... .3) More water can be supplied quickly for your family,from 80L~500L for your choice.4) For the system with double ... the closed loop, operating under the pressure.6) Intelligent control and automatic operation.7) Special anti-freezing function,work normally under -35C ... (Testing pressure: 1.2Mpa)Working principle:Installation Case: Solar hot water heating system,SRCC,Solarkeymark,ISO9001,100L~500L