McDonnell & Miller FPC-1000 Control

The McDonnell & Miller FPC-1000 (Part No. 144704) is a field-configurable electronic low water cut-off (LWCO) engineered for high-performance protection in both steam and hot water boiler applications. As the consolidated direct replacement for 750-MT-120, PSE-800, and Series 750 legacy controls, this "boilerwize" unit allows contractors to simplify truck stock by serving as a universal low water cut-off. The FPC-1000 features a dual-voltage design, supporting 24V or 120V operation, and can be easily toggled between automatic and manual reset modes through the integrated tri-function button. This probe-type LWCO utilizes patented conductivity-monitoring technology to distinguish between true low water logic and transient foam or turbulence, preventing nuisance burner shutdowns. Designed for rugged hydronic boiler safety, it features brass-threaded metal-to-metal seals for a leak-free environment and includes multi-function LEDs for real-time status diagnostics of power, reset mode, and critical low water conditions. Note: This model is supplied without a probe and requires a compatible McDonnell & Miller electrode for full functionality.

• Universal Application: Field-configurable for steam or hot water systems, functioning as a primary or secondary safety device for residential and commercial boilers.
• Voltage Versatility: Direct internal selection for 24VAC and 120VAC power requirements, eliminating the need for multiple SKUs on the job site.
• Advanced Maintenance: Includes a self-cleaning probe feature that actively minimizes scale buildup to extend operational intervals in hard water conditions.
• Contractor-Friendly Design: Features wrench flats for high-torque tightening and a redesigned enclosure with accessible wiring knockouts for streamlined installation.
• Code Compliance: Engineered to meet strict ASME CSD-1 requirements for commercial boiler safety controls.

Common Questions

Yes, the FPC-1000 is the direct engineering successor to the McDonnell & Miller 750-MT-120. It provides superior field-configurability and enhanced diagnostics while maintaining backward compatibility with existing system footprints.

Correct. The control is dual-purpose. During initial setup, the technician uses the tri-function button to define the boiler type (steam or water), ensuring the low water cut-off sensitivity is matched to the specific conductivity of the medium.

The button serves as a push-to-test diagnostic, a manual reset for lockout conditions, and the primary interface for field-configurable control settings during the commissioning phase.

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.