unexplained hammering

[plumbidiot]

I am wondering if any of the plumbing experts here can help me with my problem. I purchased a home here in southern denver about four years ago. The home is about 14 years old now. A couple years ago we began having issues with hammering sounds when we had to turned on two faucets at once. It is very loud. The hammering occurs where the water tap enters the house in the basement and passes through a whole house filter. I will add a picture.

I started by replacing the filter to see if that would help. I then removed the filter entirely to see if that would make a difference. Then I replaced the plumbing strap that had come loose.

I am tempted next to just remove the entire loop with four elbows in it that holds the water filter. But if the multiple elbows was the cause for the hammering then why did it only show up a couple years ago? Is there some sort of common problem with the water filter systems clogging up?

I would love to get this figured out so that we can turn up the water pressure enough to draw a bath.

Thanks in advance for your help. I am stumped.

 

[plumbidiot]

I should clarify that the hammering noise is constant when the water is at high flow rather then just knocking when the water valve is turned off. Also, the whole house system has been full drained.

 

[desertwater]

I would remove internals on the pressure reducing valve and see if that helps. If it does then you know you need a new prv.

 

[jetswet]

What's the bucket for on the ball valve may I ask?....leak?

 

[plumbidiot]

Desertwater: Thanks for the tip. I will see if I can do that.

Jetswet: The bucket is hung on the shut off for the sprinkler branch off. It came with the house, but I still use it for the drain back each fall after I blow out the sprinklers.

 

[plumbidiot]

I would remove internals on the pressure reducing valve and see if that helps. If it does then you know you need a new prv.

Desertwater: I should note that the prv valve seems to be operating correctly. I was able to reduce the pressure enough to get rid of the hammering... but this leaves me without enough pressure to get even a drip on the second floor if a faucet downstairs is on even just a low flow.

I tried taking apart the valve. I took off the four screws and then the spring. Then I unbolted and popped out the rubber diafram. But this all seemed to be the control side. Do I need to remove the innards from the other side? There is a large hex plug opposite the adjustment screw. See new picture.

Thanks!!

 

[desertwater]

I would remove just the spring. Thats what puts tension on everything.

 

[desertwater]

Is it a specific faucet that produces this hammer? Or is it any faucet in the home. I was gonna say maybe the check valve? But swing checks installed on the vertical are pretty bullet proof.

 

[plumbidiot]

Is it a specific faucet that produces this hammer? Or is it any faucet in the home. I was gonna say maybe the check valve? But swing checks installed on the vertical are pretty bullet proof.

I still need to get back down there and pull the spring...

But regarding a particular faucet. I think the answer is no. It typically occurs when there are any two faucets on at once. Most often that means one of the two is a shower or bath running in our master bath. We almost never use the upstairs bath/shower. The second can be anything... even the washing machine turning on. OR it happens when just the master bath is being drawn at full flow. It's one of those big tubs and the faucet has a really high flow rate. So I just chalked it up to a flow rate factor.

On another note: I changed the water filter yesterday and to my surprise... it did reduce the hammering but not eliminate it. I took a video so you could hear it, but I am unable to upload it. But along with the rattling and clanking and seeing the pipes shake back and forth I can hear a rhythmic water jet noise (thft.. thft...) that matches time to the hammering.

Were would I find the Check Valve?

 

[IFIXH20]

Plumb, Is there another shutoff valve below the PRV. (down towards the floor that is not pictured -- a gate valve maybe)

 

[desertwater]

I'm starting to doubt a prv problem however I have had a similar case to yours where the prv was working and I ended up changing it anyway and the problem went away.

I thought I saw a check valve on the main before the tee for the irrigation. maybe a different picture you had up? I wouldn't worry about it.

do you know what your water pressure is?

Are you on a well?

Sorry for all the questions.

 

[plumbidiot]

Plumb, Is there another shutoff valve below the PRV. (down towards the floor that is not pictured -- a gate valve maybe)

Yes there is. As Desertwater suggest I did have a different picture up on the first post... But it was so large I took it off for readability. But Yes. I thought it may just be some sort of a supply line clean out (ha ha that's why I am a plumbidiot).

PVR: - I took the spring out and it actually just limited the water pressure down all the way.

Water Preassure: It is unknown. The guy working the plumbing section at home depot suggested I check that... Before buying a gauge I went home, found the pvr and adjusted the pressure down until the knocking went away. However, that isn't enough to run two faucets at once, so I dismissed too much pressure as the problem. I have just enough to run two fixtures at once.

Well no, we are not on a well (sorry for the pun). We are on city water from Western Water Works, and I am pretty sure they are culturing some black mold in the city supply lines. But that is another issue.

____________

No problem with the questions. I appreciate all your help.

Since I replaced the strap (you can see the plumbers tape in the upper left corner of the first picture) AND replaced the filter (the two had not been in concert till the last few days) I can now only reproduce the knocking when I turn the master bath faucet on full. Is it normal for a Jacuzzi size tub (mine is the size, but no jets) to have a really high flow faucet on it? I can actually get a few inches of water in the tub in minutes with the drain open. So I have to wonder if a dirty filter started the knocking then making the strap come loose so that once the filter was replaced the knocking continued since the pipes were not supported correctly.

But I am more inclined to think it could still be a problem with the pressure reducing valve or the check valve (ore some other issue) that would be further aggravated by a dirty water filter. Remember that the problem didn't start up until we lived here for a couple years. The situation with the home when we bought it makes me strongly doubt that anyone replaced the filter for a couple years before we bought it too. So I don't think the water filter and strap could explain why we didn't have the problem six months after we moved in.

I am tempted to replace the PRV and CV just to see what happens.

 

[desertwater]

Its been awhile since ive seen that style prv but I believe the big nut on the side maybe a strainer/filter. Im trying to find more info for you.

 

[IFIXH20]

Post a picture of your valve/piping below the prv.

 

[LiQuId]

prv, or any globe valve that may have a loose washer... look for a globe or gate valve in the system .

 

[LiQuId]

Yes there is. As Desertwater suggest I did have a different picture up on the first post... But it was so large I took it off for readability. But Yes. I thought it may just be some sort of a supply line clean out (ha ha that's why I am a plumbidiot).

PVR: - I took the spring out and it actually just limited the water pressure down all the way.

Water Preassure: It is unknown. The guy working the plumbing section at home depot suggested I check that... Before buying a gauge I went home, found the pvr and adjusted the pressure down until the knocking went away. However, that isn't enough to run two faucets at once, so I dismissed too much pressure as the problem. I have just enough to run two fixtures at once.

Well no, we are not on a well (sorry for the pun). We are on city water from Western Water Works, and I am pretty sure they are culturing some black mold in the city supply lines. But that is another issue.

____________

No problem with the questions. I appreciate all your help.

Since I replaced the strap (you can see the plumbers tape in the upper left corner of the first picture) AND replaced the filter (the two had not been in concert till the last few days) I can now only reproduce the knocking when I turn the master bath faucet on full. Is it normal for a Jacuzzi size tub (mine is the size, but no jets) to have a really high flow faucet on it? I can actually get a few inches of water in the tub in minutes with the drain open. So I have to wonder if a dirty filter started the knocking then making the strap come loose so that once the filter was replaced the knocking continued since the pipes were not supported correctly.

But I am more inclined to think it could still be a problem with the pressure reducing valve or the check valve (ore some other issue) that would be further aggravated by a dirty water filter. Remember that the problem didn't start up until we lived here for a couple years. The situation with the home when we bought it makes me strongly doubt that anyone replaced the filter for a couple years before we bought it too. So I don't think the water filter and strap could explain why we didn't have the problem six months after we moved in.

I am tempted to replace the PRV and CV just to see what happens.

there are guages you can buy that screw onto a hose bib to check the pressure, then you can adjust the prv and determine if its functioning withous disasembly.

this shows up over time as the internal washers loosen, then once you turn a fixture on the washer will rumble back and fourth on its stem bolt.

look for a globe or gate valve, or possiblly a swing check ( hwt maybe ? recirc line >?) and try isolating them it often turns out to be the prv though.

 

[plumbidiot]

I replaced the PRV and that was the problem. Thank you all a TON!

 

[phishfood]

Thanks for following up!