Plastic to copper

[Willibrod]

The water service pipe to my house is black plastic having an actual outside diameter of 21.4 mm. The pipe has markings “TELCON BS (kitemark) 1972 = ½” = CLASS D”. I want to replace the (in house) stopcock which has seized up, so I need an adapter to convert the plastic pipe to 15 mm copper, preferably incorporated in a
non-standard stopcock, but probably using an adapter and standard stopcock if that is the only way. I have tried a 20mm brass fitting for plastic pipe but it is not a good fit. What is the proper fitting(s) for this? Any help gratefully appreciated.

 

[PlumbBobBob]

what i have used is a 22mm stopcock onto the plastic incoming pipe then a compression reducer(three parts that fit into the 22mm fitting to take 15mm pipe) to join onto the 15mm pipe.

 

[WHPES]

Look at the philmac range (on the internet I expect) as they specialise in converting one size to another.

The fitting you want will have a 3/4" "alkathene" on one end and a 15mm push fit on the other. Just use a 15mm stopcock on the pipe

 

[Willibrod]

Thanks to steveb and WHPES. I have tried the plastic pipe in a 22mm fitting but it was too loose to give any confidence. The website Philmac looks useful and they do seem to supply a likely looking adapter. I am checking further with them. A further question I forgot about is whether this plastic pipe (having quite thick - 3.5 mm ) wall, needs an insert.
Thanks again to both.

 

[PlumbBobBob]

yes i would say it needs an insert

 

[kneeslider93]

Hope this doesn't sound too complicated and makes sense. I have used a brass female 3/4 stop tap, then inserted a 3/4 male npt to 3/4 compression fitting in one end and then a 3/4 npt male to 15mm compression fitting in the other to get over this particular problem. You definitely need a metal insert into the black plastic pipe.

 

[Gray0689]

15mm copper pipe can be used as an insert in most cases

 

[GQuigley67]

don't know if this will work but you could try an imperial olive with the 22mm compression fitting(due to the plastic pipe being old im guessing its imperial size) and it definetely needs an insert for something to compress onto.

 

[gas57]

couldent have said it better my self nice to see plumbers that no thers stuff

 

[Billy Bob Bob]

why not just fit your new stoptap above the existing one?

 

[ecowarm]

talbot do push fit for black alk http://www.stratique.com/clients/tyco/pdf/PLASTIC%20PUSHFIT%20FITTINGS/Talbot%20Pushfit%20Fittings%20Data%20Sheet.pdf and dont require inserts

 

[Willibrod]

Thanks everybody for useful advice. However, Philmac do supply an exact plastic fitting converting my 21.4mm OD plastic pipe to 3/4 BSP. They also assure me that an insert is not necessary on account of the thick (3to4mm wall thickness). Thanks also to Gasman for suggestion of simply adding new stopcock above existing one. Unfortunately very limited in room. Anyway, I think this should conclude this thread? Thanks again, it is nice to know so much expertise is readily available. Willibrod