ISCS stands for Integrated Solar Control System. This is the summary of devices, sensors and actuators, all integrated into one, easy to manage system. The ISCS allows do-it-yourselfers to easily build a solar heating system. The ISCS contain the fill/drain valve, pressure valve, expansion tank, pump, digital controller, heat exchanger, flow meter, pressure meter, one way valve, vacation bypass. All pre plumbed so there is no need to hire a plumber. Simply plug the solar collectors into one end of the ISCS and connect the hot and cold pipes to your water tank. the ISCS conveniently mounts to the wall and plugs into an 110 VAC outlet.