McDonnell & Miller 157-A-1 Replacement Casting

The McDonnell & Miller 157-A-1 Replacement Casting is a critical heavy-duty component designed for the 157A Series liquid level controls and low water cut-off systems. This OEM replacement body features 1-1/4 inch NPT equalizing tappings, providing the necessary structural integrity for steam boiler applications with pressures up to 150 psi. Built for industrial environments, this cast iron replacement ensures a precise fit for the integral water column, maintaining safe operating levels and protecting the burner circuit from dry-fire conditions. When performing a teardown or boiler maintenance, replacing a compromised or scaled casting with an authentic 157-A-1 body is the professional standard to ensure long-term pressure vessel reliability. It is engineered to house the float and rod assembly, providing the exact clearance required for the Monel bellows and snap-action switch mechanisms to function without binding.

Key Benefits

• Direct Compatibility: Specifically cast for McDonnell & Miller 157A Series controllers, ensuring exact alignment of 1-1/4 inch tappings.
• Industrial Durability: Rugged cast iron construction designed to withstand the thermal cycling and high-pressure demands of commercial steam boilers.
• System Safety: Restores the integrity of the float chamber and water column, essential for accurate liquid level control.
• Technical Precision: Machined to OEM specifications to prevent leaks and ensure a proper seal with the head mechanism gasket.

Common Questions

• Does this include the head mechanism? No, the 157-A-1 is the replacement casting (body) only. The head mechanism, float, and gaskets must be ordered separately if needed.
• What size are the equalizing tappings? This model features 1-1/4 inch NPT tappings, which distinguishes the 157A series from the standard 157 series (1 inch NPT).
• Can this be used on high-pressure boilers? This casting is rated for a maximum steam pressure of 150 psi, making it suitable for both low and high-pressure HVACR applications.

This item is not eligible for free shipping.

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.