Hi, Hoping you can help. Have a very loud and visible vibration of the water pipes while a basement level toilet is filling. This problem recently started, about the same time as a hot water heater was replaced by plumber, which led to the Pressure Reducing Valve being replaced by me (not a plumber), replaced the fill valve, and started up the sprinkler system for the season.
So far I've tried:
1) found one loose clamp on the pipes by the WH and PRV, secured it
2) drained the whole house (shutoff main, shut off water to HW, opened all faucets and flushed toilets, starting at the lowest level. Including the outside spigots and sprinkler drain. Turned on main, waited for no air sounds and started turning off faucets starting at the lowest level finishing on top floor. Turned on water to WH)
3) pressure is about 50, drops to 20-25 while toilet fills
There doesn't seem to be any hammering sound at the closing of the valve, but do hear like a 'whoosh whoosh' before the vibrations begin - these continue very loudly till the fill completes. What else should I be trying before calling in another plumber? Your time and feed back is appreciated. Thank you!

Remove the top of the tank and flush the tank completely. As the water fills... and the chatter starts... place your finger lightly on the top of the fill valve... if you feel the chatter put a little pressure on the valve plunger but don't stop the water flow.

If the chatter stops... you just might have a defective fill valve

Also, have you tried opening and closing the tank shutoff coming out of the wall?

What happens when the sprinkler is turned on?

Does the sweat joints on the new HWH (hot water heater) look clean & smooth? If not, that could be a sign that your plumber isn't as good as you or he thinks. Also... try opening and closing the main water valve either before or after your meter. He might have damaged one or both of those valves while replacing your HWH.

Good luck!

Since you had the noise and then replaced the fill valve and still have the noise then my next guess would be to look at the shut off valve at the toilet... may have washer chatter.

Here, shut the valve and then open it all the way and see if the noise is still present. If the noise is still present shut off the main water supply and disassemble the shut off valve at the toilet to inspect the washer... see if the washer is loose or chipped in some way.

Check that and report back...

Mark

Thought the problem was fixed and was out of town for a couple weeks. Problem is back as of yesterday. Thought it was fixed when the PRV was taken off and put back on making sure the "floating" washer stayed in place. Also double checked the water line coming into the toilet that had the fill kit replaced. Seems the hammering only occurs when the valve to the sprinkler system is open. Checked for leaks around the poppit/bonnet and see nothing unusual. There isn't hammering when the system runs, only when flushing toilets...

Thought the problem was fixed and was out of town for a couple weeks. Problem is back as of yesterday. Thought it was fixed when the PRV was taken off and put back on making sure the "floating" washer stayed in place. Also double checked the water line coming into the toilet that had the fill kit replaced. Seems the hammering only occurs when the valve to the sprinkler system is open. Checked for leaks around the poppit/bonnet and see nothing unusual. There isn't hammering when the system runs, only when flushing toilets...

It seems to me it may be a good idea to have a water hammer arrester installed some where in the line.They can be bought at the Home Depot etc

the hammering only occurs when the valve to the sprinkler system is open How old is your house and what material are the pipes? Since turning on the sprinklers lowers the pressure could it be the problem is and that the PRV valve? Have you checked the pressure valve or vibration? Let me know Tom

How old is your house and what material are the pipes? Since turning on the sprinklers lowers the pressure could it be the problem is and that the PRV valve? Have you checked the pressure valve or vibration? Let me know Tom

House was built in 2000, copper pipes. Home PRV steady at 60 (it's after the sprinkler line), Can't test the city PRV value - but does have a whistling/whoosh sound.