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.

In article ,
"Bert Coules" writes:
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.

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).

--
Andrew Gabriel
[email address is not usable -- followup in the newsgroup]

On 28/01/2017 10:42, Bert Coules wrote:
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.

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.


--
Cheers,

John.

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

On 1/28/2017 5:23 PM, Bert Coules wrote:
Thanks to John and Andrew for putting me straight. I shall now fit the
Speedfit isolation valves with fewer qualms.



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).

"newshound" wrote:

But I *would* use pipe inserts.

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.

On 1/28/2017 6:52 PM, Bert Coules wrote:
"newshound" wrote:

But I *would* use pipe inserts.

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 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!)


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" wrote:

I think of them as "older" and "newer"...
I've not noticed any performance difference.

That's good to know; thanks.