Noisy Mains When Toilet is Flushed after New Central Heating System Installed

[crof]

I have recently had a new central heating system installed (boiler, radiators etc.) but since then when the toilet is flushed the mains seems to create quite a racket.

The sound of the actual cistern refilling is noisy but not really a problem. The problem is that the pipes are in a bedroom cupboard which create a really loud 'whooshing' noise which is not great when people are trying to sleep.

Does anybody have any advice on how to fix this? My only idea so far is to wrap something around the pipes to try and dampen the noise.

Thanks in advance.

[lets have a look]

could be that they have opened the stop tap fully,try turning it down to reduce the pressure,what about when you open a cold tap does that make a whoosing noise,might need a new ballvalve in the wc cistern