McDonnell & Miller 324500 O-Ring

Maintain precise system pressure and eliminate leak paths with the McDonnell & Miller 324500 Tetraseal O-Ring. This pack of five high-performance seals is the engineered replacement for the discontinued 324435 part number, ensuring a direct fit without the need for field modifications. Designed as a critical boiler control replacement part, these o-rings are specifically optimized for low water cut-off (LWCO) and mechanical water feeder assemblies. They provide a pressure-tight interface for the McDonnell & Miller 47 series, 51 series, and 101A series units, preventing the standard degradation often seen in high-temperature hydronic environments. Fabricated from advanced Tetraseal elastomers, this 37-101 model gasket offers superior chemical resistance and thermal stability when compared to standard Buna-N alternatives. For contractors, these HVAC gaskets are essential for routine maintenance or emergency repairs on vintage and modern steam and hot water systems, ensuring long-term seal integrity in demanding commercial and industrial boiler applications.

• Direct Cross-Reference: Exactly replaces the legacy 324435 part number to maintain 37-101 specifications across multiple generations of feeders.
• Broad Series Compatibility: Engineered for seamless integration with McDonnell & Miller 21, 25A, 47, 51, 53, and 101A series water feeders and cut-offs.
• High-Durability Tetraseal Construction: Advanced material properties resist the elastic deformation and thermal hardening common in steam-loaded environments.
• Contractor 5-Pack: Provides essential backup inventory for multiple service calls, ensuring job-site readiness for boiler valve sealing procedures.
• Leak Prevention: Precision-molded tolerances prevent bypass and ensure the internal float mechanism maintains accurate water level detection.

Is the 324500 a direct replacement for the 324435 o-ring?
Yes, the McDonnell & Miller 324500 is the direct, updated part number for the 324435. It retains the same dimensions and technical capabilities as the original 37-101 model seal.

What series of water feeders are compatible with this Tetraseal O-Ring?
This seal is optimized for McDonnell & Miller 21, 25A, 47, 51, 53, and 101A series units. It is frequently applied to mechanical water feeders and low water cut-off bypass valves.

Why use Tetraseal gaskets instead of standard rubber o-rings in boiler applications?
Hydronic systems subject seals to extreme temperature cycles and chemical treatments. Tetraseal o-rings are specialized for these conditions, preventing the hardening and cracking that lead to boiler leaks.

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.