I am fitting a new Mira Discovery thermostatic mixer shower in the bathroom.
The hot water comes from the combination boiler.
The pipe size which connects to the valve body is 15mm. The existing hot water supply pipe under the floor boards is 22mm.
Do I need to change the 22mm pipe under the floor boards to 15mm?
Will this give me a different flow rate between the hot and cold when it gets to the shower?