jaynews wrote:
you may have existing water hammer chambers already installed in your
house that simply are flooded. this website discusses that and how to
drain them at:
http://www.naturalhandyman.com/iip/infplumb/infwatham.shtm

Tried that. Did not help.

Called Fluidmaster. They're sending me the "Whisper valve" version which
has restricted flow. Is there any chance the Whisper model WON"T solve the
problem? If so, then maybe I should just go ahead and buy the a Korky
QuietFill though. I'd hate to spend the time installing the Whisper valve
only to find I STILL get the thunk.

Listen, the flipping part is $10 and it'll take you a half hour to swap
out if you take a coffee break in the middle. You're dicking around on
a newsgroup, people have given you all sorts of good advice, and you're
still asking about the other valve. What are you looking for? A
guaranty? Okay, I solemnly swear that the Korky Quietfill will solve
all your problems. Just do it, fer cryin' out loud!

R