The IBC Technologies P-337B Air Pressure Switch Kit is a replacement safety control designed for compatible IBC boiler systems. It monitors air pressure within the combustion or venting system and changes its electrical state when the required pressure level is reached, helping verify proper airflow before and during operation. Commonly used in high-efficiency gas boilers and related ... https://www.partshnc.com/p-337b-ibc-technologies-air-pressure-switch-kit-sl-g3