New water main-stop cock and drain valve?

[RockyBalboa]

Installing a new water main with blue 25mm MDPE. The water company state I need a stop cock followed by a drain off valve.

Can I use a plastic stop cock such as:

https://www.toolstation.com/jg-speedfit-mdpe-stop-...

And drain off valve such as:

https://www.screwfix.com/p/jg-speedfit-15mm/12232?...

[stevensdrs]

You can't use the stopcock you have identified as it's only 15mm. You would need the 22mm one.
The drain plug depends on where it is going to be fitted. Never heard of needing one for a mains pipe.

[RockyBalboa]

The stop cock I posted is a 25 x 15 so the larger end would be for the MDPE and the other end for standard 15mm plastic pipe?

The water company want somethig basically like this:

[jagnet]

Both will be fine. Don't forget the pipe insert.

[stevensdrs]

You can fit that arrangement if that is what the water company specify but surely it would be better to fit 22mm size to get better water flow in the building.

[RockyBalboa]

Looking on the JG Speedfit website it states:

Connection to Mains Supply

In modern properties, water enters a building usually in a blue MDPE (medium density polyethylene) pipe. In order to comply with Water Regulation Schedule 2.10, the internal plumbing system should be connected via a Speedfit Stop Valve (Part Nos. 15STV and 22STV) in conjunction with a PE-Copper Coupler from the Speedfit range of Underground Fittings.

[jagnet]

If memory serves then 2.1 just says words to the effect of "don't contaminate the water supply". Either arrangement will suffice for that purpose.

That arrangement of fittings above is just J&G's solution using their products but the end result is exactly the same as using a plastic or brass stopcock straight onto the MDPE. I prefer the latter since it's only one joint before the stopcock rather than three, which is fewer potential leaks to deal with when the stopcock in the street refuses to turn off. It also reduces the risk of pipe bursts due to freezing before the stopcock as MDPE is more resistant than copper in that respect.

[RockyBalboa]

That makes sense!

So I'm thinking I need:

1. MDPE pipe
2. Stop Cock 25mm x 22mm
3. Piece of 22m pipe
4. 22 x 22 x 15mm reducing tee
5. Piece of 15mm pipe
6. Drain off valve on 15mm pipe

Does that sound okay?

[jagnet]

If the tee is for the drain off cock, then I'd just go with a 22x15x15 reducing tee and solder the drain off cock straight into that.

MDPE + pipe insert into 25x22 stop cock
Short length of 22mm pipe
22x15x15 reducing tee + drain off cock
15mm pipe into existing pipework

[dhutch]

RockyBalboa said:

That makes sense!

So I'm thinking I need:

1. MDPE pipe
2. Stop Cock 25mm x 22mm
3. Piece of 22m pipe
4. 22 x 22 x 15mm reducing tee
5. Piece of 15mm pipe
6. Drain off valve on 15mm pipe

Does that sound okay?

Sounds like basically that. I can take a photo of what we had if its of use, but yesm that.

Obviously there is not much point doing all that in 22mm if the feed into the house in then 15mm, however we took 22mm upto the hot water cylinder, from which the whole house feeds its hot and cold, in order to minimise pressure drop when using more than one tap/shower.

You will have a new service cock in the road, provided by the waterboard, so you can always isolate and change it at a later date.

You will also need a 25mm mdpe stop-end for the other end, to prevent dirt entering before it is connected up. Water Board requirement.


Daniel

[RockyBalboa]

jagnet said:

If the tee is for the drain off cock, then I'd just go with a 22x15x15 reducing tee and solder the drain off cock straight into that.

MDPE + pipe insert into 25x22 stop cock
Short length of 22mm pipe
22x15x15 reducing tee + drain off cock
15mm pipe into existing pipework

I'm trying to avoid any soldering at this stage - will the drain off valve push fit on to 22mm pipe?

[Pheo]

They’re almost always 15mm but JG etc do ones which can be push fit - I presume they go straight into the push fit 22mm reducing tee.

[RockyBalboa]

Ah yes, my mistake, 22 x 22 x 15mm reducing tee and the drain off valve can go on a bit of 15mm pipe.

[Gingerbread Man]

Personally I'd use a standard brass stopcock. Can be reseated and a new washer put in if it plays up in future. Wouldn't personally trust that plastic one in years to come, especially if boxed in.
25mm main to reduce straight down to 15mm is odd but if it suits your flow rates, then go with it. The John guest drain off valves are typically a standard brass drain off but with an extend tail and therefore suitable to go into a push fit fitting.

[dhutch]

Gingerbread Man said:

Personally I'd use a standard brass stopcock.

This. And turn it off once a year on your cats birthday or something.

[RockyBalboa]

Any particular advantages of brass?

What's the difference between the Poly and DZR:

https://www.toolstation.com/poly-stopcock/p16758

https://www.toolstation.com/dzr-stopcock/p19828

Can I fit it straight to the 25mm MDPE pipe without further fittings?

[Gingerbread Man]

Yes. Can compress straight onto it.

[dhutch]

RockyBalboa said:

Any particular advantages of brass?

What's the difference between the Poly and DZR:

https://www.toolstation.com/poly-stopcock/p16758

https://www.toolstation.com/dzr-stopcock/p19828

Can I fit it straight to the 25mm MDPE pipe without further fittings?

The 'poly' is 25mm one end, 22mm the other end, to go onto the blue polythene pipe. The other valve is 22mm both ends. They are almost certainly both DZR which is the grade of brass, used to reduce dezincification.

The 25/22mm will go direct onto the blue MDPE pipe, but the the pipe will need a insert for the plastic pipe.


Daniel

[stevensdrs]

dhutch said:

RockyBalboa said:

Any particular advantages of brass?

What's the difference between the Poly and DZR:

https://www.toolstation.com/poly-stopcock/p16758

https://www.toolstation.com/dzr-stopcock/p19828

Can I fit it straight to the 25mm MDPE pipe without further fittings?

The 'poly' is 25mm one end, 22mm the other end, to go onto the blue polythene pipe. The other valve is 22mm both ends. They are almost certainly both DZR which is the grade of brass, used to reduce dezincification.

The 25/22mm will go direct onto the blue MDPE pipe, but the the pipe will need a insert for the plastic pipe.


Daniel

Use this instead, goes straight onto the 25mm pipe, don't forget to fit an insert. https://www.screwfix.com/p/poly-stop-cock-25mm-x-2...

[RockyBalboa]

Just deciding if I should use 15mm or 22mm plastic for all the runs?

The flat is all electric so will have an instant water heater under the sink and 2 electric showers.