I've had 2 of the plastic stopcocks fail. I'm using them on exposed
MDPE pipe whilst I build my extension, so they are in a dusty
environment. One for the current house supply and one tee'd off for
site water with a hose on the end of it.
They have both failed to turn the water off when done up tight after
on-off cycle maybe 20 or so times. One was from Wickes, other was
philmac.
All I can think is they are hopeless against ingress of dust. The
Wickes one failed a day after some heavy dry cutting of concrete. A
hoselock tap connector was under full mains pressure due to the
stopcock failing, and had eventually popped off the end of the MDPE
and the garden was being flooded. I guess it would have popped off
when taps were turned off this morning and the static pressure had
built up suddenly.
I think I'll have to fit a copper one instead.
Simon.

On 6 Jul, 15:22, sm_jamieson  wrote:
> I've had 2 of the plastic stopcocks fail. I'm using them on exposed
> MDPE pipe whilst I build my extension, so they are in a dusty
> environment. One for the current house supply and one tee'd off for
> site water with a hose on the end of it.
> They have both failed to turn the water off when done up tight after
> on-off cycle maybe 20 or so times. One was from Wickes, other was
> philmac.
> All I can think is they are hopeless against ingress of dust. The
> Wickes one failed a day after some heavy dry cutting of concrete. A
> hoselock tap connector was under full mains pressure due to the
> stopcock failing, and had eventually popped off the end of the MDPE
> and the garden was being flooded. I guess it would have popped off
> when taps were turned off this morning and the static pressure had
> built up suddenly.
> I think I'll have to fit a copper one instead.
> Simon.

Well, changed for a metal stopcock, did a postmortem on plastic one,
the inside was like a standard tap with a nib and plastic washer.
Somehow
the washer had become detached from the nib, and slipped out of place,
preventing the tap from shutting off.
Why does this never happen to metal taps ?
I think the tolerances are a bit sloppy in the plastic ones.
And it was nothing to do with dust at all.
I'm not impressed.
Simon.

"sm_jamieson"  wrote in message 
news:007dc783-cc26-4ba0-ab5c-4514d9a37e37@k37g2000hsf.googlegroups.com...
> On 6 Jul, 15:22, sm_jamieson  wrote:
>> I've had 2 of the plastic stopcocks fail. I'm using them on exposed
>> MDPE pipe whilst I build my extension, so they are in a dusty
>> environment. One for the current house supply and one tee'd off for
>> site water with a hose on the end of it.
>> They have both failed to turn the water off when done up tight after
>> on-off cycle maybe 20 or so times. One was from Wickes, other was
>> philmac.
>> All I can think is they are hopeless against ingress of dust. The
>> Wickes one failed a day after some heavy dry cutting of concrete. A
>> hoselock tap connector was under full mains pressure due to the
>> stopcock failing, and had eventually popped off the end of the MDPE
>> and the garden was being flooded. I guess it would have popped off
>> when taps were turned off this morning and the static pressure had
>> built up suddenly.
>> I think I'll have to fit a copper one instead.
>> Simon.
>
> Well, changed for a metal stopcock, did a postmortem on plastic one,
> the inside was like a standard tap with a nib and plastic washer.
> Somehow
> the washer had become detached from the nib, and slipped out of place,
> preventing the tap from shutting off.
> Why does this never happen to metal taps ?
> I think the tolerances are a bit sloppy in the plastic ones.
> And it was nothing to do with dust at all.
> I'm not impressed.

Don't be offended by the question :o)  but it is as well to check - it was 
fitted the right way round wasn't it?


-- 
Bob Mannix
(anti-spam is as easy as 1-2-3 - not

On 7 Jul, 08:02, "Bob Mannix"  wrote:
> "sm_jamieson"  wrote in message
>
> news:007dc783-cc26-4ba0-ab5c-4514d9a37e37@k37g2000hsf.googlegroups.com...
>
>
>
> > On 6 Jul, 15:22, sm_jamieson  wrote:
> >> I've had 2 of the plastic stopcocks fail. I'm using them on exposed
> >> MDPE pipe whilst I build my extension, so they are in a dusty
> >> environment. One for the current house supply and one tee'd off for
> >> site water with a hose on the end of it.
> >> They have both failed to turn the water off when done up tight after
> >> on-off cycle maybe 20 or so times. One was from Wickes, other was
> >> philmac.
> >> All I can think is they are hopeless against ingress of dust. The
> >> Wickes one failed a day after some heavy dry cutting of concrete. A
> >> hoselock tap connector was under full mains pressure due to the
> >> stopcock failing, and had eventually popped off the end of the MDPE
> >> and the garden was being flooded. I guess it would have popped off
> >> when taps were turned off this morning and the static pressure had
> >> built up suddenly.
> >> I think I'll have to fit a copper one instead.
> >> Simon.
>
> > Well, changed for a metal stopcock, did a postmortem on plastic one,
> > the inside was like a standard tap with a nib and plastic washer.
> > Somehow
> > the washer had become detached from the nib, and slipped out of place,
> > preventing the tap from shutting off.
> > Why does this never happen to metal taps ?
> > I think the tolerances are a bit sloppy in the plastic ones.
> > And it was nothing to do with dust at all.
> > I'm not impressed.
>
> Don't be offended by the question :o)  but it is as well to check - it was
> fitted the right way round wasn't it?
>

No fair comment !
I don't remember there being an arrow on it (and I usually look for
one), but I'll certainly check. Let you know tonight.
I think the first one that failed was due to grit/sand working its way
in since I could hear it grind as I operated it.
Other thing, some air came through the pipe the other day after it
being off at 4 in the morning (work somewhere done the line I
presume), and this can blast quite a bit - I wonder if it could know
the washer off it's nib ?
Simon.

"sm_jamieson"  wrote in message 
news:d22df197-36b1-48a6-b916-ce70e70de21f@z66g2000hsc.googlegroups.com...
> On 7 Jul, 08:02, "Bob Mannix"  wrote:
>> "sm_jamieson"  wrote in message
>>
>> news:007dc783-cc26-4ba0-ab5c-4514d9a37e37@k37g2000hsf.googlegroups.com...
>>
>>
>>
>> > On 6 Jul, 15:22, sm_jamieson  wrote:
>> >> I've had 2 of the plastic stopcocks fail. I'm using them on exposed
>> >> MDPE pipe whilst I build my extension, so they are in a dusty
>> >> environment. One for the current house supply and one tee'd off for
>> >> site water with a hose on the end of it.
>> >> They have both failed to turn the water off when done up tight after
>> >> on-off cycle maybe 20 or so times. One was from Wickes, other was
>> >> philmac.
>> >> All I can think is they are hopeless against ingress of dust. The
>> >> Wickes one failed a day after some heavy dry cutting of concrete. A
>> >> hoselock tap connector was under full mains pressure due to the
>> >> stopcock failing, and had eventually popped off the end of the MDPE
>> >> and the garden was being flooded. I guess it would have popped off
>> >> when taps were turned off this morning and the static pressure had
>> >> built up suddenly.
>> >> I think I'll have to fit a copper one instead.
>> >> Simon.
>>
>> > Well, changed for a metal stopcock, did a postmortem on plastic one,
>> > the inside was like a standard tap with a nib and plastic washer.
>> > Somehow
>> > the washer had become detached from the nib, and slipped out of place,
>> > preventing the tap from shutting off.
>> > Why does this never happen to metal taps ?
>> > I think the tolerances are a bit sloppy in the plastic ones.
>> > And it was nothing to do with dust at all.
>> > I'm not impressed.
>>
>> Don't be offended by the question :o)  but it is as well to check - it 
>> was
>> fitted the right way round wasn't it?
>>
>
> No fair comment !
> I don't remember there being an arrow on it (and I usually look for
> one), but I'll certainly check. Let you know tonight.
> I think the first one that failed was due to grit/sand working its way
> in since I could hear it grind as I operated it.
> Other thing, some air came through the pipe the other day after it
> being off at 4 in the morning (work somewhere done the line I
> presume), and this can blast quite a bit - I wonder if it could know
> the washer off it's nib ?

Well, that sort of thing was my concern - if the flow is past the washer in 
a sense that would pull it off the nib then maybe.. (and it would be the 
wrong way round). If the flow pushes against the washer so as to force it 
onto the nib (as in a corrctly installed valve) it's hard to see how it 
would come off!

In my previous house the stopcock was the wrong way round - the washer nib 
was a sliding fit in the tap head and had come loose and so just got forced 
closed when you opened the tap - mine would shut off but not open properly. 
I turned it round and it was fine.


-- 
Bob Mannix
(anti-spam is as easy as 1-2-3 - not)

On 7 Jul, 11:31, "Bob Mannix"  wrote:
> "sm_jamieson"  wrote in message
>
> news:d22df197-36b1-48a6-b916-ce70e70de21f@z66g2000hsc.googlegroups.com...
>
>
>
> > On 7 Jul, 08:02, "Bob Mannix"  wrote:
> >> "sm_jamieson"  wrote in message
>
> >>news:007dc783-cc26-4ba0-ab5c-4514d9a37e37@k37g2000hsf.googlegroups.com...
>
> >> > On 6 Jul, 15:22, sm_jamieson  wrote:
> >> >> I've had 2 of the plastic stopcocks fail. I'm using them on exposed
> >> >> MDPE pipe whilst I build my extension, so they are in a dusty
> >> >> environment. One for the current house supply and one tee'd off for
> >> >> site water with a hose on the end of it.
> >> >> They have both failed to turn the water off when done up tight after
> >> >> on-off cycle maybe 20 or so times. One was from Wickes, other was
> >> >> philmac.
> >> >> All I can think is they are hopeless against ingress of dust. The
> >> >> Wickes one failed a day after some heavy dry cutting of concrete. A
> >> >> hoselock tap connector was under full mains pressure due to the
> >> >> stopcock failing, and had eventually popped off the end of the MDPE
> >> >> and the garden was being flooded. I guess it would have popped off
> >> >> when taps were turned off this morning and the static pressure had
> >> >> built up suddenly.
> >> >> I think I'll have to fit a copper one instead.
> >> >> Simon.
>
> >> > Well, changed for a metal stopcock, did a postmortem on plastic one,
> >> > the inside was like a standard tap with a nib and plastic washer.
> >> > Somehow
> >> > the washer had become detached from the nib, and slipped out of place,
> >> > preventing the tap from shutting off.
> >> > Why does this never happen to metal taps ?
> >> > I think the tolerances are a bit sloppy in the plastic ones.
> >> > And it was nothing to do with dust at all.
> >> > I'm not impressed.
>
> >> Don't be offended by the question :o)  but it is as well to check - it
> >> was
> >> fitted the right way round wasn't it?
>
> > No fair comment !
> > I don't remember there being an arrow on it (and I usually look for
> > one), but I'll certainly check. Let you know tonight.
> > I think the first one that failed was due to grit/sand working its way
> > in since I could hear it grind as I operated it.
> > Other thing, some air came through the pipe the other day after it
> > being off at 4 in the morning (work somewhere done the line I
> > presume), and this can blast quite a bit - I wonder if it could know
> > the washer off it's nib ?
>
> Well, that sort of thing was my concern - if the flow is past the washer in
> a sense that would pull it off the nib then maybe.. (and it would be the
> wrong way round). If the flow pushes against the washer so as to force it
> onto the nib (as in a corrctly installed valve) it's hard to see how it
> would come off!
>
> In my previous house the stopcock was the wrong way round - the washer nib
> was a sliding fit in the tap head and had come loose and so just got forced
> closed when you opened the tap - mine would shut off but not open properly.
> I turned it round and it was fine.
>
> --
> Bob Mannix
> (anti-spam is as easy as 1-2-3 - not)

Well the metal one I fitted is definitely the correct way round - one
end is 25mm and the other 15mm !
Simon.

On 6 Jul, 18:35, sm_jamieson  wrote:
> On 6 Jul, 15:22, sm_jamieson  wrote:
>
>
>
> > I've had 2 of the plastic stopcocksfail. I'm using them on exposed
> > MDPE pipe whilst I build my extension, so they are in a dusty
> > environment. One for the current house supply and one tee'd off for
> > site water with a hose on the end of it.
> > They have both failed to turn the water off when done up tight after
> > on-off cycle maybe 20 or so times. One was from Wickes, other was
> > philmac.
> > All I can think is they are hopeless against ingress of dust. The
> > Wickes one failed a day after some heavy dry cutting of concrete. A
> > hoselock tap connector was under full mains pressure due to the
> >stopcockfailing, and had eventually popped off the end of the MDPE
> > and the garden was being flooded. I guess it would have popped off
> > when taps were turned off this morning and the static pressure had
> > built up suddenly.
> > I think I'll have to fit a copper one instead.
> > Simon.
>
> Well, changed for a metalstopcock, did a postmortem on plastic one,
> the inside was like a standard tap with a nib and plastic washer.
> Somehow
> the washer had become detached from the nib, and slipped out of place,
> preventing the tap from shutting off.
> Why does this never happen to metal taps ?
> I think the tolerances are a bit sloppy in the plastic ones.
> And it was nothing to do with dust at all.
> I'm not impressed.
> Simon.

Now done a postmortem on the other failed one, the one I thought had
grit in it.
It had what looked like quarter of a broken washer that had got onto
the plastic valve seat and
deformed it when I'd tightened the tap to try and shut it off. Who
knows where the washer came from.
Good job the stopcock had stopped it moving further up the pipe.
The stopcock next door had been changed recently so it could be
something to do with that.
The need to make a totally transparent stopcock, so you could see any
problem without removing it.
Simon.