... take into account long time of collector in high temperature and other characteristics of the system.Technical ... of pump:4pcs,< 600W Suitable power of electrical heater:1pc,<1500W INPUT:One Sensor for collector(pt1000, ... a, heating return rising, b. temperature controling, c: high temperature reducing. d: by-pass pipeHoliday fucntionHND HND Manual ... display) Solar working station for solar water heater