Unvented Cylinders Unvented Cylinders
Unvented cylinders do not require a stored cold water supply as they are fed directly from the cold water mains. This results in improved pressure and flow rates at the taps and greater shower performance, without the need for pumps. Expansion is either taken up inside the cylinder as with the Megaflo, or externally in a separate expansion vessel, such as with unvented cylinders from Oso or the Santon Premier Plus. Unvented cylinders are available as either indirect (boiler heated) or direct (electrically heated) models. Most Unvented cylinders are manufactured from stainless steel and have a 25 year guarantee.
Prior to installing an unvented cylinder the following points should be considered: Carry out water mains pressure and flow tests, check discharge requirements, allow access for future servicing and maintenance.
Legislation
Unvented cylinders installations must comply with UK Building Regulations, Schedule 1 Part G3.
It is a legal requirement that the local authority Building Control Officer be notified of any proposed installation of unvented storage water heating systems over 15 litres. This notice should include:-
(a) Name, make, model and type of hot water storage system to be installed.
(b) Name of the body which has approved or certified the system.
(c) Details of the ‘competent installer’ intending to carry out the work, including details of any current Registered Operative Identity Card held, and the issuing body
A "competent" person is described as one holding a current registered operative identity card for the installation of unvented domestic hot water storage systems. A registered competent person is qualified to self certify the installation of an unvented hot water cylinder.