Caleffi Series 257 iSolar BX Multi-functional Temperature Differential Controller

The iSolar™ BX is a multi-functional temperature differential controller with add-on system functions for use in a wide variety of solar thermal heating applications. iSolar™ BX is equipped with four relay outputs; three triac pump speed control relays and one standard relay. These outputs include two pulse width modulation (PWM) outputs that enable energy conservation measures for high-effi ciency direct current (DC) pumps. The controller is equipped with fi ve Pt1000 sensor inputs, two analog Grundfos sensor inputs, and one impulse fl ow meter input. Twenty six system confi guration options are predefi ned for control of a standard solar water heating system, drainback systems, supplemental space heating, multiple storage tanks, heat dump and storage tank booster heating.