The Kromschroder 84444900 Air Pressure Switch is a pressure-monitoring component designed for compatible gas-fired boilers, heating systems, and HVAC equipment. It detects changes in positive, negative, or differential air pressure and activates an internal microswitch when the preset pressure threshold is reached. This helps monitor combustion airflow and supports reliable equipment ... https://www.partshnc.com/kromschroder-84444900-air-pressure-switch