Running multilayer to External Boiler

[Bemak]

In the middle of refurbishing an old farmhouse at the moment and am currently working out service routes before the new slab goes in. I'm proposing to locate an external boiler about 20m from the house - the pipework will be 26mm pex pipe (10mm insulation) which will be run inside a 110mm Wavin pipe - all of which will be buried about 600mm below ground level. I appreciate that some element of heat loss will occur along the way - but as we're proposing UFH in the house, the reduced temperature shouldn't affect things too much. Before I lock this in, just wondering if anyone else has done something similar and if so, how has it worked out? Thanks!

 

*update - apologies, I just realized that I posted about this already. Please ignore!*

Edited May 29 by Bemak
repeat post