On 29/01/2012 02:14, Arfa Daily wrote:


"Dave Liquorice" wrote in message
ll.co.uk...
On Sat, 28 Jan 2012 18:52:56 +0000, Roger Mills wrote:

22mm fittings can often seem as if they are fully tight when they're
not, because of the friction in the threads.

I support that idea, 22mm can be quite stiff unlubricated. I find
that unlubricated finger tight, then half a turn with a spanner is a
good starting point, if it "squeals" then it's probably sealed. Even
so another quarter to half turn still might be required.

I do tend to put a smear of boss green over the olive and in the
threads not as a sealent just as a lubricant.

Arfa is one of the more experienced DIYers in here, as indicated by
the things he has tried and precautionary purchase of 15mm couplers.
This does point to something up with the valve itself, are the 22mm
olive brass or soft copper? Perhaps copper ones would make it seal?

--
Cheers
Dave.



Thanks Dave, and also to Roger for his suggestions. All appreciated. The
first-tried 22 mm to 15 mm adaptor olives, are, I think, brass. I have
to say that when I first looked at them, and decided that they were
brass, I thought "Hmmmmm", figuring that they were going to take a lot
of pulling down to get a good 'bite' on the pipe. The traditional olives
that I tried for the second method of getting a fix, seemed to be soft
copper, which is why I was particularly vexed when I didn't get a seal
right off.

Looking back on it now I've had a chance to calm down, you could both
well be right, and I have been too cautious in the tightening, mistaking
the compression nuts tightening up from friction, for them being fully
tight because they had done their job. Most of my experience with
compression fittings, has for sure been on 15 mm, so I've maybe made
myself a victim of my own inexperience with 22 mm, added to a natural
caution of over-tightening.

22mm can be difficult to get tight enough in some cases... a bit depends
on the ease access and the size of the spanners etc[1].

I usually stick a few turns of PTFE on the threads to act as a
lubricant, and stop it squeaking when tightened. It tends to make it
easier to get the water tight joint with less physical force since more
of the torque gets to actually rotating the joint rather than overcoming
the friction.

[1] I remember having great difficulty tightening the nuts on the ends
of some butterfly service valves in a CH pipe above a kitchen cabinet.
There was probably only 6" of height between cabinet and ceiling, and
that meant that longer spanners could not rotate enough to get the next
flat into position, and short ones could not get enough torque in there
easily!

Might be a day or two before I can try anything. My elder daughter has
had to go to hospital tonight, and they've kept her in, so I don't know

Sorry to hear that. Hope she's well soon!

quite what time I'm going to have Sunday to 'play', and I am pretty busy
next week with the 'day job'. I'll let you know how it goes. Thanks
again for the advice lads.

Let us know how it works out...

--
Cheers,

John.

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