How It Works

In a closed hot water circuit, the water cannot be compressed so any increase in volume, created by an increase in temperature, has to be accommodated by an expansion vessel. When water is cold, the pre-charge pressure presses the diaphragm against the tank. As the temperature in the system increases, with the associated increase in pressure and volume, the expanded water pushes against the diaphragm and water enters the vessel, providing additional volume.When the temperature decreases, the pre-charge pressure forces the water back into the main heating circuit , maintaining a constantpressure helping to reduce energy consumption