Vaillant wall-hung boiler repair Q&A; the main function of the expansion tank
The main function of the expansion tank is to accommodate the excess water produced during the heating process of the wall-hung boiler when the water is heated and expands. According to the different system water capacity, expansion tanks of different models (6L, 8L or 10L) are equipped. There is a rubber film inside the expansion tank. One side of the film is filled with nitrogen at a pressure of 0.8 bar, and the other side is filled with water. When the system water expands due to heat, it compresses the nitrogen on the other side to accommodate the excess water in the system. The nitrogen pressure in the expansion tank has been pre-filled at the time of leaving the factory, and during the use process, regular checks on the pressure are required.
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