providing seamless mechanical and electrical compatibility with legacy unit heaters

Common Questions What is the purpose of the 45-second delay on the MP54

and controlling the igniter heat-up sequence

Dual-Mode Functionality: Supports both single-probe point level detection and three-probe differential control for automated pump cycles

Lochinvar & A.O. Smith 100277781 Control 321894-706 providing seamless mechanical and electricalThe Lochinvar 100277781 Control (Model FB751 1251) is an integrated control board engineered specifically for Crest Heating Boilers. As a critical OEM replacement part, this module manages the firing sequence, ignition control, and safety parameters for high efficiency hydronic systems. This model is a direct boiler part replacement for units with serial numbers beginning with 4015, ensuring seamless integration with existing HVAC wiring harnesses and