The Lau 60772501 uses a fixed hub with a 1/2-inch bore

Corrosion Resistance: Stainless steel ball and stem prevent premature wear in high-duty cycle environments

preventing ignition if a blocked flue or restricted heat exchanger is detected

ensuring reliable operation across a fluid temperature range of 35 to 284°F

providing a critical pneumatic link between the inducer motor

Lennox 78W57 Pressure Switch 321894-709 The Lau 60772501 uses aThe Lennox 78W57 Pressure Switch is a high precision, factory authorized OEM replacement engineered for draft proving and airflow safety monitoring in Lennox heating and cooling systems. Specifically calibrated to actuate at 0. 27" WC (Water Column), this SPST pressure switch features a 1 4" barb connection for secure integration into existing 24V control circuits. Designed as a direct replacement for Lennox part number 101572 04, it is a critical