# Water hammer?



## whiskywill (20 Mar 2012)

Help!..
I have lived in my current house for the past twenty two years and something has changed. Everytime I flush a toilet (I have 3) the water pipework makes a loud groaning/farting noise. If I then open a tap, anywhere in the house, whilst the cistern is filling, there is a buzz in the pipework. The time the cistern takes to refill seems to be longer than it used to, which suggests that the supply pressure has dropped. Could this cause the noises? I thought water hammer was caused by excessive pressure.


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## Chems (20 Mar 2012)

We had this in our house, it turned out to be that a run of piping in the loft had popped out of its clips and it was resonating and making all this noise when water was flowing. 

Water hammer is when you close the outlet of a high pressure supply and the pressure reflects back off the closed valve back down the pipe/hose causing damage.


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## SketchUp Guru (20 Mar 2012)

It sounds to me as if you have air in the pipes and need to add an air vent. HEre in the US it is normal to install air vents through the roof to allow waste gases somewhere to go. These also helps to prevent the hammering. There are also smaller vents available to allow air to escape the system. these are typically mounted under a sink or some place else out of the way. If there's air trapped in your plumbing, that could cause your cistern to fill slowly.

Maybe you have a vent or two and they are plugged?


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## sparkymarky (20 Mar 2012)

probably un-clipped pipes as chems said, water authorities can raise the mains supply pressure and any given area without notice so it may be that you have had a slight increase in pressure lately.
another possibility which i have had before is quarter turn taps on the mains supply where the ceramic disc is bouncing off the plate which it seals against causing a loud banging, do any other taps drip when the water hammer is making the noise?


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## theturner (20 Mar 2012)

I have had the same problem in the past. It turned out
to be just a new washer needed on the offending tap.
Roger.


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## whiskywill (20 Mar 2012)

theturner":4zj3cm0g said:


> I have had the same problem in the past. It turned out
> to be just a new washer needed on the offending tap.
> Roger.



It's not the tap that is a problem. The noise starts immediately when the toilet is flushed.


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## whiskywill (20 Mar 2012)

Dave R":hiuozlyh said:


> It sounds to me as if you have air in the pipes and need to add an air vent.



If this were the case I would expect to have the same problem with the taps. It only happens when a toilet is flushed. The cistern is filled off the incoming mains supply so there shouldn't be any air trapped.

I definitely don't have any vents to block as I built the house myself and did all of the plumbing, which was fine for 21 1/2 years

Thanks for your suggestion.


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## whiskywill (20 Mar 2012)

sparkymarky":3mqqkx9m said:


> do any other taps drip when the water hammer is making the noise?



No. The noise stops very quickly after the flush and well before the cistern is full. Opening any tap in the house whilst it is filling causes a buzzing somewhere in the pipework. With a bit of care, I can even play a tune on it. It really annoys my wife.


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## theturner (20 Mar 2012)

whiskywill":2wmcvjmu said:


> theturner":2wmcvjmu said:
> 
> 
> > I have had the same problem in the past. It turned out
> ...


The cistern is a tap.Change the washer and I bet a pint of water the problem is solved.


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## Digit (20 Mar 2012)

> It really annoys my wife.



Try a different tune! The things I do to help people! 8) 

Roy.


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## Eric The Viking (20 Mar 2012)

+1 for the cistern's washer (or something similar in its valve).

Failing that, air in the pipework somewhere. have you had reason to drain it down recently, or had some work done on the pipework?

E.


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## misterfish (21 Mar 2012)

We had this years ago in a toilet cistern. I changed the washer but this had little effect. Eventually I fitted a new valve that was described as 'quiet' and also 'eliminates water hammer'. It was and it did.

Misterfish


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## steadyeddie (21 Mar 2012)

Years ago, our cistern made a bit of a racket after flushing. The noise disappeared if the cold tap was turned on. Changing the washer in the cistern cured it completely.

Dave


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## whiskywill (21 Mar 2012)

Thanks for the many and varied suggestions. I'll try 3 new cistern washers. If that doesn't work, anybody want to buy a house?


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## tomatwark (21 Mar 2012)

My parents had this problem when they flushed their bathroom toilet.

We thought it was a water pressure problem adjusted the pressure with the stop tap and it cured it.

For a time, when I visited next, it started to do it again as the main bathroom is only used when they have guests.

I took off the cistern lid and found that there was a little plastic nut with a mesh inside it that was lying in the bottom of the cistern, that should have been screwed onto the end of the valve, it had worked lose over time and fallen off.

Put it back on problem cured instantly.

Tom


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## whiskywill (27 Apr 2012)

At last! Yesterday evening I changed the diaphragm/washer in the ball valve in the noisiest cistern and it worked. Silent flushing. I have now got to do the other two and I can use the toilet at night. No more bed wetting.


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## hanser (29 Apr 2012)

whiskywill":10ep68oh said:


> At last! Yesterday evening I changed the diaphragm/washer in the ball valve in the noisiest cistern and it worked. Silent flushing. I have now got to do the other two and I can use the toilet at night. No more bed wetting.



I bet that's a relief :lol:


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## Lons (29 Apr 2012)

whiskywill":18n4bljn said:


> Thanks for the many and varied suggestions. I'll try 3 new cistern washers. If that doesn't work, anybody want to buy a house?



It almost certainly is not all 3 cisterns. If it happens whichever WC is flushed then the real problem is within the pipework system and it becomes a process of elimination. try adjusting the main stopcock then try to track down the source of the noise (might mean a crawl in the loft  ). Sometimes with plastic pipe especially, if it comes loose from the clips (not always fitted anyway :roll: , it can belly up causing an air pocket.

If it's the result of 1 WC , ( does your comment about being slower to fill mean all or 1 cistern?,) then the likely cause is the inlet valve. If the older type, metal or plastic with arm / ball float then washer is easily changed. Check also that the float isn't holes and waterlogged. If the newer type, it's better IMO to change the whole valve. personally, I wouldn't use a cheaop version - just aren't worth the effort.

I change around 10 - 15 a year, nearly all newer versions - the oldies were much longer lived.

Bob


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## whiskywill (1 May 2012)

Lons":hz307hpz said:


> It almost certainly is not all 3 cisterns. If it happens whichever WC is flushed then the real problem is within the pipework system and it becomes a process of elimination. try adjusting the main stopcock then try to track down the source of the noise (might mean a crawl in the loft  ). Sometimes with plastic pipe especially, if it comes loose from the clips (not always fitted anyway :roll: , it can belly up causing an air pocket.
> 
> If it's the result of 1 WC , ( does your comment about being slower to fill mean all or 1 cistern?,) then the likely cause is the inlet valve. If the older type, metal or plastic with arm / ball float then washer is easily changed. Check also that the float isn't holes and waterlogged. If the newer type, it's better IMO to change the whole valve. personally, I wouldn't use a cheaop version - just aren't worth the effort.
> 
> ...



Changing the first 26p diaphragm lessened the noise made by the second cistern. Changing the second diaphragm lessened the noise made by the third cistern. Changing the third diaphragm stopped all noise completely. I feel that there has been a general slowing of the filling rate which I can't change because the stop tap is fully open. There are no pipes in the loft. It is a self build house and all pipes are copper. They run in between and through the first floor joists and only reappear very close to their end points so no chance of checking for loose pipes unless I rip up carpets and floorboards.

However, all is now peaceful and, once again, thanks for all suggestions.


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## Lons (1 May 2012)

whiskywill":2bnvcpv0 said:


> Changing the first 26p diaphragm lessened the noise made by the second cistern. Changing the second diaphragm lessened the noise made by the third cistern. Changing the third diaphragm stopped all noise completely. I feel that there has been a general slowing of the filling rate which I can't change because the stop tap is fully open. There are no pipes in the loft. It is a self build house and all pipes are copper. They run in between and through the first floor joists and only reappear very close to their end points so no chance of checking for loose pipes unless I rip up carpets and floorboards.
> 
> However, all is now peaceful and, once again, thanks for all suggestions.



 Sorry about that, I somehow missed a couple of previous posts so didn't know you had sorted it. The odds against all 3 cisterns would be huge unless it has developed over a period of time or you've had a bad batch. Cheap fix though  

I managed to sort out a water hammer problem yesterday co-incidentally though not the same cause. The guy had fitted a 3 bar shower pump as part of a diy bathroom refurbishment and each time it shut off it set off a hammer in a stud wall. The wife was threatening divorce and didn't relish plasterboard removal so as I have a flexi inspection camera I drilled a small hole near each joist and found that the builder had pushed 15mm copper pipes through the noggins and they weren't clipped. It hadn't happened previously so the pump was the cause but as I hadn't supplied it and they didn't want to spend more, the solution was to squirt expanding foam through the holes and let it set. Sorted and hopefully the foam shouldn't cause future problems though I did put in a disclaimer :wink: 

Bob


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