York S1-025-23280-000 Temp Control the 21L99 is the official

the 21L99 is the official Lennox replacement part for the older 21L9901 part number

allowing for direct hardwired connection to your controller's analog input without requiring additional conduit in many jurisdictions

Enhanced Reliability: Constructed with high-grade materials to withstand frequent thermal cycling in water heater pilot assemblies

Universal Compatibility: Fits most standard Imperial and aftermarket manifolds requiring a 1/8" MPT back mount connection

York S1-025-23280-000 Temp Control the 21L99 is the officialThe York S1 025 23280 000 is an OEM SPDT temperature control designed for precise thermal management in heavy duty HVACR applications. Engineered as a high reliability HVAC replacement part, this 0Op 15Cl thermal switch features fixed setpoints where the circuit opens at 0F and closes at 15F. As a Single Pole Double Throw device, it provides the versatile switching logic necessary for controlling defrost cycles, low ambient fan operation, or freeze