Fail-Safe Operation: Integrated spring return mechanism ensures the valve returns to a normally closed position during power loss

The physical dial on the board allows you to adjust the ventilation schedule between 1 and 60 minutes per hour to meet the required airflow rate measured at the intake duct

Whether you are performing a motor swap or a full system overhaul

preventing unnecessary shutdowns while protecting against prolonged low-pressure states

Universal Compatibility: Serves as the primary replacement for MA-6501 and MA-7501 series

Lochinvar & A.O. Smith 100093859 Assembly R-410A Fail-Safe Operation: Integrated spring returnThe Lochinvar & A. O. Smith 100093859 Manifold Door Assembly is a high precision OEM replacement engineered for high efficiency gas fired boilers and residential FVIR water heaters. As a veteran grade burner door assembly, this kit is essential for maintaining the sealed combustion chamber's integrity, ensuring optimal thermal efficiency and safe manifold pressure regulation. The assembly integrates a robust door port designed to withstand high