Reznor 123974 Fan Switch Els PW 17895 Field Proven Durability: Standardized Johnson

Field Proven Durability: Standardized Johnson Controls pneumatic parts footprint for rapid retrofit or replacement

making it suitable for installation in VAV terminal units and air handling spaces without additional conduit in many jurisdictions

Always verify the part number against your existing burner assembly or service manual to ensure the rod length and mounting bracket align

In total darkness

including specific Reznor unit heaters

Reznor 123974 Fan Switch Els PW 17895 Field Proven Durability: Standardized JohnsonThe Reznor 123974 Fan Switch is a precise thermal control engineered for gas fired unit heaters and duct furnaces. Designed to manage blower cycles based on internal heat exchanger temperatures, this F135 30F fan control ensures the fan engages when the plenum reaches 135F and terminates operation once it cools to 105F (30F differential). As a direct replacement for part 48706, it maintains the critical timing required to prevent heat exchanger stress