I want to install a direct un-vented hot water cylinder in a flat. The install instructions call for 22mm diameter water supply line, the main riser supply to the building is 22m and then reduces to 15mm before the stop valve. Do i need to isolate the main riser into the building in order to replace the 15mm stop valve with 22mm or can I step up the pipe diameter back to 22m after the
15mm stop valve without affecting the performance of the cylinder.- posted
6 years ago