... work in the bad weather with high efficiency. 3) Use the electric heating water tank specially for solar water heater. 4) Double energy: You ... pump expansion 3) Collector tube dimensions: 58mm x 1.8m, 47mm x 1.5m 4) Water capacity: 100L, 150L, 200L, 250L, 300L, 350L ... pump expansion 3) Collector tube dimensions: 58mm x 1.8m, 47mm x 1.5m 4) Water capacity: 100L, 150L, 200L, 250L, 300L, 350L ...