Speedfit plumbing

[Bert Coules]

For a short plumbing run in my new kitchen I decided to try Speedfit which I'd not used before. The couplers and elbows seem very secure, with the tightened nut squeezing the connection, but I'm less sure about the isolating valves: they don't have the compression nuts and seem to rely solely on the tightness of the push fit.

Presumably they are OK though, so am I worrying unnecessarily? Many thanks.

[Andrew Gabriel]

The tightened nut on the Speedfit I'm familiar with doesn't do any clamping of the pipe - it just stops the grab-ring release collar being pressed in.

Important things about the couplers - the pipework entering must be true and square and not subject to any bending stress, so make sure the pipework is supported by pipe clips, and not being supported by the fitting.

The O-rings have a specified life of 25 years. That might influence where you use them. (In practice, I've had one fail at 12 years, but that might have been a different make of plastic pushfit.)

Note that you can also use regular compression fittings with plastic push-fit pipe, but you must use a pipe insert in the cut pipe end where the olive compresses onto the pipe. I suspect regular compression fittings will achieve longer life, but still give you the ease of using flexible pipe.

I generally avoid plastic pipe, but when I have used it, I use regular compression fittings. The one case I had which failed with a pushfit was where a shower mixing valve came with pushfit connections (and the pipe used is actually copper, not plastic).

[John Rumm]

The pipe retention is really done by the sharp metal retaining clip that bites into the pipe. Lots of brands of pushfit don't have the ends that can be manually tightened and still work reliably. The speedfit design lets you make the joint feel a bit tighter by reducing the readiness of the pipe to rotate in the fitting (the rotation does not make any difference to the sealing which is due to o rings). They are also handing in that you can undo them past the end stop, which lets you dismantle the fitting and take it off the pipe easily.

[Bert Coules]

Thanks to John and Andrew for putting me straight. I shall now fit the Speedfit isolation valves with fewer qualms.

[newshound]

But I *would* use pipe inserts. Some pipes have markers to ensure that you get the pipe fully inserted, that is fairly important especially if you are working in tight spaces where you may not have good control. I have occasionally used a permanent marker or little collar of PVC tape to make sure I get the full insertion (after having a couple pop out before I got the technique). Also worth lubricating the seals, ideally with silicone oil or spray although a smear of washing up liquid is OK if you don't have silicone. (Pledge spray polish should also work).

[Bert Coules]

Thanks for that. I have in fact used them on the work I've done so far, and was planning to fit them again for the isolation valves. It's mildly disconcerting that Speedfit make two different types of insert: standard and "Superseal" - so the standard one isn't as good as it could be, then?

I found that getting the pipes fully home is helped by the fact that there's an initial resistance (presumably the O ring) and then a final stop. So it's a two-stage process and if you don't hear and feel the two clunks then you know that the pipe isn't fully home.

I didn't know about lubricating the seals; I'll do that for the rest.

[newshound]

I think of them as "older" and "newer" but that only reflects what I've generally been supplied. I've not noticed any performance difference. Also, you can mix inserts and pipes from different manufacturers, although it's probably not recommended and some are tighter than others (lubricant really helps!)

[Bert Coules]

That's good to know; thanks.