Noisy mains water pipe after changes

[Chris Male]

The layout of our mains water pipework was recently changed, to move the stopcock on the incoming supply to a downstairs cupboard.

This joins a 22mm pipe that feeds upstairs cold water, and to the boiler on an unvented system. There is a tee off this 22mm pipe into a 15mm pipe which feeds the downstairs cold main.

Since the change in layout, whenever the downstairs toilet is flushed, the whole of the cold pipework makes a loud rushing noise. Is this because of the 22mm to 15mm tee? Or is the pressure to the cistern now too high, as it’s so close to the mains supply?Can anything be done about it?

 

[dilalio]

Make sure the wc inlet valve has a restrictor for mains fed water in it.
When new, they usually come with both tank and mains fed options.
If it's not been used, you probably won't have it stored somewhere, so just get a new inlet/fill valve on the wc.
Get a fluidmaster.

 

[Chris Male]

Many thanks. I only fitted a new inlet valve about 5 months ago, but don't remember it coming with the main's fed restrictor? I'll have a chat with my man at Screwfix.

 

[CBW]

Many thanks. I only fitted a new inlet valve about 5 months ago, but don't remember it coming with the main's fed restrictor? I'll have a chat with my man at Screwfix.

Do you know which brand? Or if usnsure upload a photo?

 

[Chris Male]

It’s a Fluidmaster bottom-entry (fnah fnah) 1-2” full valve.