Hot water cylinders are continually increasing in popularity and can now be found in most homes across the UK. They are commonly used to ensure that a copious amount of stored hot water is available on demand for a multitude of domestic uses. Unvented cylinders are connected directly to the mains water system which means they offer high water flow rates to provide higher water pressure for showers and baths.
The unvented hot water cylinder doesn’t require a feeder tank in the loft as it works straight from the mains water supply which frees up valuable space in the property. Unlike vented cylinders, the unvented cylinder does not rely on gravity to function, so they can be installed almost anywhere on a property. Regardless of these different functionalities of hot water cylinders, both styles are manufactured from high quality stainless steel to ensure long life and durability.
As these are sealed systems, unvented cylinders require an expansion vessel to allow expansion of water in the system as it heats up. Without an expansion vessel, the water system cannot allow cold water to expand as it is heated therefore creating a dangerous environment. This is because when water is heated, the pressure can increase by up to 4.5%. An expansion tank allows for this increased pressure which means it is a vital part of any sealed system.
The unvented indirect cylinder needs to be installed by a qualified specialist which means they tend to be more expensive to install than the traditional vented hot water system.