HELP - toilet flush makes noises like jackhammer

Discussion in 'Plumbing Forum' started by jennebelle, Aug 23, 2009.

  1. Aug 23, 2009 #1

    jennebelle

    jennebelle

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    As mentioned in title, when I flush my toilet some evenings (generally this issue happens most between 11pm and 2am) it can make the most disturbing noise. Something in the pipes seems to take over the building with a pressure noise that sounds like a jackhammer. If I rush to the toilet, take off the lid, and pull up the ballcock then the noise will stop temporarily. But if I drop the ball before the water has filled completely then the noise begins again. Attempts at problem solving include trying to loosen and tighten the screw at the top of the toilet fill valve but that has not fixed the problem, rather it seems to increase the fill time and create gurgly noises towards the end of the fill cycle.

    Any helpful suggestions would be much appreciated!
     
  2. Aug 23, 2009 #2

    Nestor_Kelebay

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    There are two likely candidates that could be responsible for creating this noise; a loose washer in a water valve supplying water to the toilet, or a problem with the closing of the rubber diaphragm inside the ballcock (probably just a rotting rubber diaphragm).

    The most likely cause would be a loose rubber washer in the water shut off valve to the toilet. That's cuz if the washer is loose, and capable of moving back and forth on the screw that's supposed to hold it in place, then you can rapid opening and closing of that valve. What happens is water gets behind the rubber washer. That water is the same pressure as the water in the supply piping. However, because the washer is larger in diameter than the seat it presses against, and FORCE is equal to pressure times area, there is a net force pushing the washer down against the seat. If, when that washer moves, the water behind the washer can leak out faster than it can leak in, the movement of the washer will cause it to move back off the seat again, allowing water to flow through the valve again. And, if water starts to then get behind the washer again to cause it to move forward again, you can have the water flow into the tank start and stop and start and stop again repeatedly, which could make the pipes rattle like crazy and cause the jack hammering noise you're hearing.

    Toilet ballcocks (or fill valves) shut off the water flow using exactly the same principle as the water mixing valve on a washing machine. In both cases the method is nearly identical to the loose washer described above. You have a rubber diaphragm that fits over an opening through which water enters the toilet tank. Both sides of that rubber diaphragm are exposed to the city water pressure, but the area exposed to that pressure is larger on one side of the diaphragm than the other. So, the difference in area again causes a net force causing the rubber diaphragm to press against that opening and stop water flow into the toilet tank.

    When you flush the toilet, the dropping of the float causes a small plug to release the pressure on the large area side of the diaphragm, and that causes the water supply pressure on the low area side to pop the diaphragm open, allowing water to rush into the toilet tank. Once the tank is empty, the flush valve closes again, and the water starts filling the tank again until it raises the float. The raising of the float causes the plug to plug up that hole on the large area side again, and as the pressure quickly equalizes across the diaphragm, it presses against that hole to stop further water flow into the tank.

    Now, what happens if the hole that gets plugged on the large area side of the diaphragm is worn out and on the verge of leaking? If there's leakage past that plug, then you can have the pressure build up and leak out and build up and leak out behind the diaphragm repeately causing the ballcock to open and close and open and close and open and close again in rapid succession, causing the pipes to rattle and making a noise from a high pitched squeel to the sound of an ocean liner's fog horn and everything in between.

    I'd replace the rubber diaphragm in the ballcock and also shut off the water upstream of the shut-off valve to the toilet and check the washer in that shut-off valve.
     
  3. Aug 23, 2009 #3

    Redwood

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    Most likely the angle stop valve supplying the toilet as Nestor said.

    Sometimes it can be another valve in the line have you touched any of them lately?

    Make sure the toilet stop valve is all the way open sometimes they stop making the noise then...
     
  4. Aug 23, 2009 #4

    CraigFL

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    I've also seen the anti-waterhammer supressors(accumulators) they put on the water lines behind the wall get waterlogged. Sometimes draining the pipes and repressuring them will help.
     
  5. Aug 23, 2009 #5

    jennebelle

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    Thank you for the suggestions. The fill valve is very loose (you can hear the water dripping in with the slightest touch). Will that be corrected if i find the loose washer or could it possibly be more serious?
     
  6. Aug 24, 2009 #6

    Nestor_Kelebay

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    Can you elaborate on that?

    You say the fill valve is very loose. Does that mean that it wobbles when you touch it? Does any water spill from the tank onto the floor when you move the fill valve?

    You say you can hear the water dripping "in" with the slightest touch.
    Where do you hear water "dripping"?
    Do you mean "flowing" into the tank, rather than dripping?
    What are you touching and where to hear the water coming in?
     
  7. Aug 24, 2009 #7

    inspectorD

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    Remove jackhammer.....:agree: with the others.
     
  8. Aug 25, 2009 #8

    jennebelle

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    Yes, the fill valve wobbles when I touch it. No water has spilled onto the floor. I don't understand the drip noise, but I believe it is coming from the tube/valve rather than flowing from the fill entry hole...

    By touching the valve, i am referencing when i was messing with the tightness of the screw at the top of the tube and when we do the emergency stop of the noise by pulling up and leveling the ball...

    What should be the first step in finding the problem to be fixed?

    Sorry if I've used the wrong terms. And thanks for your continued help.
     
  9. Aug 26, 2009 #9

    Nestor_Kelebay

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    You should be able to tighten that wobbly fill valve by turning the brass or plastic nut on the bottom of it (under the toilet tank).

    Typically, those fill valves that have a float and horizontal float arm will have the rubber diaphragm I described at the TOP of the fill valve, so that suggests to me that the noise is being caused by the rubber diaphragm in the fill valve rather than a loose washer in the water shut off valve. If you take the top off the fill valve, the rubber diaphragm will be right under that top piece.

    Don't take the top off your fill valve without first closing the water shut off valve to the toilet. You'll notice water starting to spray out the top of the fill valve if you don't, and that's fair warning not to proceed further if you don't want to have water spraying all over the place.
     
    Last edited: Aug 26, 2009
  10. Aug 26, 2009 #10

    JALEXED2

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    You may have a couple problems going on.

    If your ballcock is leaking, it will eventually fill up the tank and will raise the water level to the height of the overflow tube and pass water into the bowl.

    If the flapper valve (lower "flap" at the bottom of the tank) is leaking, you will also have water flowing into the bowl. Place some food dye in the tank and see if the color of the water in the bowl changes to the color of the food dye. If so, you have a leaking flapper valve. This could be the dripping noise you hear. A new flapper valve is about $3.

    If the ballcock is leaking as you somewhat suggest, replace it - don't putz around trying to fix it. A new ballcock is under $10 at your local hardware store. They are pretty easy to replace. Any hardware clerk would be glad to help instruct you. It sounds like you have some issues going on with the ballcock anyway.

    If your problems persist and the noise continues, the problem will be within the water lines - which sounds more like "water hammer". That is when air gets trapped in the lines and "hammers" when the valves are turned on/off. It does seem weird that your problem is between 11pm and 2am. Perhaps your water pressure is higher at this time of night and the water hammer is more noticeable??? Verify that the water hammer does not occur during the day just to clearly understand if there is any "time of day" issue here.

    If water hammer is the problem, CraigFL suggests draining your system which I agree with. If you need assistance with draining your system, write back and the DIY gang can give you instructions.
     
  11. Aug 26, 2009 #11

    Nestor_Kelebay

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    Jalexed2:

    I believe that you made a mistake in your post when you said:

    You seem to be saying that it's the trapped air that's causing the problem, and that's not correct.

    The newbies are gonna wonder, for example, exactly how the air trapped in the water pipes causes noise to be made, and why they don't hear a similar noise whenever air gets into other water pipes, like drain pipes.

    Also, oxygen is continually being produced inside the water heater when you heat cold water. Cold water will hold more O2 in solution than hot water, so often O2 gas will be driven out of the cold water when it's heated. In fact, if you look for it, you very often see tiny "blasts" of compressed gas (air, maybe?) come out of the hot water faucets in your home when you're running hot water. They're very short lived, but they're there. So, why wouldn't EVERY house with a water heater have water hammer problems?

    And, the sharpest newbies are gonna ask: "Why doesn't the air come out when you run the water?" (And they'd be right of course.)

    So, lemme explain water hammer...

    Water hammer is really just the shaking of water supply pipes as a result of abruptly stopping the flow of water through them.

    You see, water is heavy, and when it's flowing through a long pipe, it can have a lot of momentum. One of the laws of physics is "Conservation of Momentum", which basically says that momentum is energy and energy can neither be created nor destroyed. You have to have the same amount of energy after an event as you did before it. A figure skater turning slowly with her arms out and then spinning faster as she brings her arms in is an example of Conservation of Angular Momentum.

    Some people might ask "Where, pray tell, is the law of Conservation of Momentum when a Boeing 747 nose dives into the ground?", and so it's probably better to call it Conservation of Energy rather than Conservation of Momentum.

    So, when you have water running quickly in a pipe, then the momentum of the water wants to keep it going at the same speed. But if a suddenly closed faucet is preventing that, then all the water molecules pile up against an elbow or tee or valve or whatever it is in the pipe that's now stopping them from continuing to flow at the same speed. It's just the same as if you have a crowded bus come to an emergency stop. All the people inside would pile up against the front windshield of the bus, which is what's now stopping them from continuing to move at the same speed as before. The momentum of those people is all born by the windshield, which would pop out of the bus if it could.

    When the water piles up against an elbow or a tee, the momentum of the water is imparted to that elbow or tee, and the pipe moves as a result. When the pipe moves, then it'll spring back to it's original position, and it's the shaking of the pipes as a result (and the resulting bouncing around of the pipes against the walls or joists) that makes the noise we call "water hammer".

    Water hammer can sound like your pipes are shaking themselves loose inside your walls, but it really doesn't do any harm. It just sounds like there's being harm done.

    Installing surge arrestors on pipes that have water hammer helps prevent the problem because they use the water's momentum to compress air rather than move the pipe. That is, much of the energy of the water is used to compress a gas in the surge arrestor, and so less energy is imparted to the pipe. The pipe moves less and there's less bouncing around and so less noise.

    But, really the best solution is to fasten down the pipes more securely so they don't move in the first place. (in that case, the momentum of the water goes into stretching the copper pipe an infinitesmally small amount before it snaps back to it's original length) ((otherwise, you'd be destroying energy if the water's momentum merely "vanished" cuz the pipe didn't move))

    You can prevent water hammer that occurs on the supply lines going to faucets simply by closing the faucet slowly. By reducing the speed of the water gradually, you have less momentum available to move the pipe.

    Water hammer tends to be worst on the supply piping going to dishwashers, clothes washing machines and toilet tank ballcocks (fill valves) because of the way the valves in these things work. These valves close very rapidly, and that doesn't allow for the momentum of the water to be reduced gradually like you can by closing a faucet slowly.

    Draining the water out of the piping will only help if the poster has "home made" surge arrestors on his/her water piping. You can make such a thing by simply providing some extra vertical copper pipe at the tops of vertical risers so that air will naturally be trapped in that additional pipe when the system is filled with water. The problem with these home made surge arrestors is that they are prone to becoming water logged, and therefore ineffective at preventing water hammer. Good quality surge arrestors will have a piston or diaphragm inside them that forms a physical seal between the water and the gas, and that prevents them from becoming water logged.

    So, water hammer is all about physics and energy. Air plays no role in creating water hammer. In fact, air trapped inside the supply piping would actually help reduce water hammer because that air would have less momentum than water, and the momentum of the water upstream of the trapped air would go into compressing that air rather than moving the pipe.

    So, it's the momentum in the pipe, not the air in it, that causes water hammer. :)
     
    Last edited: Aug 27, 2009
  12. Aug 26, 2009 #12

    Redwood

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    So Nestor based on your own description of a water hammer the jack hammering noise cannot be a water hammer because it only occurs while water is flowing.:D

    This startling revelation puts the cause squarely on debris moving in the flow while water is flowing....

    Or that loose washer at the angel stop valve...:D
     
  13. Aug 27, 2009 #13

    Nestor_Kelebay

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    Yeah, but I changed that cuz I realized that a loose washer or a rubber diaphragm in the ballcock could cause the water to flow and stop and flow and stop in rapid succession. And, even though the water is still filling the tank, every time it stops flowing for an instant, you can have water hammer as a result.

    And, yes, it could be a loose washer in the shut off valve, but if the noise goes away when the poster holds the ballcock float arm in a certain way, that suggests it's the diaphragm in the ballcock.

    It wouldn't be hard to change both.
     
    Last edited: Aug 27, 2009
  14. Sep 3, 2009 #14

    jennebelle

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    It is crazy -- the noise only happens late at night -- and it doesn't happen every time -- and it doesn't happen at the start of the fill cycle, it happens when you're on the other side of the room washing hands a good 15-20 seconds after making the flush... Any thoughts?
     
  15. Sep 5, 2009 #15

    jennebelle

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    The nut on the bottom of the toilet tank is very secure. Is there anyway to tighten the fill valve on the interior of the tank or should I plan on purchasing and replacing the fill valve and ballcock? Everything should be new (house built 2006) so I don't understand why this issue keeps occuring...
     
  16. Sep 6, 2009 #16

    Nestor_Kelebay

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    Jennebelle:

    The ballcock is also called the "fill valve". They're one and the same thing.

    The correct name for the other thing that's located more toward the geographic center of the toilet tank is the "flush valve". When you flush the toilet, the flush valve lets the water out, and the ballcock or fill valve fills the toilet tank up again. The fill valve also goes by the alias "ballcock", but so far as I know, there is no other commonly used name for the flush valve.

    Now we are getting somewhere. You're saying that the fill valve (aka: "Ballcock" ) is wobbly on the inside of the toilet, but the nut on the underside of the tank that clamps holds that fill valve in place is tight.

    That's telling me that your ballcock (aka: "Fill Valve") is busted.

    I think you need a new fill valve if you can wobble the part of the fill valve that's inside the tank without being able to budge the large plastic (or brass) nut underneath it.

    Amongst most DIY'ers, the best fill valve on the market, and probably the most popular one for sale in home centers, is the Fluidmaster 400A. People really liked them, so Fluidmaster did the best thing they could do for their shareholders, and jacked up the price on them so you're paying about $15 for one now.

    One advantage of the Fluidmaster 400A that it shared with it's predecessor the Fluidmaster 200A was the ability to replace the working portion of the valve without removing the whole valve from the toilet tank. You just shut the water off to the toilet, slip the locking collar upward to disengage the locking mechanism, and give the upper portion of the valve a good strong jerk, and it'll separate into an upper portion with the float and rubber diaphragm and a lower portion with no moving parts that remains in the toilet tank. That way, in future you can replace all the working parts of the valve simply by yanking the working assembly off the old valve and popping on the working assembly from a new valve.

    It's best to yank the two parts of the Fluidmaster 400A apart just to see how much force you need to apply BEFORE installing it in your toilet. Don't worry, you won't harm anything by doing that. It's a feature of this valve that most people don't know about, but it remains true to the 200A tradition that everyone knew about.

    I expect that replacing the fill valve will go a long way to solving the problem.
     
    Last edited: Sep 6, 2009
  17. Sep 6, 2009 #17

    jennebelle

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    THANK YOU!!! I really appreciate all of your suggestions and continued followup.
     
  18. Sep 9, 2009 #18

    jennebelle

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    so we got and installed the new fill valve -- and now the toilet is leaking below the tank...
     
  19. Sep 10, 2009 #19

    Nestor_Kelebay

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    Tighten the plastic nut holding the fill valve tight, and replace the plastic tube going from the water shut off valve to the fill valve with a braided stainless steel flex supply tube.
     
  20. Sep 10, 2009 #20

    jennebelle

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    should we use plumbers putty to help seal the connection?
     

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