Andrew wrote:
On 20/05/2017 17:44, ChrisK wrote:
There is a noticable issue with HW water flow rate upstairs &
interaction between showers & filling the bath is a bit slow. This is
probably down to re-using the original 15mm pipe work. It would have
been better to have replaced this with 22mm.

If your mains pressure and flow rate are adequate then 15mm should be
fine. Sounds like you have another problem somewhere.

Probably not, it is quite a tortuous route the 15mm feed follows to join
the upstairs HW pipework which is all 22mm. Not bad enough to do
anything about it as it would involve taking up a lot of flooring.

CK