I need to run a hot water supply to a new wash basin and the only supply anywhere near is the 15mm pipe which takes the hot supply from the combi-boiler.

The problem is that the pipes are close together here and also appear very rigid so I’m concerned that I would have to cut through the pipe with a hacksaw blade (no room for a pipe-slice) and once done there may well be insufficient movement in the pipe to enable me to fit a Tee piece.

I have seen these “Self-Cutting Isolating Valves” but do they affect the flow in the existing pipe which supplies the rest of the house.

I assume they cut a small hole in the pipe but as the new connection is only to a wash basin I would assume the flow would be adequate.

Any comments / suggestions?

John

I wouldn't go down that route personally. Are you sure there is nowhere on that pipe you can safely cut in and fit a proper T joint?

Commonly used for fitting washing machines and garden taps they work fine but they can sometimes leave a loose shard of metal in the pipe you are cutting into, this caused me a problem a few years back when the shard flying about inside the pipe caused a pin hole in in the rubber liner of a braided flexible tap connector.

[Edited on 3/3/13 by britishtrident]

I have used them, and never had an issue. good point about the shard of metal,though.

MikeF

I have fitted dozens of them, the only problem I have encountered is the metal spigot that pierces the pipe rusting, and blocking the flow. After many years I might add.

Wouldnt dream of using one myself. You can get slip couplings, basically a straight connector that has no ridge in the middle so it can slide fully onto the pipe. This means you dont need to be able to push the pipes apart, just move them 15mm to one side. Fit your tee and then use the slip coupling to rejoin it all. Then its all soldered.

Easiest to use 15mm plastic pipe. It's all pushfit,just don't forget to use inserts on the plastic pipe connections. Screwfix sell it quite cheaply.

If you can cut through with a hacksaw, you can fit one of these, it's not cheap but you might find it cheaper elsewhere, it works by having a 'sliding' part which will extend it to reach, therefore no need to move the pipes.

Screwfix LINK

The self-cutting valve is still an attractive option because it wouild be easy to fit but I think I may go with the slip coupling suggestion if I can get to it OK. (Somehow it just seems like a better engineering solution).

I quite like the idea of the Speedfit Slip Tee but not sure it would be OK with a hacksawed tube end. I always thought you needed to use a tube cutter so it would slide through the internal O Ring without damage.