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How do I troubleshoot my Lennox furnace?

Alton Alexander
By Alton AlexanderUpdated on June 4th, 2022

If your Lennox furnace is giving you an error code, there are a few things you can do to troubleshoot the problem. First, check the manual that came with your furnace to see if the error code is listed. If it is, follow the instructions for how to fix the problem. If the error code is not listed in the manual, you can try searching online for the error code and the model number of your furnace. This should give you some idea of what the problem is and how to fix it. If you still can't figure out the problem, you can contact a Lennox customer service representative for help.

Other common searches for this error include:

  • lennox error code list
  • lennox furnace troubleshooting

1. Check the furnace filter and replace it if necessary

  1. Check the furnace filter to see if it’s dirty or needs to be replaced. A dirty filter can cause problems with the furnace, including decreased heating and cooling efficiency, increased repair and maintenance costs, and higher energy bills.
  2. If the filter needs to be replaced, remove the old one and install the new one. Be sure to clean all the dust and debris from the filter before installing it.
  3. Reconnect the ducts and air registers, and test the furnace for proper operation.

2. Inspect the furnace blower belt and replace it if it is worn or damaged

To inspect the furnace blower belt and replace it if it is worn or damaged, first turn off the power to the furnace. Then, remove the cover on the furnace blower motor. If the belt is broken, worn, or torn, replace it. If the belt is not broken, worn, or torn, but needs to be replaced, follow these steps:

  1. Remove the screws that hold the belt in place.
  2. Remove the belt.
  3. Install a new belt.
  4. Replace the screws that hold the belt in place.

3. Lubricate the furnace blower motor with oil

  1. Verify that the blower motor is working by turning it on and off.
  2. Remove the blower motor cover.
  3. Lubricate the blower motor bearings with oil.
  4. Replace the blower motor cover.

4. Inspect the furnace igniter and replace it if it is defective

  1. Inspect the furnace igniter to determine if it is defective.
  2. If the igniter is defective, replace it with a new one.

5. Clean the furnace burners and adjust the air mixture to the proper setting

There are a few different steps that need to be taken in order to clean the burners and adjust the air mixture on a lennox furnace. The first step is to remove the cover on the furnace. Next, use a wire brush to clean the burners. Finally, adjust the air mixture using the dial on the furnace.

If you didn't find success with an option above, then try:

  1. Inspect the furnace flue for blockages and clear them if necessary.
  2. Call a furnace repair technician to inspect and repair the furnace.