On Jan 28, 9:37*am, "Arfa Daily" wrote:
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

FWIW, I usually buy a threaded body PRV which geneally has a union nut
on one end to allow the PRV to be easily removed from the line for
serviceing. I can then use solder to thread adaptors to connect to the
piping if metal or PEX compression to thread adaptors for plastic
piping..
Take your PRV and put a valve on the output side pipe and a hose bib
fitting on the input pipe and connect it to a hose bib [or whatever
you call the tap you connect a garden hose to over there] and that
allows you to test it for leakage.
I agree, though, that I have seen far too many flare and compression
fittings that were so badly machined that they would never seal up. I
also had a gas valve in my house when I bought it [10 yeas old] that
the body was porous and the gas leaked right through. It was a very
cheezy valve made in Ch**a. To be on the safe side I replaced all the
fitings from the feed line to the controller valve to be sure of
fixing the leak, using best quality parts, naturally.

Neil S.