Is this an alkathene pipe ? Size ?

[shd1970]

Happy new year all !

So my dad has just tried to turn the cold water off using the stop cock in his house to change a tap washer (no isolation valves) but evidently its not having the desired effect and the stop cock has now started to drip a little.
I'm not surprised consider the stop cock is likely 40+ years old so i'm expecting to make a visit to have to replace for him
I got him to send a photo (see attached)

From what i can see, it looks like a black alkathene pipe (you can just make it out) that looks like it has been housed in some protective pipe cover

So my thought was to :

1. remove stop cock and trim/tidy up alkathene pipe
2. fit a Philmac connector (the ones with push fit 15mm copper on the output end)
3. small length of 15mm
4. new stop cock

Approach sound about right ?

If so, can anyone confirm just what the size the alkathene pipe is likely to be please so i can get the right one, as my dads eyesight aint great and if i ask him to scrabble around on the floor, he likely wont be able to get back up again !!!

House was built in 1981

TIA !

 

[denso13]

You could leave the existing adapter on the alkathene and just change the stopcock. Much simpler.

 

[Exedon]

Almost certainly 1/2 in alkathene had a external size equivalent to 3/4 copper. Came in class C and class D (different wall thickness) so different inserts.
Bottom line as above just change stop tap get a decent one screwfix sell pegler ones.

 

[shd1970]

Denso exedon, thanks for replies
I was assuming that the lower connection would be disturbed hence assuming that I’ll end up replacing the lot and also, just personally, I’ve never been a fan of a large iron work onto plastic/alkathene

 

[Exedon]

No iron involved that's a brass connector

 

[JohnD]

Denso exedon, thanks for replies
I was assuming that the lower connection would be disturbed hence assuming that I’ll end up replacing the lot and also, just personally, I’ve never been a fan of a large iron work onto plastic/alkathene

It looks to me like you already have a stub of 15mm or 1/2" copper pipe, so if you use that, an off-the-shelf stopcock will save you a lot of trouble.

Sometimes you can swap the headworks (the moving parts) from an old to a new stopcock, which save you disturbing the connections, by undoing the large nut under the handle and spindle. Practice by taking your new stopcock apart and you will see what I mean.

I hope you have an outdoor stopcock in the garden or under the pavement (may be integral part of the water meter)

 

[ianmcd]

Personally I wouldnt go anywhere near Alcathene, unless you absolutely have to, you are just making a simple job very risky, just as already advised change the stop cock and leave the rest alone

 

[shd1970]

No iron involved that's a brass connector

thanks Exedon....my use and mention of iron work was just a lazy attempt at referring to the metal work

 

[shd1970]

It looks to me like you already have a stub of 15mm or 1/2" copper pipe, so if you use that, an off-the-shelf stopcock will save you a lot of trouble.

Sometimes you can swap the headworks (the moving parts) from an old to a new stopcock, which save you disturbing the connections, by undoing the large nut under the handle and spindle. Practice by taking your new stopcock apart and you will see what I mean.

I hope you have an outdoor stopcock in the garden or under the pavement (may be integral part of the water meter)

thanks JohnD

if my dad is correct in that when he closes the stop tap but the water doesn't shut off, what is that a sign of exactly ?
is it just a rubber washer that has likely perished or summat else ?

yes there is a stop cock at the end of his drive where we will isolate first

 

[JohnD]

You mean the one in the pic? Might be partially seized through age and lack of use.

It does them good to close and open them once a year

If you can turn off the outside stopcock, it looks to me like the old one is leaking round the spindle gland. Probably age, corrosion and tarnish have roughened it and rubbed loose when turned.

If you undo the smallest nut nearest the handle, polish up the spindle with a green pan scourer, wrap a couple of turns of PTFE tape round it, and carefully retighten the gland nut without scraping it off, it will probably stop leaking until you can make a proper replacement (or until it has to be opened and closed again, if sooner). When built, it might have been packed with greased string or fibre or something. It is easier to clean, polish, lubricate and re-seal if you take the whole headworks apart on the bench, but I don't suggest you do that as it will leave the house without water until you have finished, and something might go wrong. I like to put PTFE on the threads when reassembling to prevent it seizing again. Many plumbers disagree with me.

If you have the chance to practice with a spare old one, you will see what I mean and it will be easier next time. Sometimes the threads are seized and very difficult to undo.

 

[JohnD]

I expect it's just seizing with tarnish, corrosion, limescale etc. If you have strong hands, work it to and fro, in and out, a bit at a time and it will probably free off. No great force.

Also, found this vid about the gland. You need good spanners that are a perfect fit. You do not have to scrape out the old packing for a quick fix when you are lying on a concrete floor with a torch.

My reason for polishing up the spindle (with the water turned off), is because I think the rough old spindle wears away the packing when turned. I am a householder, not a plumber.

 

[JohnD]

And this one shows changing the headworks. Note the size is stamped on the side. It can save you taking the body of the tap off the pipes and perhaps having trouble reconnecting.

(Or, clean, lube, reseal, rewasher if you can't get a new one that fits, for example a very old one)

If you have not done it before, have a spare to hand before you start in case something goes wrong)

 

[Keithmac]

If you knacker the supply pipe you're in a world of pain!.

I got our original stop tap to seal when open and then fitted a full bore lever valve further up on some fresh copper pipe.

Sometimes best to let sleeping dogs lie..

 

[CBW]

+1 for repacking the gland. Replace if you really want/have to.