... solar water heater 1. 100L-1000L 2, CE/PED approved, high quality 3, OEM/ODM 4, Food material SUS304/316L Heat pipe ... difference circulation pump 5. Flow rate indicator 6. Return circuit connector 7. Safety valve 8. Expansion vessel connector9. Return circuit ... connector 10. Wall mounting 11. Expansion vessel: 5L, 8L, 12L, 19L, ...