Periodically examine burner flames for proper appearance during the heating season. Before each heating season, examine the burners for any deposits or blockage which may have occurred.
Clean burners as follows:
D-Combustion Air Inducer
A combustion air proving switch checks combustion air inducer operation before allowing heating sequence to continue. The sequence will not be allowed to continue if inducer is obstructed.
The combustion air inducer wheel should be checked and cleaned prior to the heating season. It should be examined periodically during the heating season to establish an ideal cleaning schedule. With power supply disconnected, the condition of the inducer wheel can be determined by removing the vent pipe and inspecting the wheel through the outlet opening.
Clean combustion air inducer as follows:
E-Flue Passageway and Flue Box
Source: MaintainX (Community Member)