[A Good Plumber]

I've been doing the service work at a nearby three story office building.
The building was built about 8 years ago and when the restrooms were plumbed, water hammer arrestors were installed in all the required locations.
Since then, every time a toilet or urinal flush valve is activated, the pipes hammer. The arrestors are sized correctly and were changed shortly after the building was done.

I recently went to a seminar for Zurn and learned that if you install a triple filtering diaphragm kit, either in a Sloan or a Zurn flush valve, the hammering will go away.
Needing 30 flush kits and not so sure this idea would work, I talked the Rep into giving the kits to me If it didn't eliminate the hammering.

Eight years of hammering is gone!

 

[Bill]

You said it was a triple filter one. What was it with the old ones causing the hammering? Glad the new ones worked.

 

[A Good Plumber]

The flush valve diaphragm normally installed in a Sloan Royal or Regal flush valve is an A-36-A or a A-42-A in a urinal or WC FV. I think Zurn is the only manufacturer of the triple filtered diaphragm. This diaphragm allows the valve to close more slowly, thus eliminating water hammer.

If you ever find a building experiencing water hammer at the flush valves, try the Triple filtering diaphragm and the hammering will go away.

 

[Plumberman]

Old ball cock fill valves in gravity toliets will do it too.... Ive got to change a bunch of them in a house because the hammering is keeping the HO up all night....