installing this OEM-spec heating system thermocouple ensures the burner circuit maintains proper continuity and safety shut-off functionality

20" WC SPST air pressure switch functions as a critical safety limit

The Johnson Controls A-4000-144 is a professional-grade safety relief valve designed specifically for pneumatic control systems and air compressor accessories

This typically indicates an obstruction in the venting system

York S1-2940-3161 Switch Els PW 17895 installing this OEM-spec heating systemThe York S1 2940 3161 Fan and Limit Switch is a critical OEM replacement component designed for precise thermal regulation within HVACR systems. This reliable furnace limit control is factory calibrated with a 105F opening temperature and a 120F closing temperature (105Op 120Cl), ensuring the blower fan cycles correctly to maximize airflow efficiency and prevent heat exchanger overheating. As an HVAC high limit switch, it provides an essential safety