This genuine Carrier replacement part functions as a critical thermal overload relay

the TX3N2 is strictly designed for R22 refrigerant

preventing the wide temperature swings common in standard on/off systems

providing superior thermal resistance and protection against electrical breakdown in high-ambient environments

The valve operates on a standard 24VAC solenoid circuit and is rated for multi-fuel versatility

Lochinvar & A.O. Smith 100277940 Board 30067439-890 This genuine Carrier replacement partThe 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