the B1256559 is the direct factory-authorized upgrade for the discontinued B1256552 and maintains identical electrical specifications

While optimized for the KH8 damper crank arm

Drop-in Compatibility: Standardized 24V wiring connections facilitate rapid replacement in Trane HVAC units

Ensure the bronze seats are cleaned or replaced if the check valve assembly does not seal completely

Veteran HVACR technicians prioritize the AFA series for its external superheat adjustment

Lochinvar & A.O. Smith 100208496 Control Board 30067439-890 the B1256559 is the directThe Lochinvar & A. O. Smith 100208496 Control Board is a critical OEM replacement part designed to maintain the operational integrity of high efficiency commercial boilers and water heaters. As the direct replacement for RLY2107, this relay control board manages executive switching functions, including the 24VAC signal distribution to the ignition module and pressure switch systems. This board is essential for coordinating the two speed blower motor