Right !
Builder wants to get his mate ( the installer ) back to fix this . I said yes in the proviso I put photos up here and if it’s still wrong he gets him back again . I’ve explained what I think should be done . 2 tundish . Uvc closed , boiler one open . All pipe work after tundish min 22mm . Why I have to tell them is worrying - but they don’t know . Though apparently “ it’s obvious now the 15mm is wrong “ - he didn’t mention a second tundish ....
Photo soon ; especially for Nick , as he’s a big boy !!!