... 24/7 300L 500L 1000L Split Pressurized Solar Water Heater Split pressurized Type composite:solar collector+storage tank+controller+ ... the water tank does not reach Tmax, Electric Heating Element will start to work automatically. 3. Feature:1) ... 19mm,optionalHeat exchanger materialCopper, stainless steel, optionalFree components:Electric heater, Magnesium rod, T/P valve, Pressure reducing valve Water ...