CO HS 25L diaphragm vessels absorb water volume fluctuations in the closed system of a central heating system, maintaining constant pressure and helping to reduce energy consumption. The wide range of available diaphragm vessels meets the requirements of various heating systems and sizes. In a closed central heating system, water cannot be compressed and any increase in water volume due to a rise in temperature is absorbed by the diaphragm vessel. When the water is cold, the pre-pressure of the vessel presses on the diaphragm. When the temperature rises, the increasing volume of water presses on the diaphragm and water flows into the tank providing additional space for the system. As the temperature drops, the air absorbs the forces and the water flows back into the system. This allows the system to maintain pressure, helping to reduce the energy consumption of the central heating system.