 

2. Improper Gas/Air Mixture

Trane furnaces use a certain amount of gas/air mixture in order to operate properly and heat up. Now, the furnace will not light up a flame if the gas/air mixture inside is incorrect.

The reasons why this happens are that the gas valve is faulty, the pressure isn’t correct, or the pipes are clogged. 


In order to solve the Trane furnace gas problems, follow these steps:

  • Examine the gas valve and make sure that it’s turned on. Repair or replace the valve if it’s faulty and turn the valve back on. 
  • Keep an eye on the pressure gauge and ensure that the pressure is accurate. Adjust the pressure to the correct setting and make sure that it doesn’t drop or rise. 
  • Turn off the furnace and clean the gas pipes properly. Set up a cleaning schedule and clean the pipes on a regular basis. 

3. Blocked Airflow

Improper airflow in the furnace is a common reason behind the Trane furnace flashing 2 times. The air pipes connected to the furnace often get blocked due to dirt, debris, and so on.

This accumulation of dirt in the pipes prevents a proper flow of air which in turn stops the flame. 


Turn off the furnace and check the air pipes properly. Clean all the pipes and remove all traces of dirt, debris, and other impurities.

Maintain a proper schedule for cleaning the pipes in order to prevent the problem in the future. 

4. Loose Wiring

Another common reason why the Trane furnace hard lockout occurs is loose wiring. The wiring connected to the sensor of the furnace often loses connectivity which prevents the sensor from detecting the flame.

As the sensor can’t detect the flame, it goes into lockout after three attempts. 


Turn off the furnace and examine the wires connected to the sensor. Make sure that all the wires are properly connected.

Take help from the Trane furnace manual and connect the wires in their proper position securely. Turn the furnace back on and check whether it is working properly or not. 

5. Malfunctioning Pilot Sensor

The pilot sensor has the responsibility of detecting the flame when the Trane furnace is turned on. The system goes into a hard lockout in case the pilot sensor fails to detect flame three times.

A malfunctioning pilot sensor often fails to detect the flame even when it’s there; thus, causing the red light to flash 2 times. 


Turn off the main connection to the Trane furnace and check the pilot sensor properly.

Repair or replace the damaged pilot sensor with a new one and ensure that it’s a proper fit. Turn on the furnace to make sure that it’s successfully detecting the flame. 

6. Faulty Control Board

The control board is an essential piece of the furnace that ensures the proper functionality of the Trane furnace. If the control board is faulty or damaged in any way, then it won’t be able to perform properly.

The control board often prevents the sensor from identifying the flame which results in a hard lockout. 


Turn off the furnace and open the control board. Check the keys and membrane properly to identify any damage.

Replace the faulty keys or the membrane with a new one and set it properly in place. Turn the furnace back on to check whether it’s working accurately or not. 

7. Cracked Heat Exchanger

Last but not least, a cracked heat exchanger often causes the Trane furnace red light to flash 2 times.

If the heat exchanger is cracked or damaged in any way, then it will trip off the sensor after a few minutes of operation. This means that the sensor will no longer detect a flame; thus, going into a hard lockout. 


Turn off the Trane furnace and let it cool down completely. Examine the heat exchanger and look for damage or cracks on the body that causes the sensor to trip off. Replace the heat exchanger and turn on the furnace. 


Is Resetting The Trane Furnace A Good Idea?

Resetting the Trane furnace will make it function like new if there are no internal issues. However, constantly having to reset the furnace indicates problems resulting in a hard lockout. 

How To Fix The Blinking Red Light On The Trane Furnace?

Find out the reason why the red light blinks and resolve the issue. Properly maintain and clean the furnace on a regular basis to make it operate smoothly. 


We have now reached the end of our guide. We hope that you now know all the possible reasons behind the Trane furnace red light flashing 2 times and how to solve them.

Whenever you encounter a hard lockout on your Trane furnace, take help from this guide and solve it on your own easily. 

If you have any queries or questions about the Trane furnace, let us know in the comment box below. We will get back to you with the best possible solution. 

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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