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dwieder
Water hammer in remodeled shower
dwieder

I need some help from some experts.
We recently had our bathroom remodeled including a new shower with a single valve. We started noticing some water hammer coming from the shower whenever the toilet shut off after flushing, or the bathroom sink was turned off and on. This happens when the shower is turned off. At first I thought it was a defective cartridge, so we replaced that. We also had water hammer arrestors placed on the sink pipes as well as the shower pipes. Noise was still there.

Recently, I discovered that if I shut off the hot or the cold water at the shower valve (there is a shutoff screw for both the hot and the cold water at the shower valve, for maintenance), the knocking stops.

Does anyone have any idea what the problem could be and how to go about trying to fix this? I don't want to have to put the wood trim off from outside the house unless I'm sure I can fix this problem.

Any help or comment would be appreciated.

Thanks.

johnjh2o
Re: Water hammer in remodeled shower
johnjh2o

Are you on City water? Your water pressure may be to high or your pressure reducing valve may need to be replaced or serviced.

dwieder
Re: Water hammer in remodeled shower
dwieder

Yes, we are on city water, and the pressure is good. The plumber already checked that out. The strange thing is that when either the hot or cold valve is shutoff at the shower, the knocking goes away, even though the shower is not being used.
Any other thoughts?

dj1
Re: Water hammer in remodeled shower
dj1

You kind of isolated the problem to the new single handle valve body. I would replace it and see if there's any improvement.

dwieder
Re: Water hammer in remodeled shower
dwieder

Thanks for the confirmation. I'm just trying to narrow what I can down before I get the plumber out here to take a look. It seems like it's related to the single lever shower valve, but there's not much to it except for the cartridge that I replaced once already. Does it seem possible that two cartridges are defective or that the actual valve could be bad?

johnjh2o
Re: Water hammer in remodeled shower
johnjh2o

What make valve do you have? You also stated the plumber checked the water pressure did he tell you what it was? And how did he check it?

dwieder
Re: Water hammer in remodeled shower
dwieder

The valve is a Calfaucet. The rough in valve is the PBS-R unit. The plumber checked the pressure right next to the pressure regulator unit where the water comes into the house. The pressure is about 60. He increased it to 80 when we checked this previously because I thought the water pressure was too low. The increase in pressure didn't change the knock and he lowered it back down. The plumber was out there to look at the pressure regulator, not the knock. I had thought the pressure was in the low 40's but it wasn't. I'm trying to run down all possible solutions before getting the plumber back out after I open up the outside of the wall. So that is what I'm going to do next unless there are other ideas.

bill
Re: Water hammer in remodeled shower
bill

1)Are all the water pipes properly secured ?
2) I have found that some water hammer arrestors fail. I do not like them i prefer the way we did it back in the day.
This is how it was done A pipe went up a wall until it came to a fixture, a tee was installed and the side of the tee went to serve that fixture. the pipe then continued up for 24 inches then a cap was installed. This air chamber acted like a huge shock absorber. The only trouble with this was that in time the air was dissolved by the water. What you woulds do it turn off all the water and open each faucet, the close each faucet and open up the water. recharging all the air chambers. you might do this every couple of years.

dwieder
Re: Water hammer in remodeled shower
dwieder

My problem was resolved. Getting on the phone with a technical guy from CalFaucets, he told me the most likely problem is the pressure is different for the hot and cold water coming into the shower valve. He told me to play with the shutoff screws at the shower valve to see if the problem goes away. I did that and by turning down the hot a little bit, 1-2 turns, everything seems fine now. The tech told me this is about the 4th case he has ever heard about, so it's rare. Bottom line is, everything seems good now. I appreciate the comments from everyone.:)

Re: Water hammer in remodeled shower
dwieder wrote:

My problem was resolved. Getting on the phone with a technical guy from CalFaucets, he told me the most likely problem is the pressure is different for the hot and cold water coming into the shower valve. He told me to play with the shutoff screws at the shower valve to see if the problem goes away. I did that and by turning down the hot a little bit, 1-2 turns, everything seems fine now. The tech told me this is about the 4th case he has ever heard about, so it's rare. Bottom line is, everything seems good now. I appreciate the comments from everyone.:)

I haven't heard about such an issue.
If you didn't change your water pipes diameter during the renovation process, then pressure shouldn't change as well.

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