McDonnell & Miller 2 Switch

The McDonnell & Miller 110000 (Model No. 2) is a high-performance, single-pole double-throw (SPDT) auto reset general purpose switch engineered for field replacement and system upgrades. Designed to operate on 120Vac/240Vac circuits, this versatile component is the standard for adding low water cut-off (LWCO) functionality or integrated alarm signaling to existing mechanical feeders. Technically robust, it features an electrical rating of 10.2A at 120VAC and 5.1A at 240VAC, ensuring reliable switching for motor loads or pilot duty applications. This switch is a direct-fit replacement for the McDonnell & Miller Series 47-2, 51-2, 63, and 247-2 boiler water feeders. By utilizing an automatic reset mechanism, the 110000 switch eliminates the need for manual intervention after a temporary low-water condition has been corrected, maintaining continuous system safety and operation. Whether you are performing a Model 2 switch replacement or configuring a new make-up water system, this UL-listed and CSA-certified component provides the precision required for mission-critical HVACR boiler controls.

• Broad Compatibility: Seamlessly integrates with McDonnell & Miller Series 47, 51, 51-S, 53, 63, 247, and 847 water feeders.
• Dual Voltage Versatility: Rated for both 120Vac and 240Vac, providing flexibility for diverse residential and commercial boiler wiring.
• Automatic System Recovery: The auto reset feature ensures the system returns to normal operation immediately once water levels are restored.
• SPDT Logic: Single-pole double-throw configuration allows for simultaneous low-water cutout and auxiliary alarm or light notification.
• Industrial Build Quality: High-ampacity motor switch ratings (10.2A @ 120VAC Full Load) handle demanding mechanical cycles without failure.

How do I wire the McDonnell & Miller 110000 for a low water cut-off?
The SPDT terminals allow for a "break" on low water. Ensure the burner circuit is wired through the common and normally closed terminals, while an optional alarm can be wired to the normally open terminal to signal a cutout event.

Can the 110000 replace a manual reset switch?
Yes, however, most technicians prefer this auto reset general purpose switch for standard water feeders to avoid nuisance lockouts during minor fluctuations. For applications requiring a manual lockout, the 110100 (Model 2-M) would be the specific alternative.

Is this switch suitable for high-pressure steam applications?
While the switch itself is rated for high electrical loads, its application is limited by the pressure rating of the water feeder housing it is installed in (e.g., 25 psi for Series 47 or 50 psi for Series 63). Always check the master feeder specifications.

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.