... used for other function, such as warming Solar heat pipe heater working principle: 1. The collector absorbs solar energy and ... Heating Element will start to work automatically Solar heat pipe heater working station component 1. Operating screen 2. Manometer 3. ... . Safety valve \8. Expansion vessel connector9. Return circuit connector 10. Wall mounting 11. Expansion vessel: 5L, 8L, 12L, 19L, 20L, ...