What symptoms indicate this fan switch needs replacement

and Totaline models including HUMCCLBP

while the internal 1/2" bore secures to the round motor shaft using dual set screws

providing the consistent sparking and flame signal needed to engage the main gas valve without delayed ignition

Check the serial number on the rating plate

Browning 1VP65X 1 3/8 Sheave 321042-401 What symptoms indicate this fanThe Browning 1VP65X 1 3 8 is a heavy duty, cast iron variable pitch sheave designed for precise speed modulation in industrial and HVACR drive systems. This single groove VP sheave features a 6. 50" outside diameter and is engineered for high torque applications requiring a 1 3 8" finished bore with keyway. The adjustable pitch range of 4. 9" to 6. 4" allows technicians to fine tune fan speeds and blower performance on site, ensuring optimal CFM