Water Hammer Arrestor
 

After listening to water hammer on the pipes for the last 30 years I've
finally got round to doing something about it (best not to rush these
things) and fitted an arrestor -
http://www.toolstation.com/shop/Plum...SP/d/sd/p93058

I've had most of the plumbing in the house exposed at some time or other
but have never been able to find the source of the problem. Only a
couple of 3M or 4M stretches have never been able to be checked so I
fitted it in a section as close to what I presumed to be the source of
the hammer as possible.

It's not worked. Nothing has changed.

Do the arrestors work (if they're going to) as soon as they are fitted?

The top of it has what looks like a bicycle pump connector. Do I need to
get some pressure into it?

TIA

--
F

Water Hammer Arrestor
 

In article ,
F news@nowhere writes:
After listening to water hammer on the pipes for the last 30 years I've
finally got round to doing something about it (best not to rush these
things) and fitted an arrestor -
http://www.toolstation.com/shop/Plum...SP/d/sd/p93058

I've had most of the plumbing in the house exposed at some time or other
but have never been able to find the source of the problem. Only a
couple of 3M or 4M stretches have never been able to be checked so I
fitted it in a section as close to what I presumed to be the source of
the hammer as possible.

It's not worked. Nothing has changed.

Do the arrestors work (if they're going to) as soon as they are fitted?

The top of it has what looks like a bicycle pump connector. Do I need to
get some pressure into it?

I don't know if they come pressurised (my boiler expansion vessel did).
If you pressurise it to half your water pressure, the diaphragm
will be end up midway when you connect up to the supply, so it will
take both +ve and -ve pressure shocks.

--
Andrew Gabriel
[email address is not usable -- followup in the newsgroup]

Water Hammer Arrestor
 

In article , F
news@nowhere.? writes
After listening to water hammer on the pipes for the last 30 years I've
finally got round to doing something about it (best not to rush these
things) and fitted an arrestor -
http://www.toolstation.com/shop/Plum...+Arrestor+12+M
BSP/d/sd/p93058

I've had most of the plumbing in the house exposed at some time or other
but have never been able to find the source of the problem. Only a
couple of 3M or 4M stretches have never been able to be checked so I
fitted it in a section as close to what I presumed to be the source of
the hammer as possible.

It's not worked. Nothing has changed.

Do the arrestors work (if they're going to) as soon as they are fitted?

The top of it has what looks like a bicycle pump connector. Do I need to
get some pressure into it?

TIA

I agree it's best not to rush these things.

I assume by water hammer you mean banging in the pipes when a tap is
turned off sharply?

It's handy to understand that this kind of water hammer is about shock
waves travelling along a pipe when a flow is interrupted and making a
bang when the shock hits a restriction in the pipework, whether that be
the incoming stop-cock, a narrowing in pipework or if really unlucky, a
side limb of a T joint.

That said, it's common for water hammer to be solved by simply fixing
down the pipes in a system securely so that they can't jump about when a
pressure wave is passing through them. That is certainly the case when
it is a vibration in pipes when the pipes are on rather than a bang when
they are turned off. Try this first.

The device you linked to is a typical one and they are ready to use out
of the box so no need to pump them up, and as they have such a low
volume you could easily empty them by just trying to measure the
pressure so best left alone.

They can be a bit hit or miss but they are generally best placed to
catch the shock wave at the opposite end of the pipework from the source
as that is where the sharpest shock is. If you've placed it at the end
of a branch then I'm afraid it's probably the wrong place. I would first
place one of these as close as possible to the incoming stop-cock.

See also: http://wiki.diyfaq.org.uk/index.php?title=Noisy_Pipes
--
fred
BBC3, ITV2/3/4, channels going to the DOGs

Water Hammer Arrestor
 

F wrote:
After listening to water hammer on the pipes for the last 30 years I've
finally got round to doing something about it (best not to rush these
things) and fitted an arrestor -
http://www.toolstation.com/shop/Plum...SP/d/sd/p93058


I've had most of the plumbing in the house exposed at some time or other
but have never been able to find the source of the problem. Only a
couple of 3M or 4M stretches have never been able to be checked so I
fitted it in a section as close to what I presumed to be the source of
the hammer as possible.

It's not worked. Nothing has changed.

I fitted one of these recently to cure a problem with a noisy toilet
cistern; I fitted it at a convenient location in the cold water pipework
(several meters away from the loo) but it did absolutely nothing; I then
demounted it and repositioned it immediately below the cistern where
it's unsightly but reasonably effective. Certainly not perfect though.

David

Water Hammer Arrestor
 

On 9 Oct, 16:38, fred wrote:
In article , F
news@nowhere.? writes

After listening to water hammer on the pipes for the last 30 years I've
finally got round to doing something about it (best not to rush these
things) and fitted an arrestor -
http://www.toolstation.com/shop/Plum...+Shock+Arresto...
BSP/d/sd/p93058

I've had most of the plumbing in the house exposed at some time or other
but have never been able to find the source of the problem. Only a
couple of 3M or 4M stretches have never been able to be checked so I
fitted it in a section as close to what I presumed to be the source of
the hammer as possible.

It's not worked. Nothing has changed.

Do the arrestors work (if they're going to) as soon as they are fitted?

The top of it has what looks like a bicycle pump connector. Do I need to
get some pressure into it?

TIA

I agree it's best not to rush these things.

I assume by water hammer you mean banging in the pipes when a tap is
turned off sharply?

It's handy to understand that this kind of water hammer is about shock
waves travelling along a pipe when a flow is interrupted and making a
bang when the shock hits a restriction in the pipework, whether that be
the incoming stop-cock, a narrowing in pipework or if really unlucky, a
side limb of a T joint.

That said, it's common for water hammer to be solved by simply fixing
down the pipes in a system securely so that they can't jump about when a
pressure wave is passing through them. That is certainly the case when
it is a vibration in pipes when the pipes are on rather than a bang when
they are turned off. Try this first.

The device you linked to is a typical one and they are ready to use out
of the box so no need to pump them up, and as they have such a low
volume you could easily empty them by just trying to measure the
pressure so best left alone.

They can be a bit hit or miss but they are generally best placed to
catch the shock wave at the opposite end of the pipework from the source
as that is where the sharpest shock is. If you've placed it at the end
of a branch then I'm afraid it's probably the wrong place. I would first
place one of these as close as possible to the incoming stop-cock.

See also:http://wiki.diyfaq.org.uk/index.php?title=Noisy_Pipes
--
fred
BBC3, ITV2/3/4, channels going to the DOGs

...

Water Hammer Arrestor
 

On 09/10/2009 19:16 Lobster wrote:

F wrote:

It's not worked. Nothing has changed.

I was wrong. It's not worked but something has changed: it's louder!

I fitted one of these recently to cure a problem with a noisy toilet
cistern; I fitted it at a convenient location in the cold water pipework
(several meters away from the loo) but it did absolutely nothing; I then
demounted it and repositioned it immediately below the cistern where
it's unsightly but reasonably effective. Certainly not perfect though.

As it's louder, I seem to have got the correct section of pipe.

I'll certainly be taking it out but there's no-where else on that
section to put it as the rest of it is either boxed in or under a tiled
floor where I fixed the pipes to joists before tiling.

--
F

Water Hammer Arrestor
 

In article ,
F news@nowhere writes:
On 09/10/2009 19:16 Lobster wrote:

F wrote:

It's not worked. Nothing has changed.

I was wrong. It's not worked but something has changed: it's louder!

I fitted one of these recently to cure a problem with a noisy toilet
cistern; I fitted it at a convenient location in the cold water pipework
(several meters away from the loo) but it did absolutely nothing; I then
demounted it and repositioned it immediately below the cistern where
it's unsightly but reasonably effective. Certainly not perfect though.

As it's louder, I seem to have got the correct section of pipe.

I'll certainly be taking it out but there's no-where else on that
section to put it as the rest of it is either boxed in or under a tiled
floor where I fixed the pipes to joists before tiling.

One possible cause of water hammer is a deadleg with air trapped in it.
Now, a Water Hammer Arrestor is simulating a deadleg with air trapped in it,
so you might want to see if you have some more real ones on the pipework.

--
Andrew Gabriel
[email address is not usable -- followup in the newsgroup]

Water Hammer Arrestor
 

"Andrew Gabriel" wrote in message
...
In article ,
F news@nowhere writes:
On 09/10/2009 19:16 Lobster wrote:

F wrote:

It's not worked. Nothing has changed.

I was wrong. It's not worked but something has changed: it's louder!

I fitted one of these recently to cure a problem with a noisy toilet
cistern; I fitted it at a convenient location in the cold water pipework
(several meters away from the loo) but it did absolutely nothing; I then
demounted it and repositioned it immediately below the cistern where
it's unsightly but reasonably effective. Certainly not perfect though.

As it's louder, I seem to have got the correct section of pipe.

I'll certainly be taking it out but there's no-where else on that
section to put it as the rest of it is either boxed in or under a tiled
floor where I fixed the pipes to joists before tiling.

One possible cause of water hammer is a deadleg with air trapped in it.
Now, a Water Hammer Arrestor is simulating a deadleg with air trapped in
it,
so you might want to see if you have some more real ones on the pipework.

--
Andrew Gabriel
[email address is not usable -- followup in the newsgroup]

I believe that cheap washing machine hoses can lead to water hammer as they
are slightly elastic.

Water Hammer Arrestor
 

On 10/10/2009 18:06 Chris Hogg wrote:

Something else I've seen suggested is a flat baffle plate fixed
horizontally under the float on the ball valve in the cold water tank.
This helps stop the float from 'bouncing' and hence perpetuating the
knocking when a tap is turned off suddenly.

Thanks for the suggestion but, some time ago, I went up into the loft
and held the floats up to stop either of the valves from opening.
Management operated the cold water tap and the hammer was still there.

--
F

Water Hammer Arrestor
 

On 10/10/2009 13:37 Andrew Gabriel wrote:

One possible cause of water hammer is a deadleg with air trapped in it.
Now, a Water Hammer Arrestor is simulating a deadleg with air trapped in it,
so you might want to see if you have some more real ones on the pipework.

I'm pretty sure there's a horizontal dead-leg (remnant of a water supply
into the garage) and I have long suspected it's the problem but I can't
get into that space to check.

Seems odd that introducing a simulated dead-leg is supposed to cure the
problem...

--
F

Water Hammer Arrestor
 

"F" news@nowhere wrote in message
.. .
On 10/10/2009 18:06 Chris Hogg wrote:

Something else I've seen suggested is a flat baffle plate fixed
horizontally under the float on the ball valve in the cold water tank.
This helps stop the float from 'bouncing' and hence perpetuating the
knocking when a tap is turned off suddenly.

Thanks for the suggestion but, some time ago, I went up into the loft and
held the floats up to stop either of the valves from opening. Management
operated the cold water tap and the hammer was still there.

--
F


Managed to stop this with a home made version of the hammer arrestor (22mm
pipe with cycle valve at the top) but it needed regular top ups of air with
a cycle pump. Finally stopped for good when I replaced the toilet and used
a flexible coupler. A 500mm one arranged in a loop seemed quite effective
as a cheap hammer arrestor.

Chris K

Water Hammer Arrestor
 

F wrote:
On 10/10/2009 13:37 Andrew Gabriel wrote:

One possible cause of water hammer is a deadleg with air trapped in it.
Now, a Water Hammer Arrestor is simulating a deadleg with air trapped
in it,
so you might want to see if you have some more real ones on the pipework.

I'm pretty sure there's a horizontal dead-leg (remnant of a water supply
into the garage) and I have long suspected it's the problem but I can't
get into that space to check.

Seems odd that introducing a simulated dead-leg is supposed to cure the
problem...


Changes the resonant frequency of the system.

Andy

Water Hammer Arrestor
 

On 10/10/2009 21:44 Chris K wrote:

Finally stopped for good when I replaced the toilet and used
a flexible coupler. A 500mm one arranged in a loop seemed quite effective
as a cheap hammer arrestor.

I've got five of these on the cold pipes in one place or another but the
hammer hasn't changed since I installed them.

There's a few of us on the street who would like to meet the 'plumber'
who was employed when they built the houses. Pipes not fixed and left to
hang are quite common: a neighbour had one that was left resting on a
nail until years of movement wore a hole through it. I've tried to
rectify things as I've worked my way through extending and refurbishing
(now refurbishing the refurbishments!) the house over the past 30 years
but there are a couple of areas that just are not easily accessible.

--
F