... your choice.4) For the system with double coils in tank,it can operate with traditional heating energy equipment,such as electric ... .5) Adopts the closed loop, operating under the pressure.6) Intelligent control and automatic operation.7) Special anti-freezing function,work ... pressure: 1.2Mpa)Working principle:Installation Case: Solar hot water heating system,SRCC,Solarkeymark,ISO9001,100L~500L