22mm water supply pipe

[Cello]

Tried to replace a (brass, compression) stoptap at my daughter's house (the house is approx. 35 years old) in Tamworth. Bought a standard 20mm to 15mm stoptap. However, the original stoptap has a 22mm bore on the inlet side, not 20 mm and the new stoptap does not fit. Checked with two Lichfield plumbers merchants and was told that plastic water supply pipes are always 20mm in external diameter (both black and blue pipes) but this clearly does not apply to the house in Tamworth. The (black) water supply plastic pipe is definitely 22mm external diameter and will not fit into a 20 mm standard filling. It looks like a 22mm fitting intended for copper pipe would fit. Is this an acceptable alternative? Also, has anyone else come across 22mm water supply pipe like this? Thanks, in anticipation of your help.

 

[basildog]

Your pipe will be old black polyethylene pipe and either class c or d most likely !
Could well be an old imperial size although may seem to be 22 mm probably 21.5 mm
Plasson and Philimac both make conversion kits but you may need to buy a few or take an offfcut with you ?
Go to a merchant that knows their stuff as There is definately other sizes .
It used to be easy round here as we had a local supply depot for local water board nearby and anything you could not get from merchants they always had one ! Due to cutbacks those days have long gone I am afraid !

 

[kimbo]

You can get universal underground fittings that cover a range of sizes for any tipe of pipe or you may find it is 3/4 so yoh can just buy a 3/4 olive and a 22mm fitting with an insert

 

[PlumbBobBob]

i agree with the others, just get a 22mm stopcock with a 3/4 olive for the inlet pipe and a reducer set down to 15mm for the outlet

 

[basildog]

i agree with the others, just get a 22mm stopcock with a 3/4 olive for the inlet pipe and a reducer set down to 15mm for the outlet

I would use an insert in the old pipe if possible as do not trust them without !

 

[Ray Stafford]

There are several grades and duties of black polyethylene, used by different water boards at different points in time. Solutions that work on some black pipe sometimes don't work on a seemingly identical pipe elsewhere.

If you can expose enough to cut some off (including the coloured writing on the side) and take it to your local independent merchant, they will almost certainly have come across it before. This is where local knowledge is irreplaceable.

 

[Killy Bing]

There are several grades and duties of black polyethylene, used by different water boards at different points in time. Solutions that work on some black pipe sometimes don't work on a seemingly identical pipe elsewhere.

If you can expose enough to cut some off (including the coloured writing on the side) and take it to your local independent merchant, they will almost certainly have come across it before. This is where local knowledge is irreplaceable.

i snip off 20 mm and then go raid Williams imperial reducers reducers

 

[Cello]

Many thanks for all the replies - very helpful!

 

[WHPES]

Leave the stopcock in place and fit another one after it.

Modern black pipes are 20mm but if the house is over 20 years old they will be some sort of 3/4 inch pipe and there were several different types with different wall thicknesses. Philmac universal coupling to 20mm modern or to 22mm copper unless you are really lucky and can find a plumbers merchants that stocks a selection of imperial plastic pipe fittings (you would probably need to take a thin trimming with you).

Whatever you do, you MUST fit a sleeve inside any plastic pipe or in time the pipe may deform and the joint blow apart. You may be able to salvage the one in the old pipe (pouring boilng water over the end usually helps to get it out) else get one from a plumbers merchant. They are usually made from copper for the Imperial sized pipe.