McDonnell & Miller 53-2 Water Feeder

The McDonnell & Miller 53-2 (Part Number 137100) is a dual-function mechanical water feeder and low water cut-off designed for heavy-duty service in low-pressure steam and hot water boiler applications. Engineered for systems with a maximum vessel pressure of 75 PSI, this unit features 1-inch NPT connections and a high-capacity feed mechanism. The snap-acting SPDT switch provides precise electrical control for burner circuits and alarm signaling, ensuring the boiler maintains the critical water line without constant manual intervention. For technicians servicing older or high-capacity residential and commercial boilers, the 53-2 is a standard for reliability when handling low water safety requirements. Its mechanical float-style operation avoids the complexities of electronic sensors in high-scale environments. Correct boiler water level control via the 53-2 prevents dry-firing and maintains system thermal efficiency by ensuring the automatic water feeder activates only when necessary, compensating for evaporation and minor system leaks.

• Dual-Function Operation: Combines reliable mechanical feeding with a fail-safe low water cut-off switch.
• High Pressure Rating: Rated for up to 75 PSI, making it versatile for both steam and hot water vessels.
• Precise Electrical Control: Equipped with a snap-acting SPDT switch for definitive circuit interruption and signaling.
• Rugged Construction: Designed with 1" NPT connections to accommodate high-flow requirements in larger boiler systems.
• Field-Serviceable Design: Built for longevity in mechanical rooms, allowing for straightforward inspections and maintenance.

Common Questions

Is the McDonnell & Miller 53-2 compatible with both steam and hot water boilers?
Yes, this unit is engineered for both low-pressure steam and hot water systems, provided the vessel pressure does not exceed the 75 PSI limit.

What is the difference between a Model 53 and a Model 53-2?
The Model 53-2 includes the integrated SPDT switch for electrical low water cut-off functionality, whereas the base Model 53 is strictly a mechanical feeder.

How do I ensure the feeder does not overfill the boiler?
Proper installation at the manufacturer's recommended water line and regular blow-down of the float chamber are essential to prevent sediment buildup from affecting float buoyancy.

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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.