The Maxitrol 12A39 Vent Limiter is designed for use with 325-5 Series gas pressure regulators in HVAC systems. It functions by limiting the release of gas into indoor spaces during regulator operation, enhancing safety without requiring external vent piping. Commonly applied in furnaces, boilers, and other gas-fired equipment, this vent limiter ensures compliance with safety standards... https://www.partshnc.com/12a39-maxitrol-vent-limiter-for-325-5-series