Plumbing question (stopcock and plastic water main)

If it is a modern 25mm MDPE pipe then I don't think you can safely fix it in 28mm copper compression joint, though I am hardly an expert. I tried to research this doing my own stopcock and the choice seemed to lie between getting a stopcock with a 25mm MDPE fitting on one side and

Or getting a decent 22mm compression ball valve and a 25mm MDPE to 22mm adapter. I don't think you can use a brass 22mm tube in a Hep2o pushfit fitting because it is not soft enough for the grips, so I used a Pegler compression fitting ball valve rather than a Hep2o one.

If iyour pipe is an old Imperial size then I think you can get special inserts (or dual fit inserts) for some 25mm MDPE fittings, but I don't actually know as I put in a new pipe.

PS I don't think a compression olive actually indents the brass 22mm tail of the adapter, so I would arrange that there is a mechanical block to separation of this joint when mounting the incoming pipe and the stopcock.

Roger Hayter

As a side issue, with a very well stuck tap in the main coming into the house, what is the best plan to attempt to move it. the tap itself appears not to be mounted, just suspended on the pipework under the floor. Bit of a bodge. I have had bad experiences before where the shaft has snapped off and leaked when you put some moles on the two bits to turn them. Is it worth treating with some oil first or is it more likely that the lime scale build up has just ceazed it? Can one turn the water off at the meter in the road these days? Its one of those new fangled electronic ones that communicates with a remote thingy held by the reader. Brian

It's fairly standard to have the stopcock floating - fine on rigid pipework but not in all cases.

Standard advice on how to free a stopcock is to temporarily remove the stuffing gland nut and run some penetrating oil around the shaft - it didn't help me.

Yes, the water can be turned off at the meter.