an open circuit suggests the protector has tripped or failed internally

For contractors and technicians

this seal is designed for use across the Bunn Ultra series

600 BTU/hr depending on manifold pressure—it provides the exact fuel-to-air ratio required for safe atmospheric burner operation

System Safety: Crucial for maintaining the air-fuel ratio by preventing unmetered air from entering the combustion chamber

McDonnell & Miller 312200 Gasket an open circuit suggests theMaintaining the integrity of boiler water feeders and liquid level controls requires high performance sealing components designed for steam and hydronic environments. The McDonnell & Miller 312200 Gasket is a critical replacement valve bracket gasket engineered specifically for Series 21, Series 25A, and Series 27 units, including the 27W model. As the direct updated version for 311100, this part ensures a precision fit for mechanical water feeder