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Water Hammering? Noise in wall after changing shower cartridge.

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Mar 09, 2014, 12:13 PM
Water Hammering? Noise in wall after changing shower cartridge.
Hello to any that might help,

I just changed the posi-temp cartridge in my shower because it was leaking. It's a Moen Chantille single handle shower that controls the shower and faucet in the tub. It turns on counterclockwise to control cold to hot water flow and clockwise to shut off. It was the original cartridge that was about 15 years old. So needless to say it was pretty well stuck in the housing. I really had to man handle it to get it out. Now after I changed it I am getting a knocking in the wall when I use the hot water from any faucet and when the washing machine is in use. The washing machine only uses cold water. After some internet research I have identified a problem know as water hammering. It seems that if the plumbing was not installed with enough clearance through the beams or not fastened securely to the beams when they were roughed in the expanding of the copper tubing from the hot water causes it expand and contract, possibly causing this noise or the pressure of the water flowing and then stopping will also cause it.

Any ideas would be helpful. I would really hate to have to cut a hole in the wall to clear this problem up. The banging is really starting to piss me off.

Mar 09, 2014, 12:58 PM
If it were me, I'd shut off the water where it enters the house, then open all faucets and let the water drain out and let the air go in, including garden spigots. Then shut off valves, then turn the water back on, then open valves slowly. Easy enough to do, it might solve the problem, no cost, no problem if it doesn't solve the problem

They make it look so easy on tv, don't they
Mar 09, 2014, 01:33 PM
Thanks, tried that twice. It did not solve the problem.
Mar 09, 2014, 01:48 PM
What I don't understand is I had no problems with noise before I changed the cartridge. Could it just be air in the pipes?
Mar 09, 2014, 03:14 PM
I had a similar problem and found that the pipes behind the washing machine were the cause of the banging. I also didn't want to cut into the wall to secure the pipes, then have to patch it. What I did was drill a small hole near where the noise was the worst, and sprayed some expanding foam into the area. After it set up, no more noise and a cheap easy fix did the job
Mar 10, 2014, 11:41 PM
Could it just be air in the pipes?

Yup, it's air. You need to re-establish an air cushion.

Shut water at the meter. Shut all valves including washer and toilets. Open the cold water faucet of the lowest sink. Now go upstairs and open all faucets. After the lowest faucet stops dripping, shut all faucets.

Open valve at meter. Slowly open valve for toilets. Be prepared to hear noises and pops. Turn on water at every faucet until there's no noise. That should do it.

Shouldn't need to bother with hot water, but if necessary do hot too on second go round.


Tile 4 You llc - Troy, MI
Kerdi shower specialist - Ditra installs - Product-Method suitability consultation. I have NEVER made a mistake, I thought I did once...........but I was wrong!
Mar 11, 2014, 08:13 AM
Thanks to all for the responses. I had actually tried this already JazMan. Now that I think of it I didn't on/off the toilet or the outside faucets. I will have to try it again. Nothing to lose. I called Moen yesterday and explained the problem just to see if they could help. I explained I used an after market cartridge bought at Home Depot and asked if maybe this was a problem. She didn't think so but thought I might have left some gasket debris in the line from the old cartridge. I did chew up the old cartridge getting it out and had to pull out pieces of the old gaskets from the hot and cold ports inside the housing. Maybe some is left. A positive thing about calling Moen is the woman I spoke with is sending me a new $75.00 Moen cartridge for free. Smile I am going to change it out and try to see if air in the lines is the problem.
Mar 15, 2014, 02:02 PM
Thanks to all. Finally solved the problem. Turned out to be the after market Danco cartridge I bought from Home Depot. Received the new cartridge in the mail from Moen, installed it and the noise went away. Followed JazMan's advice and bled the lines of air, and there was a lot of air in the lines, and bingo, no more knocking. Guess the rule of thumb from now on is no more after market products when it comes to this kind of repair.