Caleffi Series 257 iSolar Plus Multi-functional Temperature Differential Controller

The iSolar™ 257 series are multi—functional temperature differential controllers that provide complete control of the solar thermal system for safe and long—lasting operation. The microprocessor based controller monitors and controls thermal solar systems by means of a collector sensor and a storage tank sensor. The controllers also perform important system monitoring and safety functions. The system parameters and measured values can be changed and viewed on the large LCD display. The controller is equipped for up to four temperature sensor inputs and one or two 120 VAC outputs (some models) for activating the solar circuit pump and second 120 VAC output for activating a valve or second pump. The controller is additionally equipped with VBus® for two-way communication between modules, PC’s or data loggers.