Lochinvar & A.O. Smith 100277940 Board 321894-709 Enhanced Control: Integrated auxiliary switch

Enhanced Control: Integrated auxiliary switch (1x SPDT) allows for precise end-stop verification or equipment sequencing

this is an internal mechanical rebuild kit

This OEM component is critical for maintaining discharge air temperatures during defrost cycles or when the heat pump's compressor cannot meet the building's thermal demand

An isolated coil allows the control circuit to operate independently of the chassis ground

Common Questions What is the maximum RPM for the L150 NBR spider

Lochinvar & A.O. Smith 100277940 Board 321894-709 Enhanced Control: Integrated auxiliary switchThe Lochinvar & A. O. Smith 100277940 Board is a critical low voltage connection board engineered for precision signaling in high efficiency heating systems. Specifically designed for the Knight KH055 285 fire tube boilers, this OEM replacement part serves as the central communication interface between the main controller and auxiliary system components. As a veteran technician knows, maintaining signal integrity in commercial water heating