to be clear, the leak is the faucet is allowing water to flow past to the shower head, it's not leaking in the wall.

I have a single valve Hans Grohe shower valve. Hans Grohe

TLDNR - valve was leaking (broken internally) so I replaced it and the new valve does not alway shut off water, and sometimes even if it does shut off water, it will start to drip at the shower head a few hours later.

A month ago, it started not shutting off. Took it apart and found the internal cartridge (part linked above) had cracked and it would not longer seal and shut off the water. The water shut off and mixing (hot/cold) is held inside the gray part of the assembly in the link. There is a metal slide with slots that rotates inside the cartridge and allows hot/cold water to flow. The seals are like the single handle faucet on your bathroom sinks (the small rubber seats with springs).

Delta makes a similar faucet. The two ports go into the wall assembly and it's all held in place with a threaded fitting to set it against the balance valve inside the wall.

I took the whole system apart (except for the in-wall box and pipes) and cleaned the internal brass seats so that the system would seal and not leak inside the wall. It worked fine for about a month.

A few days ago, I turned the water on to take a shower but son called so I shut off the water but it kept coming out of the shower head at a very small flow. Maybe 1-gallon an hour. So I turned it back on, let it run for a few seconds, turned to off and it shut off...but then a bit later it just started dripping. I thought maybe some hard water deposit got into the valve so I took the whole thing apart, cleaned it all out and put it back in.

Same thing is happening again. Every now and then it will just not shut off the water flow (I haven't figured out it if it's hot or cold yet - there are shut off valves in the box so I could figure it out when I get time and it happens again).

Any thoughts on why the cartridge would work most of the time, but sometimes just randomly leak bye?

Also, it's a Home Depot Delta part replacement, not Hans Grohe but it measures the exact same as the part I removed. Some of the reviews basically said the same 'works then doesn't"

Did you lubricate it with a silicone grease before inserting the new valve? Mine (Delta) has rubber gaskets that need lubrication prior to use otherwise what you described happens.

AgResearch said:

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Did you lubricate it with a silicone grease before inserting the new valve? Mine (Delta) has rubber gaskets that need lubrication prior to use otherwise what you described happens.

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I'll pull it apart and try, but not sure exactly where. The seals on that photo (the two ports like things that are white in color) just go into the brass valve body in the wall but don't do anything but seal it to keep it from leaking into the wall.

The actually on/off mechanism is inside the gray part of the cartridge. The on/off is a flat disk with slots in it and as you turn the handle, the slots are exposed to the hot/cold inlets (those two port things) and allow water thru and up to the shower head. Those two ports go to small rubber/spring gaskets that ride on the flat disk. As the disk rotates closed, those rubber gaskets seal against the flat disk and stop the water flow.

I can take the gray part off the white part (it screws apart in like 1/2 turn). I know this b/c that's how the old one failed and I could see the internal mechanism.

Are you saying to put the silicone grease inside?

Each of the white parts have black rubber o-rings and I believe the gray portion has a large one on it. They are easily damaged if not lubricated at installation.

I had this issue with a shower valve in our newly built house. I had to swap out the cartridge immediately after install due to defect or plumber laziness without lubricating.

AgResearch said:

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Each of the white parts have black rubber o-rings and I believe the gray portion has a large one on it. They are easily damaged if not lubricated at installation.

I had this issue with a shower valve in our newly built house. I had to swap out the cartridge immediately after install due to defect or plumber laziness without lubricating.

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OK, I'll try that. I'm just having trouble understanding why those two O-Rings on the white parts would cause a leak at the shower head. All they do is seal the hot/cold at the mixing valve box in the wall from leaking into the wall. They have nothing to do with flow to the shower head.

Any water that is leaking past the rear hot or cold in points would be forced up through the shower head. Those o-rings could have been damaged causing your drip.

Aggietaco said:

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Any water that is leaking past the rear hot or cold in points would be forced up through the shower head. Those o-rings could have been damaged causing your drip.

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Those just seal the cartridge to the valve box and prevent water from leaking into the wall. The cartridge slides into a ~2" diameter fitting and a large screwed fitting holds it against the valve box to seal everything.

The water is always there once you open the stop valves in the wall. If those O-Rings were leaking, I'd have water dripping down the wall into my kitchen.

This video shows how it works. The 1:50 mark he takes it apart.



Maybe I just need to take it apart and put some silicon grease on those internal seals. Also, I adjusted it for as much hot as possible on the valve handle as the wife likes HOT showers. I wonder if it adjusted to far.

It may not be the cause of your leak, but those smaller rear o rings do not prevent water leaking into your wall cavity. If there is water leaking into your valve body from the hot and cold supply, it will be pushed up to your shower head.

If you look at the video you linked, you'll see the two supply inlets and one exit to the shower head. Your mixing valve doesn't have a specific pipe or pathway to the shower head, it just dumps water into the valve body which is forced through the exit to the shower head.

Aggietaco said:

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It may not be the cause of your leak, but those smaller rear o rings do not prevent water leaking into your wall cavity. If there is water leaking into your valve body from the hot and cold supply, it will be pushed up to your shower head.

If you look at the video you linked, you'll see the two supply inlets and one exit to the shower head. Your mixing valve doesn't have a specific pipe or pathway to the shower head, it just dumps water into the valve body which is forced through the exit to the shower head.

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this is where I misunderstood. I thought hot/cold entered the cartridge and then left the cartridge. Which makes no sense as there is only a cold and hot inlet and no outlet from the cartridge. The cartridge just balances how much hot or cold is allowed into the body (left and right holes) and exists to the shower head (top hole).

THANKS!

No problem.

Again, may not be causing your problem, but I would start with replacing those o rings with the spares that likely came with your cartridge, lubing them for re-install, and also adjusting your mixer back down a bit closer to normal to see if your problem goes away. If not, could just be another bad cartridge.

Did not have time to mess with the valve last night, but I think maybe I adjusted it wrong, or it's just bad.

~45m after I took a shower, I was reading and heard it dripping. Not a slow drip, but more like a continuous flow hitting the shower floor. Flip the lever on off a few times, which usually makes it stop but it kept flowing. I could hear the water flowing in the pipes in the wall as it came out of the shower head while the handle was full OFF (it was not leaking in the wall, I could just hear it flowing in the pipes). As I was turning the handle on/off, I heard the water flow stop when I adjust the handle a small amount to ON. So I left it ON a small amount and it stayed off all night and was not dripping this morning (floor was completely dry).

Something else that's odd, when I turn on/off the hot water at my bathroom sink, I can hear a rumble (like water hammer or air in the pipes) at the shower.

Going to stop and get some silicone grease on the way home and mess with it this evening. Fortunately the valves inside the wall work so I don't have to shut the whole house off to work on it.

I know there is something odd with my home piping because whenever the sprinklers run, there is a constant tick-tick-tick-tick in my pipes in the house. It's like there is air trapped somewhere in the pipes. It only makes that noise when the sprinklers run, not anything else in the house though.