this heat pump defrost control utilizes a shunt jumper system to select precise defrost "curves

offering superior dielectric strength compared to lower-rated alternatives

protecting the SPDT contact system from moisture and contaminants

Designed specifically for compatibility with Trane "A" and "B" series gas-fired units

Lochinvar & A.O. Smith 100208461 Board Control 30067439-890 this heat pump defrost controlThe Lochinvar & A. O. Smith 100208461 Board Control User Interface is a critical replacement component engineered for high efficiency commercial water heaters and boilers. Also identified as RLY2210 and RLY2210K, this integrated control board manages the system's operational logic, facilitating communication between the sensors and the firing mechanism. Designed for various Lochinvar Knight and A. O. Smith Cyclone series models, it replaces legacy