Water hammer

[Taconite5]

Not sure what you mean by the above, its the air end pressure you are checking and setting so losing the water side pressure is correct and the only proper way to check it, what pressure have you set it to with the water side disconnected?.

Hi can you help me make sense of this...

I've fitted a pressure gauge to my system. It reads 4.5Bar initially, but if I open and close the kitchen tap rapidly it goes up to 8bar! It stays there even if I open the kitchen tap fully or close the water meter and run the kitchen tap empty. It only goes down if I run the dishwasher or close the ball valve and loosen the Y piece. I don't get why the pressure doesn't drop down again.....

The red X marks the location of the water hammer, if you open and close the "other taps in house" - is this because of the 8 bar surge?

What do I set the hammer arrestor to?

Does it need another hammer arrestor before the ICG?