How does EN1717 effect WWHR?

The standard EN1717, originally created for water tanks and not for WWHR (Waste Water Heat Recovery) specifically, is focused on preventing the contamination of freshwater by greywater (Level 5) as well as the backflow of greywater and gases.

Contamination can result from damage to the pipe wall, thus opening a channel for contact between grey and fresh water. With our vertical units, this is very unlikely to happen as they are made from stainless steel, not copper, which has far superior corrosion resistance, and the greywater circuit is not permanent or under any form of pressure.

However, as it is installed as a single-walled pipe, EN1717 calls for the use of a siphon/trap to prevent the rise of gases to the WWHR.

We believe that this should also be mandatory for a doublewalled pipe, and that EN1717 needs to be updated for the WWHR system.

We are already in contact with British Standard Institute (BSI) with the aim of having them validate the legitimacy of our point about the unsuitability of the EN1717 standard for the WWHR system.

More updates will be released as they become available.