Lennox 33W18 Pressure Switch 322027-701 What is the primary function

What is the primary function of the S11 switch in this kit

Resilient Seating: Non-metallic disc-to-metal seating resists corrosive mineral deposits and ensures automatic reseating after discharge

erratic burner flames

High Pressure Precision: Supports 140 PSI max operating pressure for robust performance in high-velocity air systems

Lennox 33W18 Pressure Switch 322027-701 What is the primary functionThe Lennox 33W18 is a critical two stage combustion air pressure switch designed for specific Lennox high efficiency furnace models. This differential pressure switch ensures secondary heat exchanger safety by monitoring the inducer motor's draft performance. With a dual setpoint configuration of 0. 20" WC 1. 32" WC, this switch accurately sequences the low fire and high fire combustion cycles. Proper calibration of the Lennox 33W18 pressure switch is