... solar water heater 150L Solar keymark, CE, ISO Red copper heat pipe, transfer heat quick 58-1800mm tube 1. Working principle: The pressurized water ... heat pipe makes the whole system can bear pressure.2. Technical Parameters: Water tankInner tank1.2mm thickness SUS304/2B stainless steelOuter tank0 ... , so it can be working even have an tube broken. 2) The red copper in the inner tube, the heat transfer ...