Unlike an expansion tank which absorbs water above the system PSI like 50 psi, the hammer arrestor has a chamber whose back is gas filled that absorbs the water back pressure and the gas pushes the chamber slider back to the original position. The arrestor chamber is not held by your plumbing psi but by filled gas behind the chamber slider that is always pushing back to the original position.
How do you charge them? What pressure do you pump it to and is this with mains pressurised or not
Unlike an expansion tank which absorbs water above the system PSI like 50 psi, the hammer arrestor has a chamber whose back is gas filled that absorbs the water back pressure and the gas pushes the chamber slider back to the original position. The arrestor chamber is not held by your plumbing psi but by filled gas behind the chamber slider that is always pushing back to the original position.