McDonnell & Miller 351800 Hook-Up

The McDonnell & Miller 351800 Hook-Up (Model SA259-24) is a critical upper quick hook-up fitting designed for seamless integration with Series 47 and Series 47-2 mechanical water feeders. This professional-grade component also serves as a direct replacement part for Series 42S-A, 42A, and 64-A low water cut-offs (LWCO). By utilizing this specific boiler control fitting, technicians can ensure precise water level monitoring without the intensive labor of custom piping. The SA259-24 assembly is engineered to withstand the rigorous thermal cycles of steam heating systems, maintaining the integrity of the equalizing line. It allows for rapid field installation or repair of pump controllers and safety limits, ensuring the burner circuit remains protected against dry-fire conditions. For contractors managing commercial boiler maintenance, this OEM fitting provides the exact tolerances required to restore factory-spec performance to legacy and modern McDonnell & Miller water level controls.

Key Benefits

• Ensures accurate water level control by maintaining proper alignment of the upper equalizing line.
• Compatible with a broad range of legacy systems including 42A, 47, and 42S-A Series.
• Simplifies the boiler repair process by eliminating the need for complex field-fabricated piping.
• Manufactured to OEM specifications to prevent leaks and ensure long-term pressure vessel integrity.
• Facilitates reliable communication between the low water cut-off and the burner circuit.

Common Questions

What is the difference between an upper and lower quick hook-up for Series 47?
The McDonnell & Miller SA259-24 is the upper fitting specifically designed to connect to the top of the gauge glass or water column. For a complete installation, it is often paired with a lower hook-up, such as the SA159-24, to ensure the entire control unit is balanced within the steam environment.

Can I use the SA259-24 on a 64-A series low water cut-off?
Yes, the 351800 assembly is documented for use with the 64-A series model, providing a secure upper connection for level-sensing applications in steam boilers.

Does this kit include the gauge glass or gaskets?
This SKU (351800) typically covers the upper quick hook-up metal assembly. It is a standard procedure for technicians to source separate gauge glass and high-temperature gaskets when performing a full overhaul of the water column interface.

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.