On 2016-09-25, John Rumm wrote:

On 24/09/2016 23:45, Fredxxx wrote:

Most systems I have come across don't have any means to drain the header
tank to help replacing the gate valve. Was it a case of syphoning water
out of the header tank or an otherwise easy job?

I did not bother draining - I have a couple of conical rubber bungs[1]

We poked one into the outlet of the cold cistern, and the other into the
vent pipe from the cylinder over the cistern. That meant we only lost a
few feet of pipe's worth of water.

[1] Like:

https://www.cityplumbing.co.uk/Regin...egr05/p/581501

You can either poke the end in a pipe, or the inside of the bungs are
hollow, with a flange at the top, so they can be forced over the end of
a pipe as well.

Looks too simple to work! ;-)

How do those work for changing radiator valves? It seems to me you're
still going to spray water between unscrewing the old valve & getting
the bung in, & again between removing the bung & screwing the new
valve together.

On 30/09/2016 10:06, Adam Funk wrote:
On 2016-09-25, John Rumm wrote:

On 24/09/2016 23:45, Fredxxx wrote:

Most systems I have come across don't have any means to drain the header
tank to help replacing the gate valve. Was it a case of syphoning water
out of the header tank or an otherwise easy job?

I did not bother draining - I have a couple of conical rubber bungs[1]

We poked one into the outlet of the cold cistern, and the other into the
vent pipe from the cylinder over the cistern. That meant we only lost a
few feet of pipe's worth of water.

[1] Like:

https://www.cityplumbing.co.uk/Regin...egr05/p/581501

You can either poke the end in a pipe, or the inside of the bungs are
hollow, with a flange at the top, so they can be forced over the end of
a pipe as well.

Looks too simple to work! ;-)

How do those work for changing radiator valves? It seems to me you're
still going to spray water between unscrewing the old valve & getting
the bung in, & again between removing the bung & screwing the new
valve together.

They are not primarily intended to be used on the rad tails themselves.
They are used in vented CH systems to block of the Feed & Expansion
connection to/from the CH header tank, and also the CH vent pipe over
the tank. Once that is done, you have created an air lock that makes it
harder for water to escape.

So say you wanted to change a rad valve, you would stick the plugs into
the expansion tank/vent pipe, and then turn off both rad taps. Now drain
just that rad. Uncouple the valve you want to change from the rad, and
now you can remove it from the pipe. You will get a small amount of
spillage - but the whole system will not be able to drain out of the
open pipe, because its sealed and air can not enter elsewhere to let the
water out.




--
Cheers,

John.

/================================================== ===============\
| Internode Ltd - http://www.internode.co.uk |
|-----------------------------------------------------------------|
| John Rumm - john(at)internode(dot)co(dot)uk |
\================================================= ================/

On Tuesday, 27 September 2016 22:28:56 UTC+1, John Rumm wrote:
On 27/09/2016 19:02, harry wrote:
On Tuesday, 27 September 2016 12:11:05 UTC+1, John Rumm wrote:
On 27/09/2016 10:12, Dan S. MacAbre wrote:

What is the 'valve gate party trick' to which the OP refers? I might
need to make use of it one day.

I did expand that in the op... its not a trick one plays on gate valves,
but a trick they play on you!

i.e. When you attempt to turn them off, they will frequently fail to
seal completely (due to the presence of debris / sludge / hard water) in
the gate recess - so you often end up with a trickle of water still
letting by the valve. Then when you attempt to open the valve again, the
spindle may snap internally before it withdraws the gate from its
recess, leaving the gate closed, and the hand wheel turning endlessly,
but not actually doing anything.

You will have to excuse harry, he has delusions of competence
(presumably influenced by using lots of nice large shiny commercial gate
vales in industry, and naff all experience of the crappy things sold for
domestic plumbing).

Drivel.

ok then, just delusions?

Using incorrect valves in any situation is down to ignorance, idleness and/or greed.

Well at least you seem to now accept that gate valves are "incorrect
valves" - so that is progress.

You seem to be one of them.

That does not even make semantic sense.

The crooks installing these cheap brass valves are ripping people off and get away with it because it takes a few years for the damage to be done/become apparent.

Well the one I replaced the other day was not installed recently, and
likely 40+ years old. Typical failure mode though. So I guess the
"crook" that installed it is not too fussed (if even still alive).

DZR gate valves fail in exactly the same way, and for the same reasons
as "normal" ones.

How can they as there is no zinc in them?
Being bronze, the are an alloy of copper and tin.

On 30/09/2016 17:14, harry wrote:
On Tuesday, 27 September 2016 22:28:56 UTC+1, John Rumm wrote:


DZR gate valves fail in exactly the same way, and for the same reasons
as "normal" ones.

How can they as there is no zinc in them?

The failure is not caused by lack of zinc. Its a result of them being
designed by a moron.

Gate valves fail because the gate recess fills with crap: like hard
water scale, magnetite, rust, particulates etc. This makes them harder
to close, and also ensures that the gate will not seat correctly, thus
letting by.

The extra friction / misalignment on the gate also causes it to jam and
get stuck in the recess. The tap mechanism being made from cheese in the
first place is then not man enough to withdraw the gate. The spindle
snaps internally, and you now have red handled pipe ornament.

This really ought not be a difficult concept for even you to understand?

Now if you live in a soft water area which particularly active water,
you may also get non DZR fittings fail due to that factor. However you
would expect to see the failures in all kinds of fittings, not just gate
valves. Bib taps / stopcocks / float valves etc would also suffer - even
your humble compression straight and tee.

Since I have never had to deal with a gate valve in a soft water area, I
will pass no further comment on if they are actually more crap than
normal in these circumstances. However since under normal circumstances
they are crap before you get to worrying about other failure modes, its
a moot point.




--
Cheers,

John.

/================================================== ===============\
| Internode Ltd - http://www.internode.co.uk |
|-----------------------------------------------------------------|
| John Rumm - john(at)internode(dot)co(dot)uk |
\================================================= ================/

On Friday, 30 September 2016 23:26:59 UTC+1, John Rumm wrote:
On 30/09/2016 17:14, harry wrote:
On Tuesday, 27 September 2016 22:28:56 UTC+1, John Rumm wrote:


DZR gate valves fail in exactly the same way, and for the same reasons
as "normal" ones.

How can they as there is no zinc in them?

The failure is not caused by lack of zinc. Its a result of them being
designed by a moron.

Gate valves fail because the gate recess fills with crap: like hard
water scale, magnetite, rust, particulates etc. This makes them harder
to close, and also ensures that the gate will not seat correctly, thus
letting by.

The extra friction / misalignment on the gate also causes it to jam and
get stuck in the recess. The tap mechanism being made from cheese in the
first place is then not man enough to withdraw the gate. The spindle
snaps internally, and you now have red handled pipe ornament.

This really ought not be a difficult concept for even you to understand?

Now if you live in a soft water area which particularly active water,
you may also get non DZR fittings fail due to that factor. However you
would expect to see the failures in all kinds of fittings, not just gate
valves. Bib taps / stopcocks / float valves etc would also suffer - even
your humble compression straight and tee.

Since I have never had to deal with a gate valve in a soft water area, I
will pass no further comment on if they are actually more crap than
normal in these circumstances. However since under normal circumstances
they are crap before you get to worrying about other failure modes, its
a moot point.




The solution ****-fer-brains is to install it with the handle down.
Al valves can be affected by limescale.

On Sat, 01 Oct 2016 00:25:49 -0700, harry wrote:

On Friday, 30 September 2016 23:26:59 UTC+1, John Rumm wrote:
On 30/09/2016 17:14, harry wrote:
On Tuesday, 27 September 2016 22:28:56 UTC+1, John Rumm wrote:


DZR gate valves fail in exactly the same way, and for the same
reasons as "normal" ones.

How can they as there is no zinc in them?

The failure is not caused by lack of zinc. Its a result of them being
designed by a moron.

Gate valves fail because the gate recess fills with crap: like hard
water scale, magnetite, rust, particulates etc. This makes them harder
to close, and also ensures that the gate will not seat correctly, thus
letting by.

The extra friction / misalignment on the gate also causes it to jam and
get stuck in the recess. The tap mechanism being made from cheese in
the first place is then not man enough to withdraw the gate. The
spindle snaps internally, and you now have red handled pipe ornament.

This really ought not be a difficult concept for even you to
understand?

Now if you live in a soft water area which particularly active water,
you may also get non DZR fittings fail due to that factor. However you
would expect to see the failures in all kinds of fittings, not just
gate valves. Bib taps / stopcocks / float valves etc would also suffer
- even your humble compression straight and tee.

Since I have never had to deal with a gate valve in a soft water area,
I will pass no further comment on if they are actually more crap than
normal in these circumstances. However since under normal circumstances
they are crap before you get to worrying about other failure modes, its
a moot point.




The solution ****-fer-brains is to install it with the handle down.
Al valves can be affected by limescale.

I'd love to see you do that on a vertical run.



--
My posts are my copyright and if @diy_forums or Home Owners' Hub
wish to copy them they can pay me £1 a message.
Use the BIG mirror service in the UK: http://www.mirrorservice.org
*lightning surge protection* - a w_tom conductor

On 01/10/2016 08:25, harry wrote:
On Friday, 30 September 2016 23:26:59 UTC+1, John Rumm wrote:
On 30/09/2016 17:14, harry wrote:
On Tuesday, 27 September 2016 22:28:56 UTC+1, John Rumm wrote:


DZR gate valves fail in exactly the same way, and for the same reasons
as "normal" ones.

How can they as there is no zinc in them?

The failure is not caused by lack of zinc. Its a result of them being
designed by a moron.

Gate valves fail because the gate recess fills with crap: like hard
water scale, magnetite, rust, particulates etc. This makes them harder
to close, and also ensures that the gate will not seat correctly, thus
letting by.

The extra friction / misalignment on the gate also causes it to jam and
get stuck in the recess. The tap mechanism being made from cheese in the
first place is then not man enough to withdraw the gate. The spindle
snaps internally, and you now have red handled pipe ornament.

This really ought not be a difficult concept for even you to understand?

Now if you live in a soft water area which particularly active water,
you may also get non DZR fittings fail due to that factor. However you
would expect to see the failures in all kinds of fittings, not just gate
valves. Bib taps / stopcocks / float valves etc would also suffer - even
your humble compression straight and tee.

Since I have never had to deal with a gate valve in a soft water area, I
will pass no further comment on if they are actually more crap than
normal in these circumstances. However since under normal circumstances
they are crap before you get to worrying about other failure modes, its
a moot point.




The solution ****-fer-brains is to install it with the handle down.
Al valves can be affected by limescale.

Yeah right...

The one that failed the other day was on a vertical pipe run. How you
going to do that Sherlock?

Also why don't you do a quick lap of the country and fix all those
millions already installed the "wrong way up".

What kind of dimwit (no need to answer), would install a tap so you
can't easily operate it, just in the hope that it makes a bad design
less bad, when you could just install a better tap in the first place?


--
Cheers,

John.

/================================================== ===============\
| Internode Ltd - http://www.internode.co.uk |
|-----------------------------------------------------------------|
| John Rumm - john(at)internode(dot)co(dot)uk |
\================================================= ================/

On Saturday, 1 October 2016 09:54:42 UTC+1, Bob Eager wrote:
On Sat, 01 Oct 2016 00:25:49 -0700, harry wrote:

On Friday, 30 September 2016 23:26:59 UTC+1, John Rumm wrote:
On 30/09/2016 17:14, harry wrote:
On Tuesday, 27 September 2016 22:28:56 UTC+1, John Rumm wrote:


DZR gate valves fail in exactly the same way, and for the same
reasons as "normal" ones.

How can they as there is no zinc in them?

The failure is not caused by lack of zinc. Its a result of them being
designed by a moron.

Gate valves fail because the gate recess fills with crap: like hard
water scale, magnetite, rust, particulates etc. This makes them harder
to close, and also ensures that the gate will not seat correctly, thus
letting by.

The extra friction / misalignment on the gate also causes it to jam and
get stuck in the recess. The tap mechanism being made from cheese in
the first place is then not man enough to withdraw the gate. The
spindle snaps internally, and you now have red handled pipe ornament.

This really ought not be a difficult concept for even you to
understand?

Now if you live in a soft water area which particularly active water,
you may also get non DZR fittings fail due to that factor. However you
would expect to see the failures in all kinds of fittings, not just
gate valves. Bib taps / stopcocks / float valves etc would also suffer
- even your humble compression straight and tee.

Since I have never had to deal with a gate valve in a soft water area,
I will pass no further comment on if they are actually more crap than
normal in these circumstances. However since under normal circumstances
they are crap before you get to worrying about other failure modes, its
a moot point.




The solution ****-fer-brains is to install it with the handle down.
Al valves can be affected by limescale.

I'd love to see you do that on a vertical run.

If the pipe is vertical, crap can't fall into the recess.

Taper wedge gate valves rarely shut off tight as the angles of the obturating plate and the seat are very difficult to match exactly.
So people often overtighten them so overloading the threads.
This too can lead to failure.

If the metal looks copper coloured on the failure point, then the problem is de-zincification.

If not, then the problem is overtightening.

On 2016-09-30, John Rumm wrote:

On 30/09/2016 10:06, Adam Funk wrote:
On 2016-09-25, John Rumm wrote:

On 24/09/2016 23:45, Fredxxx wrote:

Most systems I have come across don't have any means to drain the header
tank to help replacing the gate valve. Was it a case of syphoning water
out of the header tank or an otherwise easy job?

I did not bother draining - I have a couple of conical rubber bungs[1]

We poked one into the outlet of the cold cistern, and the other into the
vent pipe from the cylinder over the cistern. That meant we only lost a
few feet of pipe's worth of water.

[1] Like:

https://www.cityplumbing.co.uk/Regin...egr05/p/581501

You can either poke the end in a pipe, or the inside of the bungs are
hollow, with a flange at the top, so they can be forced over the end of
a pipe as well.

Looks too simple to work! ;-)

How do those work for changing radiator valves? It seems to me you're
still going to spray water between unscrewing the old valve & getting
the bung in, & again between removing the bung & screwing the new
valve together.

They are not primarily intended to be used on the rad tails themselves.
They are used in vented CH systems to block of the Feed & Expansion
connection to/from the CH header tank, and also the CH vent pipe over
the tank. Once that is done, you have created an air lock that makes it
harder for water to escape.

So say you wanted to change a rad valve, you would stick the plugs into
the expansion tank/vent pipe, and then turn off both rad taps. Now drain
just that rad. Uncouple the valve you want to change from the rad, and
now you can remove it from the pipe. You will get a small amount of
spillage - but the whole system will not be able to drain out of the
open pipe, because its sealed and air can not enter elsewhere to let the
water out.

Doh. Got it.

On 04/10/16 10:07, Adam Funk wrote:
On 2016-09-30, John Rumm wrote:

On 30/09/2016 10:06, Adam Funk wrote:
On 2016-09-25, John Rumm wrote:

On 24/09/2016 23:45, Fredxxx wrote:

Most systems I have come across don't have any means to drain the header
tank to help replacing the gate valve. Was it a case of syphoning water
out of the header tank or an otherwise easy job?

I did not bother draining - I have a couple of conical rubber bungs[1]

We poked one into the outlet of the cold cistern, and the other into the
vent pipe from the cylinder over the cistern. That meant we only lost a
few feet of pipe's worth of water.

[1] Like:

https://www.cityplumbing.co.uk/Regin...egr05/p/581501

You can either poke the end in a pipe, or the inside of the bungs are
hollow, with a flange at the top, so they can be forced over the end of
a pipe as well.

Looks too simple to work! ;-)

How do those work for changing radiator valves? It seems to me you're
still going to spray water between unscrewing the old valve & getting
the bung in, & again between removing the bung & screwing the new
valve together.

They are not primarily intended to be used on the rad tails themselves.
They are used in vented CH systems to block of the Feed & Expansion
connection to/from the CH header tank, and also the CH vent pipe over
the tank. Once that is done, you have created an air lock that makes it
harder for water to escape.

So say you wanted to change a rad valve, you would stick the plugs into
the expansion tank/vent pipe, and then turn off both rad taps. Now drain
just that rad. Uncouple the valve you want to change from the rad, and
now you can remove it from the pipe. You will get a small amount of
spillage - but the whole system will not be able to drain out of the
open pipe, because its sealed and air can not enter elsewhere to let the
water out.

Doh. Got it.


Well that (sealing your cold water circuit) is of course OK as far as it
goes...until your fsking wife flushes a loo, and opens a tap, and
suddenly there is an open valve allowing air into the whole hot AND cold
water system and dumping the entire contents of the pressurized hot
water tank on your feet.



--
"When a true genius appears in the world, you may know him by this sign,
that the dunces are all in confederacy against him."

Jonathan Swift.