New hot water pipes have Smaller Diameter, does this change anything?

[maples89]

My plumber has changed the hot water pipes in the bathroom/kitchen
and they are now slimmer – diameter has been reduced from 30mm
pipes to 22mm and 15mm pipes too. Will there be any difference
to the water pressure because of this or any other noticeable change?

 

[kay-jay]

not if you are on a combi boiler. if hot water is gravity then flow rate will be affected and not pressure. if you have the diameters correct then 22 will be adequate for most domestic premises