Jerry Schwartz wrote:

Since having our gas hot water heater replaced, I've noticed that there's a
single "bang" after hot water use. It isn't associated with turning the
water on and off. I think it is thermal, pipe expansion or contraction after
the hot water heater runs to recover.

Is this going to damage anything? In other words, is it worth figuring out
exactly what is banging and where and trying to fix it?


Put your hand on the pipes near the heater when this occurs;
may help find the source.

See if the heater has been equipped with "heat trap"
nipples on top. These have a check valve which
might possibly be to blame (though they usually just click).

Jim