I think this question refers to water hammer or hydraulic shock but am not sure, If this is correct then it can be avoided by using sprin-loaded check valves, minimized by installing air filled extensions or air chambers, minimuized by installing a shock absorber near the service entrance.

I cannot find 'air hammer' information anywhere.

Thanks.

T

Hello T-it sounds like you're describing "water hammer". You can buy air chambers, or fabricate your own setup, to alleviate this condition by creating an air bubble in the piping. Since air in the chamber can compress, the shock waves in the flowing water can bounce back against this air cushion and avoid the unpleasant and potentially damaging banging you hear. I've also seen folks on this site recommending a pressure regulator on the incoming water supply line, which controls the rate of water flow and acts as a damper to prevent water hammer. Hopefully Tom (Speedball) will put his professional information out here and give you a better understanding and solution. Good luck! Dave

Myoldhouse gave a very good description of water hammer. In the 60's we were mandated to install air chambers,(see image) in the wall on all lavatory and kitchen sink stubouts. These air chambers acted as shock absorbers to cushion the shock of the sudden stop ow water against a fitting. These air chambers are preferable to spring loaded check valves because they have no moving parts to go bad. However, periodically they load up with condensate and must be drained and recharged with air. This is a job the homeowner with little plumbing skills can do for himself saving himself the cost of a plumber. Regards, Tom