Lennox furnace error code xp21
The Lennox XP21 error code can be a tough one to decipher. You may want to try resetting the error code as well as checking for air leaks or any other potential defects in the furnace or ductwork before you call a technician.
The Lennox XP21 error code is caused by a sensor that has been tripped and indicates that there is an issue with the equipment’s current level of operation.
The Lennox XP21 error code is a furnace control board fault error. It means that the control board is not able to communicate with the gas valve. This means that the furnace will not start.
Lennox furnace error code xp21 is one of the most common errors that you will come across with Lennox furnaces. While there are a good number of causes for this error, some of the most common ones are failing air filters, too much moisture around the heat exchanger, and dirt on the heat exchanger.
Lennox has developed a diagnostic tool to help troubleshoot this error code by identifying the type of problem in your furnace and then providing a solution to it.
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