What is the difference between a relief valve and a safety valve in this context

Engineered as a genuine York OEM furnace part

The assembly features two distinct set points crucial for multi-stage heating: a low fire switch calibrated to -0

ensuring that scale and solder debris are trapped before they reach sensitive expansion devices

It serves as the direct replacement for Lennox 12J20 and 91M02

York S1-024-39718-000 Switch 30067439-890 What is the difference betweenThe York S1 024 39718 000 is an OEM two stage pressure switch designed for precision air flow monitoring in high efficiency furnace systems. This 0. 90" WC pressure switch serves as a critical safety component, ensuring the draft inducer motor is generating the required vacuum pressure before the ignition sequence initiates. Specifically engineered for York, Coleman, and Luxaire gas furnaces, this high fire switch prevents hazardous conditions like