plastic hot water return help

[voivod]

Have been asked to price a job where hot water outlets are 20/30m from cylinder. It's also in concrete screed.
Would have used plastic pipe in tube but need hot water return.
Usually thas not allowed but have also been told by manufacturers that can use their 5 layer plastic pipe.
Can't put it in wooden faced ducts as there will be underfloor heating on top.
Any ideas Gentlemen/ ladies ?

 

[Gray0689]

Why can't you just lag it in armaflex and put in screed under insulation before underfloor goes in
Tee in above ground at the furthest whb in A multi layered pipe

 

[Ch4 plumbing]

Or run it inside this and lag, then any problems with the pipe pull the entire length out and replace.

 

[voivod]

have been looking at the soft copper option in duct

 

[voivod]

Seems mad that they do plastic hot water returns in europe butt not here?
Is there no legionella there? or do they just keep hw above 55 deg??