Shower/Tub Handle Knocks

My bath/shower handle (SYMMONS Model A) knocks loudly when I turn it off with the diverter set to the bath. If I leave the diverter set to shower, it does not knock when I turn it off. My questions are:
Is there some part speccifically that probably needs to be replaced, or should the whole handle be replaced? I do not have access to the plumbing in the wall. Can the issue be repaired through the handle? I have a shower hose and spray attachment installed. The SYMMONS web site states it should not be installed due to back pressure issues. Could this be a reason for my problem?
Any help will be appreciated.
Mark M.
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On 21 Sep, 12:11, snipped-for-privacy@sbcglobal.net wrote:

It sounds like water hammer or a loose pipe. Hold the bath spigot when you turn the water off and see if it moves. If it does something is loose and is banging against something else.
Another suggestion would be remove the shower hose and spray attachment to see if that's the problem. The manufacturer said don't use it...you're having a problem...so let's take the first logical step and see if removing it helps.
Of course, even easier than that might be to call SYMMONS and ask them what the specific problems could occur if a shower hose and spray attachment were used. Don't accept "back pressure issues" as the answer - find someone who will tell you exactly what the "back pressure issues" will do to the system.
Finally (or first) you could try this:
Close the main water shutoff. Open all the faucets you can and flush the toilets to drain the entire system. Open the main shutoff. Close the faucets, starting at the farthest/highest one and working your way down and towards the main shutoff.
If you have any water hammer buffers built into your system, this might refill them with air and eliminate the problem.
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I held the bath spigot and it did not even vibrate when the knock occurred
I removed the spray attachment and the knock still occurs with the diverter set to bath only.
I actually had a water hammer installed originally when I bought the home 8 months ago. Then I realized the knocking only came from the tub (while the diverter is set to tub - not shower). No other item in the home creates even a small knock.
I'll call SYMMONS on Monday.
Thanks for your suggestions. Mark M.
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