Un-vented Hot Water
What is an Un-Vented Hot Water System?
An un-vented hot water system is a hot water storage system that has a hot water storage vessel which does not incorporate a vent pipe to the atmosphere. Un-vented hot water systems heat up quickly and are more efficient at retaining water temperature but only suitably qualified engineers are allowed to install them.
Global Energy Direct supply a wide range of un-vented hot water heating products and also provide Logic and BPEC un-vented hot water training courses for installers.
An un-vented hot water system differs from conventional OPEN VENTED systems in that no open vent pipe is provided. Therefore the several functions of the open vent pipe have to be performed in other ways. It is useful here to note the distinction, common to both the Water Regulations and the Building Regulations, between non-storage and storage systems.
British Board of Agrement (BBA) Requirements
The “Approved Document” states ‘Any un-vented hot water storage system should be in the form of a proprietary unit or package which is the subject of a current British Board of Agrement (BBA) certificate’.
‘Unit’ means a hot water storage system, incorporating factory fitted safety devices to prevent backflow, control working pressure, relieve excess pressure and accommodate expansion.
‘Package’ means a hot water system incorporating factory fitted safety devices, and supplied by the manufacturer with a kit, containing other operating devices to prevent backflow, control working pressure, relieve pressure and accommodate expansion, to be fitted to the unit by the installer.
Only an Approved Installer as defined in the BBA Certificate can undertake the installation of a unit or packaged system.
‘Approved Installer’ is a company or firm that holds a current Registered Operative Identity card for the installation of unvented hot water storage systems issued by:
- Construction Industry Training board (CITB); or
- The Institute of Plumbing; or
- The Association of Installers of Unvented Hot Water Systems (Scotland and Northern Ireland); or
- Operatives and employed by companies included on the list of Approved Installers published by the BBA; or
- An equivalent body (e.g. Logic Certification).
Such companies or firms must undertake to:
- Install systems certificated by the BBA and to do so in accordance with the relevant current BBA Certificates.
- Employ appropriate management and design staff, the latter experienced in unvented hot water storage systems.
- Employ Registered operatives and Trainees* on the installation of unvented hot water storage systems.
- Maintain effective and up-to-date records of all unvented hot water storage system installations undertaken by them.
- Inform the relevant local authority (obtain the necessary approval/warrant) and in addition the BBA or their representative of all unvented hot water storage installations at appropriate stages; such stages include a Building Regulations Approval or Warrant (in Scotland); and on completion of the installation.
- Provide adequate operative supervision/control to ensure installations conform the relevant BBA Certificate.
- Institute and maintain an arrangement to certify that each unvented hot water storage installation has been carried out in accordance with the relevant BBA Certificate.
- Rectify any installation that they have carried out and which is subsequently shown not to confirm to the relevant BBA Certificate.
Attached to the unit supplied by the manufacturer will be a document that must be completed by the installer or operative. The detachable part of this document must be sent to the BBA for documentation. The other half should be left with the occupants for future reference.
