McDonnell & Miller 311200 Float and Gasket

The McDonnell & Miller 311200 Float and Gasket is a critical OEM replacement kit for Series 21 (Model 21-30) mechanical water feeders. As a veteran-grade boiler replacement part, this assembly is engineered to maintain precise fluid level control in condensate receiver tanks and industrial boiler systems. The 4-3/4” copper float and high-grade replacement gasket ensure a professional-grade seal and reliable proportional feed action. Supporting a maximum water supply pressure of 150 PSI and a maximum vessel pressure of 35 PSI, this kit is designed to handle demanding low-pressure steam and hot water boiler applications. By replacing the worn float-operated mechanism, contractors can eliminate inefficient water level fluctuations and prevent potential system flooded conditions or dry-fire hazards in HVAC mechanical systems. This heavy-duty float and rod assembly is built for seamless integration into make-up water feeders used in systems exceeding 5,000 sq. ft. of steaming capacity.

Key Benefits

• Compatible with McDonnell & Miller Series 21 and 221 make-up water feeders.
• Features a proportional feed action to maintain a constant minimum safe water level.
• Includes a durable soft seat design for a positive, leak-free seal against supply pressure.
• Specifically rated for boiler receiver tanks with fluid temperatures up to 120°F.
• Ensures boiler maintenance standards by preventing overfilling and optimizing return condensate space.

Common Questions

Is the McDonnell & Miller 311200 compatible with the Series 221?
Yes, this replacement float and gasket kit is designed to fit both the Series 21 and Series 221 mechanical level controls.

What is the maximum pressure rating for this assembly?
The unit supports a maximum water supply pressure of 150 PSI (10.5 kg/cm²) and a maximum vessel pressure of 35 PSI.

Does this kit include the gasket needed for installation?
Yes, the 311200 kit includes the necessary replacement gasket to ensure a proper seal between the float chamber and the valve assembly during maintenance.

Disclaimer: While we strive for 100% accuracy, product data and specifications are subject to change. Please contact our team to confirm compatibility or technical details before purchasing.