Help!!! Knocking Pipes in Shower!!! Only when handle in in the middle!!!

[HomeOwnerFL]

We added a bathroom on our home about 2 years ago.. We had some problems with banging pipes in our shower...

When the single handle shower valve is in the six o-clock position (warm) the water pipes chatter loudly (loud banging sound), if the handle is moved slightly (hotter or colder) the noises stop.

The shower wall is tiled and it’s an American standard fixture set.

The plumber came out and installed a vent of some sort on the cold water line underneath the sink to help alleviate pressure. I thought it was odd that the plumber put it on the sink when the tub was the problem. Anyway, I think it worked fine because the noise stopped for a few weeks... But came back!

It got to the point that if we didn't pull out the handle all the way, it doesn't bang... It only bangs with the handle all the way out... So we lived with it...

Now, I need to fix it. A plumber came out today and said it is probably the cartridge and he doesn't think it's "water hammer"...

Do you think it's as simple as replacing the cartridge?

Any advice? I've noticed, if I have the sink on in the bathroom at the same time as the shower, it doesn't bang... I need help please!!!!

 

[Kingsotall]

The cartridge but more percisely a washer. But it does sound like a balance spool problem when water is flowing through both ports (of the cartridge).

 

[Sponsor]

 

[HomeOwnerFL]

I should add that it only happens when I pull the handle all the way out (in the middle), if I pull it half-way, it's fine...

By the way, I also should add that I drained the plumbing system last night so the air chamber could be released (read it online) and it went away for the evening. This morning, I could feel it gradually coming back.

Thanks!

 

[hj]

noise

It has nothing to do with the air chamber, but there are many places it could occur. In my house it is caused by the "after market" circulator system as water flows through it faster than it can handle it. Reducing the flow, either by reducing the temperature or volume stops it. Until you know EXACTLY what is causing it, changing the core or anything else will just be a guess and could be a waste of time and money.

 

[HomeOwnerFL]

So, what's the easiest way to diagnose the problem? It only happens in that bathroom room and their are ball valves on the outside? Could that be the problem? Would installing another air chamber on the hotwater side work as well?

Look forward to your replies! Thanks!

 

[hj]

noise

Air chambers would have absolutely no effect one way or the other on the noise. When they work it is only to stop the noise when a faucet or valve closes very rapidly, not while water is running. First you find out WHY the sound is happening, and then you can work on a solution, if there is one.

 

[HomeOwnerFL]

First you find out WHY the sound is happening, and then you can work on a solution, if there is one.

So, are you saying that there might not be a solution? Not sure I like the sound of that.

 

[Jadnashua]

There's a solution...just hard to say for sure. Vibrations during water flow are caused by something loose. With a traditional faucet, that is often a washer. WIth a cartridge, a dislodged O-ring might cause it. If the pipes aren't anchored well, you might get some banging when you turn the valve off (which is where a water hammer arrestor might help). Air chambers don't work for long because they quickly fill up with water, the air being absorbed by the flow.

If you have a shower head that is designed to pulse, the changes in flow could cause problems.

All new valves have built-in anti-scald technology. The most common type is a pressure balanced valve. If you have a radiacal difference in pressure between the hot and cold, that could give you some grief. This could be caused by a restricted flow from the water heater, or somewhere in-line, especially if you used any galvanized iron piping - that can often end up nearly full of rust scale.

Try removing the shower head and running the flow without restrictions and let us know if it runs quietly or not. Check the total flow when you run it cold verses hot. Many valves, in addition to the pressure balance valve, have a maximum heat adjustment, so you may not get pure hot.

 

[HomeOwnerFL]

Try removing the shower head and running the flow without restrictions and let us know if it runs quietly or not. Check the total flow when you run it cold verses hot. Many valves, in addition to the pressure balance valve, have a maximum heat adjustment, so you may not get pure hot.

Thanks Jad!

It's not only the shower... The problem actually occurs with shower and tub...

There is a slight difference between hot and cold but not much...

I had another plumber out today and he suggested the cartridge as well... He said if it's not that, then it's the valve, which I'll have to cut a whole in the drywall behind to replace that...

 

[jonesn84]

Hi Jad -

I am having the EXACT same problem with the stuttering water set anywhere in between full hot and full cold. I updated fixtures a little while ago to a Price Pfister "Sedona" unit and right after installing it leaked in the "off" position. I contacted the company and they send out a replacement cartridge. That one leaked as well. They had me send back the entire valve assembly, and sent me a new one (with 3rd cartridge) to put in. THAT also leaked! One more phone call later, they sent me another replacement cartridge that looked completely different than the previous three. I installed it, and Presto!, the drip was gone.

All was well for about 3 months until I started hearing some really loud vibrations in the wall and my water was stuttering and pulsing out of the shower head. The problem does not seem to be present out of the tub faucet however.

I just stumbled across your response about anti-scald technology and how that can be a problem. I was hoping you could elaborate on that for me and maybe tell me how to solve this problem. My hot water is EXTREMELY hot, so this could be my issue.

After all the hassle with the bad parts I FINALLY got my tub wall put back together and finished about month before this started happening. I would hate to have to rip it all back out again!

Any insight would be greatly appreciated!

.....sorry to hijack the post a bit. If anyone can steer to a better place to post this let me know. I'm new to the forum.

Thanks in advance,
Nick

 

[Jadnashua]

A pressure balance spool valve preceeds the volume/mixture part (usually the cartridge). It is designed to help maintain the mixture if the pressure changes on one supply (like if someone flushes a toilet). The valve slides, closing off a little flow of the higher pressure side so the balance (or mix) of the supplies remains close to the same - preventing a radical change in temperature. WHen the pressure returns to 'normal', it slides back to the middle, an keeps both ports open fully. SO, it should only move with pressure changes, and is relatively unaffected by volume changes.

This spool must be free to slide back and forth.

As to preventing the control from getting too hot, they are also required to have some means to adjust the maximum travel of the temperature adjusting handle. On some, it is a screw, on others it is a lever, on others it is a clip or bracket. This should be described in the installation instructions. You usually have to take the trim off to adjust it.

Most cartridges don't have washers, but a loose one can make a really loud vibration as it moves in the water stream.

Hopefully, one of the pros will have more specific help...I've exhausted my 'general' knowledge.

 

[jonesn84]

Thanks for the input Jim.

I have found the hot water limiter on the stem. It is set for full open and I plan on leaving it there.....I like really hot showers...

I think my old cartridge had the spool in it, but my 4th replacement doesn't appear too - unless it is buried somewhere deep within. The new unit is all encased in a plastic housing, so it is difficult to get in and mess with anything. Probably a wise move from the company so guys like me don't attempt to "fix" things and make them worse.

I spoke to a rep. at Price Pfister yesterday and my 5th cartridge is now in the mail. I didn't call looking for a free piece, but when I explained my issues the customer service rep. said the easiest thing to do is replace the entire unit. Here we go again!!!!

Thanks for the input.

-Nick