Aquasystem diaphragm expansion tanks from Hydroheat Supplies work by absorbing the increased volume of water that occurs when it is heated. For example heating water from 0 degrees celsius to 100 degrees celsius increases its volume by about 4.5 per cent.
Once the tank is connected to the system, the temperature increases and with it the water volume which then starts to fill the membrane. The water volume keeps increasing until the desired temperature is reached and at this stage the membrane occupies almost all of the space inside the tank.
Contact between the water and the internal surface of tank is avoided with the use of a pressurised air cushion. When the temperature gradually decreases so does the water volume and then due to the pressure of the air cushion the water starts to come out of the tank until the membrane is again its original size. A new cycle then begins.
Hydroheat Supplies stock a full range of diaphragm expansion tanks ranging from eight litres to 600 litres. Smaller sizes are also available in flat, pancake versions. All VR, VRV, VS and VSV diaphragm expansion tanks are manufactured, tested, checked and certified by Hydroheat Supplies.