... 15years 2.Certificate:SRCC,CE,Solar Keymark,ISO 3.Deliver time:Within 3days water heat pump DescriptionVacuum tube58-1800mm co ... long life span ,and the vacuum tubes can work individually,so if the only one of them can ... 't work,it won't influence on the others.The ... the tap water flow in the tank ,if the water is full,it will close the valve automatically solar water heat pump( ...