... water in the tank, providing accurate parameter. temperature feeler/Solar Water Heater Controller System is used to detect the ... (not standard, selection available ) 8,Electromagnetic valve parameter: DC 12V, AC 220V, pressurized valve and un-pressurized valve are available ... 12,Manual heating 13,Timing heating 14,Hot water circulation 15,Hot water pipe insulation 16,Low pressure protection 17 ...