What's my incoming water pipe?

[Ben Blaukopf]

It's black, plastic, and 21.5mm (yup, 21.5, I checked my calipers on some 22mm copper). The stopcock uses a 22mm compression nut to connect to it.

a) What is this pipe? b) Can I use a freezing kit on it to change the stopcock? (no stopcock in the street)

After the incomer I've got a immensely wiggly stopcock with integral drain valve, then a load of 15mm including a meter. The meter itself has

22mm connections with 22-15 reducers each side.

Given I currently get a little over 20lpm (as measured by opening the kitchen tap, and flushing a toilet to drain off the cold tank), I'm hoping that replacing with 22mm where possible and a fullbore stopcock should make it worthwhile installing a heatbank or megaflo.

Ben

[Andy Wade]

That's old half-inch polyethylene (known variously as polythene, alkathene, or LDPE).

turn up a relevant previous thread on the subject.

Someone else can answer your question about using a freezing kit on it...

[Set Square]

It actually has the same OD as a 3/4" copper pipe* - which is just slightly less than 22mm. As with genuine 3/4" copper pipe, 22mm compression fittings can be used with a special olive. You may find that it's a 3/4" compression fitting - rather than 22mm - if it's several decades old.

• 3/4" is the nominal bore, so the OD is more than this. The plastic pipe will have a smaller bore than 3/4" copper pipe, because the wall thickness is greater.

[Rick]

I belive you will find the water board can switch it off for you, so you can change your stop c*ck. There may be some rules about needing a shutoff in the street.

As to freezing it, I wouldn't. If the freezing goes wrong, there is absolutly no back out plan. My experience suggestes that putting a new fixing on the end of a flowing mains preasure pipe is not possible.

Rick

[Andy Hall]

You can if it's turned on. Water will flow through the new fitting making it possible to attach it, then you can turn it off.

Makes a mess of course.

[Mathew Newton]

Ours (Bristol/Wessex Water) wouldn't. They said that the only way we'd get our water turned off is if there was a leak and they would then turn off the whole street. They actually sent a guy out to look in the street (Victorian terraced) to see what options there were.

I shall be replacing our house stopcock soon and so I am looking at ways of avoiding the ticking-timebomb of freezing the pipe. My latest idea is to phone the water board up and telling them there *will* be a leak at whatever time, coinciding with me cutting the current stopcock off... ;-)

Mathew

[Ed Sirett]

The tool to have (I've not got one but I've seen it used once) is like a pair of black-smiths tongues with rounded faces this can be used crush lead pipe shut and reopen it after. It will also work on plastic but has to be held fast for duration.