Hammer arrestors

[bsr]

I have started getting water hammer in the cold system. We've isolated the banging to a general area but can't find the specific location - it may be in a stud wall.

I've decided to try and fit an arrestor. There seem to be two types - mechanical ones like sioux that use an air-sprung piston, and mini-expansion vessels like Altecnic that use a water/air diaphragm.

Any suggestions on which to use and the advantages of each type?

Regards