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

for the 1/2" MPT center branch

reducing excessive energy consumption while protecting the sensitive bellows within the operator from manual over-rotation or tampering

For contractors and technicians

McDonnell & Miller 312200 Gasket System Safety: Crucial for maintainingMaintaining 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