Loud jackhammer / vibration when faucets are open

[Schroedad]

We recently had our home completely re-plumbed starting where the main 3/4" copper line enters the house in the basement. The plumbing is a branched Wirsbo system. There is a PRV right after the main shut-off valve inside the basement.

When we turn on various combinations of faucets, a very loud jackhammering starts in the plumbing. It appears to be coming either from the PRV or the line coming into the house. The pipe vibrates most violently between where it enters the basement and the hot water heater. Squeezing or holding it tight against the rafters doesn't help. The PRV often makes a "thup, thup, thup" sound when this is happening. The sound stops as soon as we shut off all the water faucets. It's also sometimes hard to consistently reproduce. It almost always happens every time we turn both shower valves on (but not always!) We can get it to start by turning on different combinations of sinks or showers. Doesn't seem isolated to any one faucet.

The only thing I have found that makes the sound go away completely is opening the PRV all the way (highest pressure setting). This led me to think the PRV was bad so today the plumbers came back and replaced it. Unfortunately this didn't help at all.

I also tried shutting off supply to the toilets and various faucets wondering if there's a loose washer or something- no affect.
I made sure all shut-off valves are completely open
I attempted to remove all air from the system by shutting off main supply, opening all faucets and spigots, then turned supply back on, closing the valves one-by-one (trying to remove all air from the system). This didn't help.
I shut off both supply and hot water exit valves from hot water heater to isolate that from the system. This didn't help.

The plumbers are also out of ideas and have spoken with a few other plumbers in the area. Their only thought is to dig up the supply line between the house and meter -- perhaps there is a kink in the line? This would be a major expense for us as we had just finished landscaping and the meter is about 50 yards from the house entrance. Plus there's no guarantee this is the problem.

Any other ideas of what we might try? In the meantime I have the PRV set all the way open, which I know isn't great for our fixtures. But this seems better than having the pipes vibrate violently every time we turn the water on. Thanks in advance!

 

[Dj2]

You want to solve this asap.
I would call the water company.
1. Ask them what the street pressure is. Also measure the pressure with the PRV at max position.
2. Ask them if this problem occurs at other locations.
3. Ask them for ideas. See what they say.
4. Ask your neighbors if they experience the same condition.
5. When you replaced the PRV, did you get the same brand? If yes, try another brand.

Note: Sometimes calling customer service will not get you the right answers. Talking to the water company field techs would be more productive. They are located in the company's yards, not in the company's offices.
I have been to my water supplier yard near me a few times on various issues, and got help directly from friendly techs every time.

 

[Sponsor]

 

[Reach4]

The only thing I have found that makes the sound go away completely is opening the PRV all the way (highest pressure setting).

What pressure do you measure then?

What make and model is this PRV, not that I know which ones might tend toward unstable behavior.

 

[Schroedad]

With the PRV set at max (screw tightened all the way down), I'm reading 110psi at two different hose bibs. There is 3/4" PEX running to all our hose bibs.

The model # of the PRV is EB-45. I think it's this one: http://bit.ly/2iBISRu. Yes, they used the same brand/model when replacing.

I just turned the PRV back down to where pressure at the hose bib is reading 55psi. Now we can't get the pipes to jackhammer. Spent about 15 minutes closing and opening various combinations of faucets and no noise. Last night it happened almost every time we turned water on. This has happened before where suddenly it's working fine and then the next day we have problems again. Could it be somehow tied to when our neighbors are running water?

I will call the city about the meter. I was hoping we could first create the jackhammering noise and then go look inside the meter to see if it's also vibrating. Below is a picture of the PRV and water supply entering the basement.

 

[hj]

The "thump, thump, thump" is usually the sound of the water meter operating.

 

[Terry]

Sent by a reader:
little known cause of water hammer
I am not a professional tradesman but with the valuable help of the internet I have been able to repair and replace lots of parts and components around the house and of my auto. So I am posting and sending this to some plumbing and DIY sites and forums as my contribution in thanks, particularly since I have not seen this situation described on any these sites. This text and info is available for use free of charge and does not become proprietary information of any recipient.

I was struggling with a water hammer problem in my house pipes over the last couple of years and could not find a solution which worked. Finally a plumbing shop manager told me that he recently had a customer with the same issue and after many attempted solutions they finally resolved it by…changing the pressure equalising cartridge on his shower fixture. He told me the cartridge can become encrusted with mineral deposits which causes to operate incorrectly. He slowly shook a new cartridge back and forth to let me hear a distinct mechanical toggle sound. A maloperating toggle can cause pressure waves and water hammer elsewhere in the system.
I changed the cartridge and my water hammer problem disappeared. The old (5 yrs) cartridge I pulled out was not making the mechanical toggling sound when moved back and forth and was effectively encrusted with white mineral deposits.
Important to note that the pipe vibration we were experiencing was located principally at a sink faucet near the shower but not at the shower faucet itself.
Some more information which may be helpful:
We had our bathroom renovated 5 years ago: New bath, sink and shower all with new fixtures and new toilet. The new sink and tub taps are quarter turn ceramic.
First additional item: Early on after we renovated, when turning of the sink or tub taps or when the toilet stopped filling there was a slight pipe shaking sound from the wall behind the shower fixture. I thought the renovation contractor must have not adequately braced the pipes in this area. I only realised after the cartridge change that this sound had disappeared during the time we had strong water hammer and has now returned – because it’s not the pipes slightly moving; it’s the sound of the mechanical toggle within the flow equalising cartridge (this will toggle on pressure changes even when the shower is off). Close listening right over the cartridge has confirmed this. It’s a sound I can easily live with considering the benefit of a pressure equalising shower fixture and now that I know it’s not harmful to the plumbing system.
The water hammer only started a few years after the renovation (when the cartridge started maloperating I guess) - we started having leaky sink faucets and then we would get very strong repetitive water hammer often in situations when multiple taps or valves where turned on in the house. Often the vibrations (again always strongest at the sink near the shower) would not stop on their own and we would hurry to turn off any taps to stop it. Also sometimes one of the sink faucets would turn on and flow on its own - I suspect following hammer caused by a valve closing elsewhere. I changed the quarter turn ceramic valves but the leaking reappeared after a few months. I suspect these were caused by the vibrations from the water hammer. Time will tell on this one.
I hope this info helps someone our there as much as other posts have helped me DImY.
Peter G.

 

[FullySprinklered]

If it's none of the above, then it might be a defective vacuum breaker on an outside spigot.
Also might be a vacuum breaker on a defective (leaky) spigot.

 

[Schroedad]

Thanks for all the ideas. After my initial post it seemed the hammering went away. Not a sound for over a week despite using various combinations of faucets frequently. Then, last night it happened once again when we flushed both toilets at the same time (something we had done several times with no issue). But it only happened once and stopped as soon as the toilets stopped filling. I tried to reproduce by flushing both toilets several times, but nothing.

I'm beginning to wonder if there is just air in the line somewhere. A defective vacuum breaker might explain that. Although, seems unlikely -- all our fixtures and spigots are brand new.

 

[Schroedad]

Thought I'd follow up on this. Plumber came and replaced the PRV over 2 months ago. Strangely, the jackhammering happened once more the next day, but has not happened again since (now 2+ months later). I'm guessing there was just some air in the lines after installing the new PRV but that is what fixed the problem.