Happy Christmas, everyone, and a quick plumbing question.

The old brass ball cock valve in the toilet cistern keeps sticking, so
the water overflows. Moving the arm by hand, it moves fairly easily but
there's a bit of resistance inside the valve, as if the slider is
jamming. Push the arm past that, and the valve shuts correctly.

I can buy a new slider later this week, when the local hardware store
reopens. In the meantime, is it a good idea to open up the valve and
stick a bit of grease inside?

GB <NOTsomeone@microsoft.invalid> wrote:
> Happy Christmas, everyone, and a quick plumbing question.
>
>
> The old brass ball cock valve in the toilet cistern keeps sticking, so
> the water overflows. Moving the arm by hand, it moves fairly easily but
> there's a bit of resistance inside the valve, as if the slider is
> jamming. Push the arm past that, and the valve shuts correctly.
>
> I can buy a new slider later this week, when the local hardware store
> reopens. In the meantime, is it a good idea to open up the valve and
> stick a bit of grease inside?
>

If you can turn the water off and remove the plunger you’ll probably find
it’s just a bit of limescale that’s the issue. I would clean up the
plunger with a scouring pad and clean the “barrel” as best you can and see
how it goes.

Tim

--
Please don't feed the trolls

GB <NOTsomeone@microsoft.invalid> wrote:
> Happy Christmas, everyone, and a quick plumbing question.
>
>
> The old brass ball cock valve in the toilet cistern keeps sticking, so
> the water overflows. Moving the arm by hand, it moves fairly easily but
> there's a bit of resistance inside the valve, as if the slider is
> jamming. Push the arm past that, and the valve shuts correctly.
>
> I can buy a new slider later this week, when the local hardware store
> reopens. In the meantime, is it a good idea to open up the valve and
> stick a bit of grease inside?
>

The most common cause for overflowing is a worn rubber washer and a simple
solution is to disengage the ball cock arm by taking out the split pin
pivot unscrewing the end cap to release the slider. Use something to jam in
the slot the arm fits into and unscrew the end retaining the rubber washer,
reverse the washer and reassemble the valve.

On 25/12/2023 13:00, Tim+ wrote:
> GB <NOTsomeone@microsoft.invalid> wrote:
>> Happy Christmas, everyone, and a quick plumbing question.
>>
>>
>> The old brass ball cock valve in the toilet cistern keeps sticking, so
>> the water overflows. Moving the arm by hand, it moves fairly easily but
>> there's a bit of resistance inside the valve, as if the slider is
>> jamming. Push the arm past that, and the valve shuts correctly.
>>
>> I can buy a new slider later this week, when the local hardware store
>> reopens. In the meantime, is it a good idea to open up the valve and
>> stick a bit of grease inside?
>>
>
> If you can turn the water off and remove the plunger you’ll probably find
> it’s just a bit of limescale that’s the issue. I would clean up the
> plunger with a scouring pad and clean the “barrel” as best you can and see
> how it goes.
>
> Tim
>

Thanks, Guys. I'll turn the mains off and see whether the valve will
come apart after all these years. :)

GB <NOTsomeone@microsoft.invalid> wrote:
> On 25/12/2023 13:00, Tim+ wrote:
>> GB <NOTsomeone@microsoft.invalid> wrote:
>>> Happy Christmas, everyone, and a quick plumbing question.
>>>
>>>
>>> The old brass ball cock valve in the toilet cistern keeps sticking, so
>>> the water overflows. Moving the arm by hand, it moves fairly easily but
>>> there's a bit of resistance inside the valve, as if the slider is
>>> jamming. Push the arm past that, and the valve shuts correctly.
>>>
>>> I can buy a new slider later this week, when the local hardware store
>>> reopens. In the meantime, is it a good idea to open up the valve and
>>> stick a bit of grease inside?
>>>
>>
>> If you can turn the water off and remove the plunger you’ll probably find
>> it’s just a bit of limescale that’s the issue. I would clean up the
>> plunger with a scouring pad and clean the “barrel” as best you can and see
>> how it goes.
>>
>> Tim
>>
>
>
> Thanks, Guys. I'll turn the mains off and see whether the valve will
> come apart after all these years. :)
>

This has got “potential plumbing disaster” written all over it. ;-)

Tim

--
Please don't feed the trolls

On Mon, 25 Dec 2023 13:01:34 -0000 (UTC), Tricky Dicky
<tricky.dicky@sky.com> wrote:

>GB <NOTsomeone@microsoft.invalid> wrote:
>> Happy Christmas, everyone, and a quick plumbing question.
>>
>>
>> The old brass ball cock valve in the toilet cistern keeps sticking, so
>> the water overflows. Moving the arm by hand, it moves fairly easily but
>> there's a bit of resistance inside the valve, as if the slider is
>> jamming. Push the arm past that, and the valve shuts correctly.
>>
>> I can buy a new slider later this week, when the local hardware store
>> reopens. In the meantime, is it a good idea to open up the valve and
>> stick a bit of grease inside?
>>
>
>The most common cause for overflowing is a worn rubber washer and a simple
>solution is to disengage the ball cock arm by taking out the split pin
>pivot unscrewing the end cap to release the slider. Use something to jam in
>the slot the arm fits into and unscrew the end retaining the rubber washer,
>reverse the washer and reassemble the valve.

Unless you find that you'd done that ten years ago and completely
forgotten, and the imprint of the previous overturn is still visible.
New washers are easily enough come by, though.

--
Chris

On 25/12/2023 13:55, Tim+ wrote:
> GB <NOTsomeone@microsoft.invalid> wrote:
>> On 25/12/2023 13:00, Tim+ wrote:
>>> GB <NOTsomeone@microsoft.invalid> wrote:
>>>> Happy Christmas, everyone, and a quick plumbing question.
>>>>
>>>>
>>>> The old brass ball cock valve in the toilet cistern keeps sticking, so
>>>> the water overflows. Moving the arm by hand, it moves fairly easily but
>>>> there's a bit of resistance inside the valve, as if the slider is
>>>> jamming. Push the arm past that, and the valve shuts correctly.
>>>>
>>>> I can buy a new slider later this week, when the local hardware store
>>>> reopens. In the meantime, is it a good idea to open up the valve and
>>>> stick a bit of grease inside?
>>>>
>>>
>>> If you can turn the water off and remove the plunger you’ll probably find
>>> it’s just a bit of limescale that’s the issue. I would clean up the
>>> plunger with a scouring pad and clean the “barrel” as best you can and see
>>> how it goes.
>>>
>>> Tim
>>>
>>
>>
>> Thanks, Guys. I'll turn the mains off and see whether the valve will
>> come apart after all these years. :)
>>
>
> This has got “potential plumbing disaster” written all over it. ;-)
>

There's no isolation valve, so I'll leave it until tomorrow so that I
can get a replacement ball valve if needed.
> Tim
>

Tim+ <timdownieuk@yahoo.co.youkay> wrote:
> GB <NOTsomeone@microsoft.invalid> wrote:
>> On 25/12/2023 13:00, Tim+ wrote:
>>> GB <NOTsomeone@microsoft.invalid> wrote:
>>>> Happy Christmas, everyone, and a quick plumbing question.
>>>>
>>>>
>>>> The old brass ball cock valve in the toilet cistern keeps sticking, so
>>>> the water overflows. Moving the arm by hand, it moves fairly easily but
>>>> there's a bit of resistance inside the valve, as if the slider is
>>>> jamming. Push the arm past that, and the valve shuts correctly.
>>>>
>>>> I can buy a new slider later this week, when the local hardware store
>>>> reopens. In the meantime, is it a good idea to open up the valve and
>>>> stick a bit of grease inside?
>>>>
>>>
>>> If you can turn the water off and remove the plunger you’ll probably find
>>> it’s just a bit of limescale that’s the issue. I would clean up the
>>> plunger with a scouring pad and clean the “barrel” as best you can and see
>>> how it goes.

>> Thanks, Guys. I'll turn the mains off and see whether the valve will
>> come apart after all these years. :)

> This has got “potential plumbing disaster” written all over it. ;-)

> Tim

On Christmas Day shouldn’t that be ‘…potential expensive plumbing
disaster’? :-(

Good luck to the OP!

--
Spike

GB wrote:

> The old brass ball cock valve in the toilet cistern keeps sticking, so
> the water overflows.

It's not freezing out, so no danger of it creating an ice-rink.

If you've survived like that that till now, I'd leave it until the
plumbers merchants are open again before tackling it ...

On 25/12/2023 16:15, Andy Burns wrote:
> GB wrote:
>
>> The old brass ball cock valve in the toilet cistern keeps sticking, so
>> the water overflows.
>
> It's not freezing out, so no danger of it creating an ice-rink.
>
> If you've survived like that that till now, I'd leave it until the
> plumbers merchants are open again before tackling it ...
>

Yes. I thought about it, and came to the same conclusion.

I've kept the lid off the cistern, so I just give the arm a yank and the
water shuts off. It's only mildly inconvenient.

The shop staff are taking a well earned break until Wednesday.

GB <NOTsomeone@microsoft.invalid> wrote:
> On 25/12/2023 13:55, Tim+ wrote:
>> GB <NOTsomeone@microsoft.invalid> wrote:
>>> On 25/12/2023 13:00, Tim+ wrote:
>>>> GB <NOTsomeone@microsoft.invalid> wrote:
>>>>> Happy Christmas, everyone, and a quick plumbing question.
>>>>>
>>>>>
>>>>> The old brass ball cock valve in the toilet cistern keeps sticking, so
>>>>> the water overflows. Moving the arm by hand, it moves fairly easily but
>>>>> there's a bit of resistance inside the valve, as if the slider is
>>>>> jamming. Push the arm past that, and the valve shuts correctly.
>>>>>
>>>>> I can buy a new slider later this week, when the local hardware store
>>>>> reopens. In the meantime, is it a good idea to open up the valve and
>>>>> stick a bit of grease inside?
>>>>>
>>>>
>>>> If you can turn the water off and remove the plunger you’ll probably find
>>>> it’s just a bit of limescale that’s the issue. I would clean up the
>>>> plunger with a scouring pad and clean the “barrel” as best you can and see
>>>> how it goes.
>>>>
>>>> Tim
>>>>
>>>
>>>
>>> Thanks, Guys. I'll turn the mains off and see whether the valve will
>>> come apart after all these years. :)
>>>
>>
>> This has got “potential plumbing disaster” written all over it. ;-)
>>
>
> There's no isolation valve, so I'll leave it until tomorrow so that I
> can get a replacement ball valve if needed.

Wise. ;-)

Tim

--
Please don't feed the trolls

On Mon, 25 Dec 2023 16:21:31 +0000, GB <NOTsomeone@microsoft.invalid>
wrote:
>On 25/12/2023 16:15, Andy Burns wrote:
>> GB wrote:
>>
>>> The old brass ball cock valve in the toilet cistern keeps sticking, so
>>> the water overflows.
>>
>> It's not freezing out, so no danger of it creating an ice-rink.
>>
>> If you've survived like that that till now, I'd leave it until the
>> plumbers merchants are open again before tackling it ...
>>
>
>
>Yes. I thought about it, and came to the same conclusion.
>
>I've kept the lid off the cistern, so I just give the arm a yank and the
>water shuts off. It's only mildly inconvenient.
>
>The shop staff are taking a well earned break until Wednesday.
One thing to check is whether the arm between the pivot and the ball
is bent. If it's been bent down to make the water level lower, I've
found that the ball can create a sideways force on the valve making it
less free.
--
Dave W

On 25/12/2023 12:44, GB wrote:
> Happy Christmas, everyone, and a quick plumbing question.
>
>
> The old brass ball cock valve in the toilet cistern keeps sticking, so
> the water overflows. Moving the arm by hand, it moves fairly easily but
> there's a bit of resistance inside the valve, as if the slider is
> jamming. Push the arm past that, and the valve shuts correctly.
>
> I can buy a new slider later this week, when the local hardware store
> reopens. In the meantime, is it a good idea to open up the valve and
> stick a bit of grease inside?

You probably need to replace the whole inlet mechanism - in which case
replace it with a Torbeck-type valve similar to
https://www.toolstation.com/torbeck-float-fill-valve/p42876?utm_source=googleshopping&utm_medium=feed&utm_campaign=googleshoppingfeed&mkwid=_dc&pcrid=null&pkw=null&pmt=null&gad_source=1&gclid=Cj0KCQiA7aSsBhCiARIsALFvovyhqUeBC3WImnBIsX7Nt3Cv4sTRO_doG-bqhE53ueFaBW278O1O5cAaAmykEALw_wcB&gclsrc=aw.ds
rather than like for like.

The one linked above is side entry, but you can get a bottom entry
version if that's what your cistern uses.

While you've got the water turned off, fit an isolation valve to make
life easier in future.
--
Cheers,
Roger

In message <umc176$32enu$1@dont-email.me>, GB
<NOTsomeone@microsoft.invalid> writes
>On 25/12/2023 13:00, Tim+ wrote:
>> GB <NOTsomeone@microsoft.invalid> wrote:
>>> Happy Christmas, everyone, and a quick plumbing question.
>>>
>>>
>>> The old brass ball cock valve in the toilet cistern keeps sticking, so
>>> the water overflows. Moving the arm by hand, it moves fairly easily but
>>> there's a bit of resistance inside the valve, as if the slider is
>>> jamming. Push the arm past that, and the valve shuts correctly.
>>>
>>> I can buy a new slider later this week, when the local hardware store
>>> reopens. In the meantime, is it a good idea to open up the valve and
>>> stick a bit of grease inside?
>>>
>> If you can turn the water off and remove the plunger you’ll
>>probably find
>> it’s just a bit of limescale that’s the issue. I would clean up the
>> plunger with a scouring pad and clean the “barrel” as best you
>>can and see
>> how it goes.
>> Tim
>>
>
>
>Thanks, Guys. I'll turn the mains off and see whether the valve will
>come apart after all these years. :)
>
If it's the normal old-fashioned type, don't mess about (like I found
myself doing recently), and simply buy a replacement. Mine was
physically identical to the 50 year old one, and cost £11 (without the
ball).
--
Ian
Aims and ambitions are neither attainments nor achievements

In message
<51713340.725215923.069940.timdownieuk-yahoo.co.youkay@news.individual.ne
t>, Tim+ <timdownieuk@yahoo.co.youkay> writes
>GB <NOTsomeone@microsoft.invalid> wrote:
>> On 25/12/2023 13:55, Tim+ wrote:
>>> GB <NOTsomeone@microsoft.invalid> wrote:
>>>> On 25/12/2023 13:00, Tim+ wrote:
>>>>> GB <NOTsomeone@microsoft.invalid> wrote:
>>>>>> Happy Christmas, everyone, and a quick plumbing question.
>>>>>>
>>>>>>
>>>>>> The old brass ball cock valve in the toilet cistern keeps sticking, so
>>>>>> the water overflows. Moving the arm by hand, it moves fairly easily but
>>>>>> there's a bit of resistance inside the valve, as if the slider is
>>>>>> jamming. Push the arm past that, and the valve shuts correctly.
>>>>>>
>>>>>> I can buy a new slider later this week, when the local hardware store
>>>>>> reopens. In the meantime, is it a good idea to open up the valve and
>>>>>> stick a bit of grease inside?
>>>>>>
>>>>>
>>>>> If you can turn the water off and remove the plunger you’ll
>>>>>probably find
>>>>> it’s just a bit of limescale that’s the issue. I would clean up the
>>>>> plunger with a scouring pad and clean the “barrel” as best you
>>>>>can and see
>>>>> how it goes.
>>>>>
>>>>> Tim
>>>>>
>>>>
>>>>
>>>> Thanks, Guys. I'll turn the mains off and see whether the valve will
>>>> come apart after all these years. :)
>>>>
>>>
>>> This has got “potential plumbing disaster” written all over it. ;-)
>>>
>>
>> There's no isolation valve, so I'll leave it until tomorrow so that I
>> can get a replacement ball valve if needed.
>
>Wise. ;-)
>
>Tim
>
While you're at it, why not insert an isolation valve in the feed pipe?
[It's also a good opportunity to treat yourself to a £15 pipe cutter.]
--
Ian
Aims and ambitions are neither attainments nor achievements

On 25/12/2023 15:23, GB wrote:
> There's no isolation valve, so I'll leave it until tomorrow so that I
> can get a replacement ball valve if needed.

I'm late, but I'm curious. Without an isolation valve how did you fix it?

Andy

On 25/12/2023 17:06, Dave W wrote:
> On Mon, 25 Dec 2023 16:21:31 +0000, GB <NOTsomeone@microsoft.invalid>
> wrote:
>
>> On 25/12/2023 16:15, Andy Burns wrote:
>>> GB wrote:
>>>
>>>> The old brass ball cock valve in the toilet cistern keeps sticking, so
>>>> the water overflows.
>>>
>>> It's not freezing out, so no danger of it creating an ice-rink.
>>>
>>> If you've survived like that that till now, I'd leave it until the
>>> plumbers merchants are open again before tackling it ...
>>>
>>
>>
>> Yes. I thought about it, and came to the same conclusion.
>>
>> I've kept the lid off the cistern, so I just give the arm a yank and the
>> water shuts off. It's only mildly inconvenient.
>>
>> The shop staff are taking a well earned break until Wednesday.
>
> One thing to check is whether the arm between the pivot and the ball
> is bent. If it's been bent down to make the water level lower, I've
> found that the ball can create a sideways force on the valve making it
> less free.

Rarely, the float can develop a leak, especially the really
old metal ones, so that they slowly sit lower in the water.

Complete replacement lever arms and valves are cheap as chips.

On 29/12/2023 17:35, Vir Campestris wrote:
> On 25/12/2023 15:23, GB wrote:
>> There's no isolation valve, so I'll leave it until tomorrow so that I
>> can get a replacement ball valve if needed.
>
> I'm late, but I'm curious. Without an isolation valve how did you fix it?
>
> Andy

Presumably by turning the water off for the whole house at the stop
cock. Not half as convenient as being able to isolate a single device.
--
Cheers,
Roger

On 25/12/2023 13:48, GB wrote:
> Thanks, Guys. I'll turn the mains off and see whether the valve will
> come apart after all these years. 🙂

A time opportunity, to fit an inline isolation valve, for the few pence
they cost. You can then start the job by fitting it, turning it off, and
the general water back on.

Kettle descaler, acetic acid, or even lemon juice will remove the
buildup of limescale easily, without damage.

On 29/12/2023 22:55, Harry Bloomfield Esq wrote:
> On 25/12/2023 13:48, GB wrote:
>> Thanks, Guys. I'll turn the mains off and see whether the valve will
>> come apart after all these years. 🙂
>
> A time opportunity, to fit an inline isolation valve, for the few pence
> they cost. You can then start the job by fitting it, turning it off, and
> the general water back on.
>
> Kettle descaler, acetic acid, or even lemon juice will remove the
> buildup of limescale easily, without damage.

There's no room for an isolation valve.

In the end, the job went quite smoothly. I had bought a spare ball cock
valve, but didn't need it. A new split pin would have been a good idea,
rather than straightening the old one out.

On 30/12/2023 09:24, GB wrote:
> On 29/12/2023 22:55, Harry Bloomfield Esq wrote:
>> On 25/12/2023 13:48, GB wrote:
>>> Thanks, Guys. I'll turn the mains off and see whether the valve will
>>> come apart after all these years. 🙂
>>
>> A time opportunity, to fit an inline isolation valve, for the few
>> pence they cost. You can then start the job by fitting it, turning it
>> off, and the general water back on.
>>
>> Kettle descaler, acetic acid, or even lemon juice will remove the
>> buildup of limescale easily, without damage.
>
>
> There's no room for an isolation valve.
>
> In the end, the job went quite smoothly. I had bought a spare ball cock
> valve, but didn't need it. A new split pin would have been a good idea,
> rather than straightening the old one out.

There must be room somewhere in the pipework? You can also get elbow
versions:
https://www.screwfix.com/p/flomasta-isolating-valve-15mm/741fa

On 30/12/2023 13:30, Fredxx wrote:
> On 30/12/2023 09:24, GB wrote:
>> On 29/12/2023 22:55, Harry Bloomfield Esq wrote:
>>> On 25/12/2023 13:48, GB wrote:
>>>> Thanks, Guys. I'll turn the mains off and see whether the valve will
>>>> come apart after all these years. 🙂
>>>
>>> A time opportunity, to fit an inline isolation valve, for the few
>>> pence they cost. You can then start the job by fitting it, turning it
>>> off, and the general water back on.
>>>
>>> Kettle descaler, acetic acid, or even lemon juice will remove the
>>> buildup of limescale easily, without damage.
>>
>>
>> There's no room for an isolation valve.
>>
>> In the end, the job went quite smoothly. I had bought a spare ball
>> cock valve, but didn't need it. A new split pin would have been a good
>> idea, rather than straightening the old one out.
>
> There must be room somewhere in the pipework? You can also get elbow
> versions:
>   https://www.screwfix.com/p/flomasta-isolating-valve-15mm/741fa
>

The mains pipe is boxed in next to the soil pipe. There is just under
30mm of pipe exposed between the boxing and the nut on the end of the valve.

On 30/12/2023 17:20, GB wrote:
> On 30/12/2023 13:30, Fredxx wrote:
>> On 30/12/2023 09:24, GB wrote:
>>> On 29/12/2023 22:55, Harry Bloomfield Esq wrote:
>>>> On 25/12/2023 13:48, GB wrote:
>>>>> Thanks, Guys. I'll turn the mains off and see whether the valve
>>>>> will come apart after all these years. 🙂
>>>>
>>>> A time opportunity, to fit an inline isolation valve, for the few
>>>> pence they cost. You can then start the job by fitting it, turning
>>>> it off, and the general water back on.
>>>>
>>>> Kettle descaler, acetic acid, or even lemon juice will remove the
>>>> buildup of limescale easily, without damage.
>>>
>>>
>>> There's no room for an isolation valve.
>>>
>>> In the end, the job went quite smoothly. I had bought a spare ball
>>> cock valve, but didn't need it. A new split pin would have been a
>>> good idea, rather than straightening the old one out.
>>
>> There must be room somewhere in the pipework? You can also get elbow
>> versions:
>>    https://www.screwfix.com/p/flomasta-isolating-valve-15mm/741fa
>>
>
> The mains pipe is boxed in next to the soil pipe. There is just under
> 30mm of pipe exposed between the boxing and the nut on the end of the
> valve.

I guess the other bathroom supplies are Tee'd of this mains pipe?

I suppose the most compact solution is an 15mm x 1/2" service valve:
https://www.screwfix.com/p/pegler-straight-service-valve-15mm-x-1-2-/19933

On 30/12/2023 17:28, Fredxx wrote:
> On 30/12/2023 17:20, GB wrote:
>> On 30/12/2023 13:30, Fredxx wrote:
>>> On 30/12/2023 09:24, GB wrote:
>>>> On 29/12/2023 22:55, Harry Bloomfield Esq wrote:
>>>>> On 25/12/2023 13:48, GB wrote:
>>>>>> Thanks, Guys. I'll turn the mains off and see whether the valve
>>>>>> will come apart after all these years. 🙂
>>>>>
>>>>> A time opportunity, to fit an inline isolation valve, for the few
>>>>> pence they cost. You can then start the job by fitting it, turning
>>>>> it off, and the general water back on.
>>>>>
>>>>> Kettle descaler, acetic acid, or even lemon juice will remove the
>>>>> buildup of limescale easily, without damage.
>>>>
>>>>
>>>> There's no room for an isolation valve.
>>>>
>>>> In the end, the job went quite smoothly. I had bought a spare ball
>>>> cock valve, but didn't need it. A new split pin would have been a
>>>> good idea, rather than straightening the old one out.
>>>
>>> There must be room somewhere in the pipework? You can also get elbow
>>> versions:
>>>    https://www.screwfix.com/p/flomasta-isolating-valve-15mm/741fa
>>>
>>
>> The mains pipe is boxed in next to the soil pipe. There is just under
>> 30mm of pipe exposed between the boxing and the nut on the end of the
>> valve.
>
> I guess the other bathroom supplies are Tee'd of this mains pipe?
>
> I suppose the most compact solution is an 15mm x 1/2" service valve:
>
> https://www.screwfix.com/p/pegler-straight-service-valve-15mm-x-1-2-/19933

It's 57mm long according to the Q&A.

--

Jeff

On 30/12/2023 22:16, Jeff Layman wrote:
> On 30/12/2023 17:28, Fredxx wrote:
>> On 30/12/2023 17:20, GB wrote:
>>> On 30/12/2023 13:30, Fredxx wrote:
>>>> On 30/12/2023 09:24, GB wrote:
>>>>> On 29/12/2023 22:55, Harry Bloomfield Esq wrote:
>>>>>> On 25/12/2023 13:48, GB wrote:
>>>>>>> Thanks, Guys. I'll turn the mains off and see whether the valve
>>>>>>> will come apart after all these years. 🙂
>>>>>>
>>>>>> A time opportunity, to fit an inline isolation valve, for the few
>>>>>> pence they cost. You can then start the job by fitting it, turning
>>>>>> it off, and the general water back on.
>>>>>>
>>>>>> Kettle descaler, acetic acid, or even lemon juice will remove the
>>>>>> buildup of limescale easily, without damage.
>>>>>
>>>>>
>>>>> There's no room for an isolation valve.
>>>>>
>>>>> In the end, the job went quite smoothly. I had bought a spare ball
>>>>> cock valve, but didn't need it. A new split pin would have been a
>>>>> good idea, rather than straightening the old one out.
>>>>
>>>> There must be room somewhere in the pipework? You can also get elbow
>>>> versions:
>>>>     https://www.screwfix.com/p/flomasta-isolating-valve-15mm/741fa
>>>>
>>>
>>> The mains pipe is boxed in next to the soil pipe. There is just under
>>> 30mm of pipe exposed between the boxing and the nut on the end of the
>>> valve.
>>
>> I guess the other bathroom supplies are Tee'd of this mains pipe?
>>
>> I suppose the most compact solution is an 15mm x 1/2" service valve:
>> https://www.screwfix.com/p/pegler-straight-service-valve-15mm-x-1-2-/19933
>
> It's 57mm long according to the Q&A.

So 27mm needs to be pushed into the boxing? If it's anything like mine
it will move that far, and as long as you still have access to the
service screw, Bob's your parent's sibling.