The Weil-McLain 511-624-545 Pressure Switch is a critical safety control designed to monitor air pressure within compatible HVAC heating systems. It works by detecting proper draft or airflow conditions and allowing the boiler to operate only when safe pressure levels are achieved, helping prevent unsafe operation. Commonly used in Weil-McLain gas-fired boilers and related heating equ... https://www.partshnc.com/511-624-545-weil-mclain-pressure-switch