plumbing question..

[G20RG B]

Hi guys,

Trying a bit of plumbing DIY and could do with some help.

I have moved a cold water pipe that was going up to the attic see the flexi pipe in the pictures below. I would like to run a hot water pipe up there also( see the copper pipe below with the stop end).
If I turn of the cold water supply ( I have a combi boiler) and run the hot tap to drain the pipe will it be ok to take the stop end of the copper pipe without flooding the house?.
And should I reduce the pipe from 22mm to 15mm and then run the pipe up to the attic?

Any advice welcome.

[m4ckg]

you won't flood the house if you drain it down like you explained, your probably best keeping pipe in 22mm and then reducing to 15mm in the loft.
if you intend on using push fit onto the copper use a pipeslice cutter to make a smooth cut on the copper pipe.

[Ferg]

Run it in 15mm if it's from a Combination Boiler. Not a lot of point in running 22mm.

[G20RG B]

Guys,
Thanks for your replies,

I have completed the small plumbing job today using a 22mm to 15mm elbow then copper pipe to the wall then push fits up to the attic. I put isolating valves on the flexi pipes hot/cold that go up to the attic so when I get around to connecting them to sink/toilet i will not have to shut the mains water of.

Thanks again guys