Robust construction designed to withstand repeated thermal cycling and manual strain on the control head

for the 1/2" MPT center branch

provided the target outlet pressure falls within the 5-12" WC range

For contractors and technicians

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

McDonnell & Miller 312200 Gasket Robust construction designed to withstandMaintaining 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