Lochinvar & A.O. Smith 100277781 Control

The 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 sensors. The board features an electronic control display interface that allows technicians to perform HVAC system diagnostics, adjust temperature set-points, and monitor flame sensing current in real-time. By utilizing advanced microprocessor-based logic, the FB751-1251 control module optimizes boiler energy efficiency and ensures the precise combustion air blower modulation required for the Crest series' high turndown ratios. Replacing a faulty Lochinvar control board with this authentic 100277781 component restores professional-grade reliability to the heating plant and prevents uncommanded lockouts in commercial boiler systems.

• Direct OEM Compatibility: Specifically designed as a drop-in replacement for Crest FB 751-1251 series boilers, ensuring full communication with Smart Touch interfaces.
• Advanced Sequence Logic: Manages the pre-purge, ignition, and post-purge cycles with high-precision timing to safeguard the heat exchanger.
• Integrated Diagnostics: Facilitates rapid HVAC troubleshooting by reporting specific error codes for sensors, switches, and gas valve malfunctions.
• Enhanced System Safety: Constant monitoring of low water cut-off, high-limit, and air pressure switch inputs to ensure safe operational boundaries.

Which boiler models use the 100277781 control board?
This module is primarily used in Lochinvar Crest models 751, 1001, and 1251. Always verify that your unit's serial number begins with 4015 to ensure the hardware revisions are compatible.

Does this board support 0-10V DC modulation?
Yes, the K Control FB751-1251 platform is designed to handle variable speed pump signals and BMS integration via the Smart System interface, supporting modern boiler system upgrades.

What should I check if the control shows "No Display"?
Before replacing the board, technicians should verify the ribbon cable integrity and check fuse F3 on the main integrated control to rule out simple power distribution failures.

This item is not eligible for free shipping.

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.