When heating water directly from a mains supply, one of the highest performing systems is an unvented mains pressure system, these systems require the use of unvented hot water cylinders.
Unvented hot water cylinders are a means of storing and then distributing hot water in the home; they are very efficient and offer many advantages. Unvented hot water cylinders are so-called because they are not open to the air in any way which means that they heat the water stored in them quicker than vented cylinders which are open to the atmosphere. Because this kind of system is supplied directly from the mains and not from a cold water storage tank, the pressure contained in the system is much greater than in vented systems as no pressure can escape – this gives you much greater water pressure from your taps and shower heads.
Unvented hot water cylinders can be made from copper, low-carbon steel or stainless steel. Vaillant’s latest range of cylinders – the uniSTOR range – are all made from stainless steel and are capable of withstanding pressures of up to 10 bar and have capacities that range from 125-310 litres. All of Vaillant’s cylinders are fully compatible with Vaillant system boilers and other manufacturers’ boilers.