BS 6798:2014

This standard BS 6798:2014 Specification for selection, installation, inspection, commissioning, servicing and maintenance of gas-fired boilers of rated input not exceeding 70 kW net is classified in these ICS categories:

• 91.140.10 Central heating systems

This British Standard specifies requirements for the selection, installation, inspection, commissioning, servicing and maintenance of gas-fired boilers for central heating and other purposes, which have a total rated heat input not exceeding 70 kW based on net calorific value. This includes cookers with integral boilers used to provide central heating.

It applies to boilers utilizing 1st, 2nd or 3rd family gases designed to operate in the condensing or non-condensing mode for the heating of domestic dwellings or domestic dwellings in commercial premises by the circulation of heated water in open or closed systems.

This standard does not apply to:

1. boilers with a rated input of over 70 kW; or

2. groups of boilers with individual ratings of 70 kW or less, but with aggregate inputs of over 70 kW as specified in BS 6644.

NOTE 1 Groups of boilers with individual ratings of less than 70 kW, but with a maximum aggregate input of ≤70 kW, may be installed to this standard but specialist advice on the system design, installation and control needs to be sought from the appliance manufacturer.

It is not applicable to the detailed design and installation of the whole heating system, which is specified in BS EN 12828, BS EN 12831:2003 (incorporating corrigendum January 2009) and BS EN 14336:2004 (incorporating corrigendum January 2009).

NOTE 2 With the publication of BS EN 12828, BS EN 12831 and BS EN 14336, BS 5449 has been withdrawn. These Standards are not aligned to UK design and installation practices; they cover commercial as well as domestic heating systems and exclude hot water. Consequently, these standards include UK national annexes covering all the relevant material from BS 5449.

NOTE 3 The installation of boilers with a rated input greater than 70 kW is covered by BS 6644. Additional requirements for the installation of back boiler units are specified in BS 5871‑1 and BS 5871‑2.

This standard applies to boilers which carry a CE mark and also to previously-used boilers which do not carry the CE mark (see 6.2.1).

NOTE 4 In this standard, heat input is expressed in terms of net calorific values (CV), unless stated otherwise. The ratio of gross to net heat input is approximately 1.11:1 for natural gas, 1.09:1 for propane, and 1.08:1 for butane.

NOTE 5 It is essential that persons carrying out the installation of any gas appliance are competent to do so. Clause 4 gives information on competence.

NOTE 6 Some clauses of this standard might be appropriate for the installation of pool and spa heaters. The manufacturer’s instructions might advise which parts are not appropriate. For example, for direct spa and pool heaters, no corrosion inhibitors or chemical cleaning are permitted.

NOTE 7 The general installation requirements for 3rd family installations specified by this standard also apply to gas installations supplied with LPG/air mixtures used in the Channel Islands or the Isle of Man, providing: any gas equipment being installed has been appropriately converted and is suitable for the gas being supplied, and the requirements of the standard do not conflict with local regulations or authorized local custom and practice.