A quick hammer....

[ToughButterCup]

We've had a new heating system installed. Tickety Boo.

 

Every time we open or close a cold tap quickly, there's a brief knocking sound.

Anything I can do?

[Onoff]

Open the tap slower.

[Jeremy Harris]

Two things. 

 

Firstly, try going around and seeing how well secured the water (not heating) pipes are.  Sometimes it's just poorly secured pipes that don't have enough pipe clips to hold them that makes the noise - this is what we had after the lazy gits who swapped our boiler over and re-ran some of the cold water plumbing.  They had left a long run of pipe in the loft barely secured at all, and it was flopping up and down and making a noise when any tap, or the dishwasher or washing machine, turned off the water.  The fix was just to clip the pipe securely to the ceiling joists.

 

If that fails, then you can try fitting a small expansion tank in the supply.  They make tiny ones that are ideal for this, like this one: https://www.bes.co.uk/mini-expansion-vessel-shock-arrestor-11355

[ToughButterCup]

1 hour ago, JSHarris said:

[...]

They had left a long run of pipe in the loft barely secured at all, and it was flopping up and down and making a noise when any tap, or the dishwasher or washing machine, turned off the water.  The fix was just to clip the pipe securely

[...]

 

My money is on this one.... 

[Jeremy Harris]

12 minutes ago, recoveringacademic said:

 

My money is on this one.... 

 

 

So is mine!