McDonnell & Miller 313600 Float and Gasket

The McDonnell & Miller 313600, also identified as model 37A-130, is a critical replacement float and gasket assembly engineered for 847 Series and 851 Series mechanical water feeders. As a veteran-grade low water cut-off part, this kit includes a high-durability float, dedicated rod, and the necessary flange gasket to ensure a pressurized seal during installation. Designed for both steam and hot water boiler applications, it maintains a precise minimum safe water level, preventing dry-fire conditions that lead to cracked heat exchangers or catastrophic system failure. This HVAC replacement part is specifically calibrated for the mechanical linkages found in the 851, 851S, and 847 controls, facilitating continuous maintenance of water levels independent of electrical sensors. When performing boiler control maintenance, replacing the 313600 assembly is standard procedure for units exhibiting logged floats or compromised gaskets to restore reliable makeup water feeder operation.

• OEM Compatibility: Precision-fit for McDonnell & Miller 847 and 851 series make-up water feeders.
• Complete Assembly: Includes the float, 335700 float rod, and 335400 head gasket for a comprehensive boiler repair.
• System Protection: Ensures accurate buoyancy response to actuate the feed valve, preventing low-water emergencies.
• Industrial Build: Heavy-duty construction designed to withstand the thermal cycling and scaling common in commercial steam systems.

How do I know if my McDonnell & Miller float is water-logged?
Technicians should check if the burner fails to cut off or if the feeder is constantly calling for water. A water-logged float loses buoyancy, staying submerged and failing to actuate the mechanical linkage. If the float feels heavy or you hear liquid inside when shaken, the 313600 float replacement is required.

Is this kit compatible with the 851-S model?
Yes, the 37A-130 assembly is the correct specification for the 851, 847, and 851-S series. Always inspect the head gasket surface for pitting or debris during installation to ensure a leak-free seal.

Can I replace just the gasket or float separately?
While individual components exist, installing the full 313600 kit is recommended during any 5-year teardown or annual inspection to ensure the rod threading and float integrity are matched, reducing the risk of mechanical binding.

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.