Part 8 Appliances & Ventilation


Question Mar 2012: My customer wants to replace their LPG instantaneous water heater with a similar appliance - is that allowed?

Answer: All instantaneous LPG water heaters presented for examination by BSS Examiners are acceptable if they pass the BSS checks applicable to such appliances in Part 8.

The BSS does not specify the type of LPG appliances to be installed but we do recommend the installation of room-sealed LPG appliances suitable for boats. The BSS also strongly recommends the use of competent gas installers to carry out work on boat gas systems.

You can expect that competent gas fitters will follow the relevant installation standards - PD5482-3:2005 and ISO 10239:2008. Both of these standards say to install room-sealed LPG appliances if the appliance will be left unattended.

As well as being an installation standard PD 5482-3 is regarded as a 'maintenance' standard and contained in an Annex it goes on to give guidance on this subject to gas installers.  It says that like for like replacement would be acceptable if it was not possible to install a room sealed equivalent and if a risk assessment determined low risk.  The replacement instantaneous LPG water heater would have to have an input rating of less than 11.6 kW and befitted with a combustion products safety device.

In summary, replacing an instantaneous LPG water heater with a similar appliance is not subject to BSS requirements but unless the competent gas installer considers like for like replacement reasonable after a risk assessment, the customer may find it difficult to find an installer prepared to fit the appliance.   The customer is recommended to explore the potential for a room sealed replacement appliance.