Jg speedfit isolation valve clicking with water pressure change

[DanBow]

Hi, I have recently installed jg speed fit isolation valves on the pipe work for my shower. One of the valves is clicking when the sink taps are turned on or off. I have never really had any issues with hammering however I think my pressure is quite high. Is this something to worry about? ShoulD I replace the valve? Is it worth having a hammer arrester?
Thanks for your help.
Additional: I have used speedfit quite a lot and I'm sure I have fully inserted and used inserts on the plastic pipe (plastic in copper out). Only the hot valve is clicking but it happens when either sink tap or toilet is used. These are full bore 15mm valves (the grey ones with the steel screws). I have a combination boiler and main pressure hot/cold. Clicking stops if isolator turned off (must be copper pipe out clicking).

 

[DH6]

Expansion of the hot water pipe across joists??

 

[DanBow]

I don't think so, the plastic pipe comes horizontally through the joists and using a coldform 90deg bend former it comes vertically up through the floor and then into the valve. If the valve is off the clicking stops.

 

[DanBow]

There is a similar clicking (but very quiet) on another jg valve which runs the the sink hot tap. This is why I was considering the arrestor. Combination boiler was only fitted recently so may be related?

 

[DanBow]

Managed to fix the problem. Just need to shorten one of the pipes slightly.