Have you had this fixed yet?
If not adjust your pressure vessel to 0.2bar below your dynamic pressure of your cold supply to the cylinder.
Most of the time those pressure vessels come charged to as much as 3 bar.
At a guess 1Bar would probably sort it but the proper way to adjust it is as per above.
99% if the time noise problems like this is a pressure vessel problem I’ve fixed countless systems like this.
Anyway hope this helps 👍
step by step,
1) check dynamic pressure on cold supply to the cylinder
2)isolate the cold supply to the cylinder and run off the pressure by opening a hot tap
3)check the pressure on the pressure vessel through the Schrader valve
4)Reduce the pressure in the pressure vessel to 0.2 Bar below the dynamic pressure by depressing the pin in the Schrader valve
5)Open the cold supply back up and run the hot taps to remove air from the system
6) turn the hot water on for an hr or until the cylinder is suitably heated up
7) open hot tap with crossed finger and hopefully steps 1-6 have to been a waste of time 😂👍
good luck but I’m optimistic
