Any ideas what this is

[ShaunCorbs]

Waste heat recovery unit supposed to take the heat out of bath or shower waste water and use it to preheat the incoming main

and have a legionella risk dont think so

 

[Destroyer2813]

and have a legionella risk dont think so

Just googled domestic heat recovery and shows units for that purpose

 

[Rckape]

I've never seen one of those before! Just had a hunt around on google and there are plenty of companies making them, costing around £500!!!

They seem to be either a main sweater jacket around the inner waste pipe or a copper coil over the outside of a waste pipe so no interconnection with waste water.

It's an interesting point with regard to legionella. I think the risk is slim though. The worst case is if the shower is tuned to cold after a hot shower then there's a possibility of getting legionella prone water, but the chances of it occurring between the Hex and the outlet are slim.

I'm assuming that there would have to be some double check valves to prevent warmed water flow to other cold outlets?

 

[Rckape]

 

[Destroyer2813]

That's what I found too but couldn't post from my phone

 

[stevetheplumber]

no doubt on paper it increases the energy efficencey of the building and the builder can omit something that would actually work but is more exspensive
i watched a grand design recently where to make up for the huge heat loss from massive windows they added loads of insulation else where