Lennox 15W56 .43" WC SPST Pressure Switch

This Lennox 15W56.43-inch WC SPST Pressure Switch is a safety device in HVAC systems that measures and regulates the pressure of the air moving within a system. This SPST switch is designed to turn on at 0.43 Inches water column pressure. The pressure switch which is designed for use in furnace detects low or high air pressure within the venting system to ensure the system operates within safe limits. When there is an anomalous pressure, the switch breaks the electrical circuit, preventing the furnace from starting and hence preventing problems such as incomplete combustion or overheating.