Arfa Daily Inscribed thus:



"Arfa Daily" wrote in message
...
Bit of a long post, but stick with it ... :-)

So, today, I finally got the time to go to our burger joint to fit
the pressure reduction valve that I bought a couple of weeks back, to
stop the 6 bar pressure relief valve ahead of the unvented water
heater, from lifting off its seat all the time. For those who haven't
seen the valve in my earlier posts, here it is :

http://www.plumbworld.co.uk/safeguar...cing-343-21866

It has a 22 mm through bore, and comes complete with custom 22 to 15
mm reducing olives, as well as standard 22 mm olives, if you are
going to fit it direct to 22 mm pipe. So far, so good. Off goes the
water, on go the taps. All drained down, and three inches whipped out
of the 15 mm pipe where it's going, in no time. I then fitted the
compression nuts over the pipes, and then put the two sections of the
reducing olives over the pipe ends, after carefully studying the
supplied diagram to make sure that they were going in right. The
diagram is quite clear, and the assembly order is exactly as you
would expect. Basically, the 'inner' part of the olive comprises a
'straight' section about 5 mm long that fits into the body of the
valve. Behind this, there is a 'flare' at about 45 deg that matches a
correspondingly angled 'seat' in the valve body. Behind that is a
'conical' section of again about 45 deg, tapering down the opposite
way to a 15 mm hole to accommodate the 15 mm pipe. This is the piece
of the adaptor, that is going to grip down onto the 15 mm pipe. There
is then a completely separate piece that is a brass ring about 5 mm
deep, that has a corresponding conical seat inside its front face,
and a square rear face to go against the inside face of the
compression nut. Unfortunately, the online instruction sheet doesn't
show this, so I've had to try and describe it.

What should happen, is that as you pull up the compression nut, the
conical seat of the outer ring, presses on the conical taper of the
inner part of the adaptor, crushing it onto the 15 mm pipe. At the
same time, the 45 deg flare a little further in, should be pulling up
against the corresponding seat in the valve body, to form a seal.

Except it didn't. Both sides dripped like a good 'un. The low
pressure side was actually worse than the high. And from here on in,
the day just got worse. I had been careful not to pull the nuts up
more than about a quarter turn beyond where the adaptor had obviously
gripped the pipe, as I am fully aware that over-tightening a
compression fitting can distort it and prevent it sealing. So I
carefully pulled it up a bit tighter. Not a jot of difference. Water
off again. Disassembled. Inner part of adaptor seemed to be tightly
pinched onto the pipe. I carefully examined the flare and the seat in
the valve, but both looked ok and undamaged. However, as that was
about the only place that I could see that water could be getting
past, I put a good wodge of PTFE tape around the flare, and bolted
back up. And still it leaked ...

Thinking that perhaps I was wrong then about where the water was
getting out, I then nipped to B&Q and bought a couple of end-feed 22
to 15 mm reducers, that had nice long straight bits at the 22 mm end.
As a safety net, I also bought a pair of 15 mm straight couplers.
Glad I did ...

With the valve back off, I fitted the supplied 22 mm traditional
olives over the reducers, and inserted them into the valve body. Nice
fit, and the olive is butting up to the seat in the valve nicely. Out
with the cutter again, and a bit more pipe removed to accommodate the
new length of the valve with it's reducer 'tails' fitted, and to
allow the original reducing olives to be removed, as of course, these
are now firmly clamped to the pipe, never to come off ...

Valve back in place, compression nuts pinched up, olives appear to be
clamped firmly to the 22 mm sides of the new reducers. Other ends of
the reducers soldered to incoming and outgoing 15 mm pipes. Water
back on.

AND THE ******* LEAKED. BOTH EFFIN' SIDES !!!!!

No amount of additional tightening, PTFE'ing, swearing at it or
kicking of the cat that wandered past the back door, would improve
it. So, with time marching on towards opening, I gave up, and fitted
a piece of 15 mm pipe back into the gap, using those two couplers
that I had fortuitously purchased ...

As both (very different) ways that I've tried to mount this thing
have failed to work in the same way, and the fact that the low
pressure side is actually worse than the high, the only conclusion
that I can come to, is that the example that I have has been machined
badly at the olive seats, or else the product overall, is a piece of
****. During over 40 years of DIY plumbing, I think I've seen most
general problems of this type, and I don't ever remember one
defeating me before. I'm not an expert by any means, but compression
joints and adaptors, are hardly rocket science. I'm not sure what to
do now. I was thinking that I might be able to get an O ring in
between the olive and the seat, but I'm not sure that would be
successful. Anyone got any suggestions, or can think of anything that
I'm doing wrong, or missing. Incidentally, when it was in place, with
the pressure gauge fitted, it did at least seem to be working, with a
steady 3 bar output.

Arfa


Oooops ! Ignore this (except for amusement at my misfortune ... )
Accidentally posted to wrong group :-\

Arfa

Apart from a wry smile :-)
I would be interested in the cause and solution !

--
Best Regards:
Baron.