Help... Compression joint... Tiny bit leaky...

Hi,

Well, I have the cold water distribution in place in my under stairs cupboard:

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Well I've capped off (or closed valves) and pressurised the dry pipe to

2.5bar. Been over it with gas leak spray and several joints were leaking (I'd only done most up half-turn - marked the fitting with a Sharpie).

Tweaked most of the leaky joints up a bit and got a perfect seal.

However, I have 2 joints that are better but not perfect:

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Before they were chucking a big bubble (3mm) every second or two

Now they are popping a tiny bubble about every 10 seconds as seen in the picture.

The 22mm joint is done to about 3/4 turn and has gone "tight". I am very loath to turn it more.

The 15mm I forgot to mark, so not sure how much of a turn. I could go more, but I've tweaked it up quite a bit. Bit scared now...

It's not common to dry test a system like this, but as I'm swapping the main water over to the other end tomorrow I wanted to debug this now.

Anyone care to venture an opinion if I should dare tweak these joints more - or just test with actual water and see if any weeps self heal. Or even be prepared to put some compound on the joint (what?)

Anyway for the morbidly curious, this is what the layout will do:

Basically, mains will come in from the top right, through the pressure reducing valve (we have 7.5 bar here).

Right to left:

(Top) Pressure test point - will get gauge on top (Top) garden tap take off

(mid 22mm lever valve) - secondary house isolation. This will shut the house down but leave a feed to the garden taps for watering devices.

Next 3 - kitchen, bathroom, shower room cold takeoffs.

Next with butterfly valve - electric water heater will move to here;

Next top - toilet/washing machine;

Left 22mm - cold to boiler.

Reply to
Tim Watts
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If it's leaking find a bigger spanner, a little bit of 'squawking' never hurt any compression joint I've done ...

Reply to
Andy Burns

Hi Andy,

Got no "squeak" right now as the threads are full of gas spray which turns out to be a pretty good lubricant :)

It did move it and it was medium tight but at the point I just go to, the resistance to turning jumped markedly which makes me concerned that I've reached a critical point???

Reply to
Tim Watts

If you undo the joint is the olive loose, tight, or cold welded(!) onto the pipe?

Reply to
Andy Burns

OK - I'll go and see...

NB to self - depressurise pipe first!!!

Reply to
Tim Watts

Hi Andy.

Here:

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Despite *extreme* care[1] to get everything planar, perpendicular and level, that particular pipe and a couple of others ended up slightly no in line by the time I'd mounted it on the wall, and soldered the incomer on.

The vertical 22mm is about 1-2 degrees off true.

Anyway, as far as I can tell the olive is tight on the pipe and not obviously destroyed - though there is a slight "bit" on the right side where it's been nipped between the nut and the pipe due to the slight skew I guess.

Anyway - whether undoing and doing up (I pushed the pipe back inline as I did it up) or the fact the whole joint is now full of soapy liquid - it *seems* to have stopped bleeding air bubbles at 2.5 bar.

This particular joint is a *must be right* joint - no possibility to cut and redo.

I should undo and redo the other 15mm one near it - perhaps that will get better :)

Thank you so much - I think that has helped!

[1] I made this assembly up on a bit of scrap ply on a table in the shed, mounting the clips with a ruler and set square using long tails off the tees as soldering with valves in places would have damaged the valve seals.

I then mounted the assembly on one row of clips and marked the positions for the rest, demounted, added clips and put back (and took off and had to adjust a few clips).

I'd finished with a "low strain" mount (ie no clips were forcing any pipes) - but despite that, the action of doing up big valves seems to make things move a bit and knock one or two things out of alighnment.

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Over the top of this I will have to make up a hot distribution bar. This will be a bit simpler - only 5 takeoffs plus a boiler in.

Rather than prat about with crossovers, I've decided to just mount it on

50x50 batten to lift it into a different plane than the cold - the pipes should cross without effort and interleave - the kitchen hot next to the kitchen cold, etc.

But no urgency for that - just need the cold done for now...

Reply to
Tim Watts

Done that - seems better. I cannot detect any leakage.

Woohoo...

So tomorrow is make up a horizontal with a couple of elbows to take the main valve to my new pipe in the kitchen.

It should be a straighforward operation, but as usually I expect the "Fuck Up Fairy" will come to visit...

But as least I can get mashed and watched TV now, safe in the knowledge that I think the current stuff is more or less debugged.

Christ knows how they did this shit with iron pipes! Or lead - which whilst easy to bend (but by-eck, it must have been a stuggle feeding it around a house weight wise) the joints were a work of art taking an hour or more per joint.

Then again, they didn't have such complicated houses with 2 bathrooms, heaters and boilers and stuff...

Reply to
Tim Watts

Whenever possible, I first tighten compression joints with the fitting held in a vice, and then take them apart, check that the olives are tightly crimped onto the pipes, and smear some LS-X round the olives before re-assembling and re-tightening in the required location. I rarely have any leaks that way.

Reply to
Roger Mills

That's a good thing about compression fittings, they're less "final" than solder, but I still dislike them for general tees/elbows/couplings, too bulky.

From what I've seen of making wiped lead joints, quite a skill ...

Reply to
Andy Burns

I was going to use a compression elbow to make the final connection to the mains - because I want to make sure the link pipe can come away enough to allow the main valve to be replaced if required.

But, when I did a "remind myself how tight to do compression joints" in the shed with some scrap, I just could not hold an elbow without it either slipping out of the adjustable spanner, or on one go, actually punch a hole in the side!

I have amended my plans to use a straight compression fitting.

How do you hold an elbow whilst tightening????

I watched my dad do one to repair a burst pipe in the garage (all lead).

It took him about 2 hours. He had the tools - dolly, tallow, moleskin. It was perfect when he'd finished. But labour intensive!

Reply to
Tim Watts

I used to take them apart - now I rely on "half turn by marks" then whatever it takes after that.

Did some pre- assembly experimentation today on some scrap.

Half a turn, at least on 15mm *just* starts the olive biting into the pipe - for brass olives anyway. If you look down the pipe inside with a strong light, you can just see a couple of rings where the edges of the olive are biting.

22mm seems mostly similar.

I did a copper olive on one attempt and it refused to bite the pipe (no visible rings) - so I feel happier with my personal decision to always use brass. I expect they work, but to my mind, if the olive becomes slightly smaller than the normal OD of the pipe, there's no way it can actually every come apart.

Reply to
Tim Watts

Feels about right, if you create a 'neck' inside the pipe that's overdone really, when ripping out old pipework I've seen a few like that which hadn't actually caused any problems, but getting the valves off was a job for a hacksaw rather than an olive puller ...

Reply to
Andy Burns

Any leaks I've had over the years have been down to that. It's the Hamlet cigar moment

Reply to
stuart noble

Some have flats on the side of the elbow bit that you can get a spanner on, although they also tend to be on the fairly thin walled bit of the fitting and hence its not difficult to fold the side in an puncture one. I usually find that water pump style pliers can be aligned with the front of the jaws toward the back of the nut you are not tightening, and the elbow tucked into the throat of the jaws close to the fulcrum. The tips grip the nut, and the throat can be wedged against the side of the elbow to restrict the rotation.

Yup it feels like cheating these days with ledlok (and similar) transitions fittings ;-)

Reply to
John Rumm

I would use either water pump pliers or mole grips clamped onto the fitting.

Though actually, I'd be more likely to use a pushfit fitting :-)

Reply to
Chris French

Sound like I was wise to go soldered in the end:

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Anyway, after a heart-attack inducting day, it is done. No serious leaks. Obviously the soldered joints are all OK.

The top of the main c*ck in those pictures was a bit irritating - but I've got it up to 3/4 turn and really tight and I think the last tiny weep has stopped (2 "raindrops" in about 30 minutes).

OK - probably about 1/2 "raindrop" in the last 15 mins.

Shall I leave it? Ponders... Don't want to get too violent as I might disturb the bottom fitting which is dry and 6 years old...

Anyway - no serious leaks around the back on the main distribution bar either. And they are easier to access (main valve is going to be behind a cupboard with access for operating).

I did flush every blanked connection into a bucked until it ran clear - took a *lot* of buckets, but didn't want any flux hiding in short dead ends...

WTF is in Fernox flux anyway - it made the water milky white and frothy?

Reply to
Tim Watts

Undo the nut and wrap a bit of PTFE tape round the olive.

Reply to
harryagain

Well, I was going to give it one tiny tweak, but short of longer spanners, it is to tight to move in a controllable manner.

Tiny tiny weep...

:-<

Reply to
Tim Watts

Not fitting a drain-c*ck shortly after the main inlet valve?

Reply to
Andy Burns

No harm, its not like a pipe cutter is much slower to use than a spanner should the need to dismount arise.

I would give it another 1/16th to 1/8th turn. (are we talking water raindrop, or raindrop sized bubble with a gas test?)

I use Powerflow, but that does much the same.

Reply to
John Rumm

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