Stop very slow leak...

[DrDan]

Morning!

I've got 2 tiny leaks in my new pipework at the points arrowed.

View media item 94596
Top left - New compression fitting on 4 inch bit of 22mm pipe to a flexi hose. Used 5/6 wraps of PTFE on top of olive. No drips on the floor overnight but I can see a bead of water under the nut.

Bottom right - This is a very old nut onto a new brass tee. Original olive with same PTFE as above. No drips again and not even a bead of water, but I can just make out a ring of moisture under the nut.

I really don't want to recut any pipework and the nuts are nipped up as much as I can (maybe a bit too much).

- Can I dismantle the joints and use a jointing compound like LS-X to fix?
- Should I redo all of them with LS-X for a belt and braces approach?

Any advice welcomed, apart from "redo the lot with solder", it is what it is!


Cheers...Dan

 

[DP]

Rip out, throw those silly ISO valves in the bin (they will leak sometime in the future). Use copper instead of flexy pipes. No ptfe or jointing compound needed if quality olives and fittings used

 

[Tipper]

It may be your use of PTFE tape.

In my book PTFE thread tape is simply that...tape you wind into a thread to seal it in another thread as a replacement for hemp fibre and paste. It was never designed for wrapping around olives in compression fittings and can be cut through by the mating parts allowing leakage. Even on threads it sometimes gets stripped out by the tightning of the threads.

I suggest remaking the joints with a suitable joint paste such as Boss White or indeed LS-X (which I think is silicon based) or similar. If it's on potable water then an appropriate grade of paste should be used that won't contaminate the water. Oh and remove the PTFE tape.

 

[Agile]

I suspect that the joints may be damaged hence the leaks.

LSX is mainly used by bodgers, including plumbers after a quick fix.

However I would always want to do the job properly and all joints can be remade and sealed using just PTFE tape where appropriate, and that can include around damaged olives too. I also sometimes use silicone grease to lubricate threads to create more pressure with less torque.

The only place that I would half agree that LSX has a place is to do a quick repair on waste pipes which are damaged or wrongly fitted.

The rule is that LSX cannot withstand pressure so its unsuitable for any pipes with pressure on them.

Tony

 

[DrDan]

So..stage one of fix. I bought some LS-X, took apart and inspected the leaky joints. I removed all the PTFE tape from both joints.

- The bottom right brass olive was covered in places with a brown hard rust like substance so I gently used some wire wool to remove it until shiny again. Applied some LS-X, tightened, left overnight with water off. This morning I turned the water back on and after an hour there's the same ring of moisture once again!

- Top left - it's a new brass olive but now in a different compression fitting (22-15mm reducer, getting rid of the flexi as suggested). Same treatment as before, LSX, left overnight. Same tiny bead of water.

Shame that bloody work gets in the way, I only get from 7pm-10pm to fiddle!

From the advice you chaps have given me, I either should or shouldn't use PTFE, LS-X or indeed anything at all!

I think I might cut the brass olives off both the joints and start again. Do you have to cut the pipe back once the olive is off or can you use the same bit of pipe if it's unscratched?

Tempted to go Speedfit here.

Cheers..Dan

 

[Madrab]

If you are getting leaks from compression fittings that resists any attempt to seal then it's time to replace the fittings IMO.

Mating faces/olives become worn or distorted over time that PTFE can sometimes overcome but if after numerous attempts it still fails then time to replace. Also ensure that the pipe ends haven't been damaged/overtightened (necked) where the olives are as the compression fittings will never seal properly.

or get someone that knows how to soldered to do a proper job.

 

[longdogs]

Sometimes a old nut & olive onto a new fitting doesn't work because the old fitting was slightly different, meaning that the old olive does not sit snug against the fitting.

 

[Whitespirit66]

Bin the brass olives and use copper ones. They're softer and will invariably provide a much more reliable seal.

 

[Agile]

Yes, I was think that.

A soft copper olive will often reclaim an old joint and squashed pipe.

Funny how we all advised making the joints with PTFE tape and off he goes with this LSX again!

Tony

 

[DrDan]

Funny how we all advised making the joints with PTFE tape and off he goes with this LSX again!

I know, I know!! To be fair Tipper did say to try LS-X and bin the PTFE, I used PTFE originally but that didn't seal either.

*hangs head in shame*

Anyway I'm redoing the leaking joints with new olives and PTFE tomorrow. BUT I looked for some 22mm and 15mm copper olives but couldn't find any in Plumbcenter, Wickes, Screwfix or Toolstation..all brass! The world of plumbing is against me it seems.

 

[Whitespirit66]

Plumbase do them in copper.

http://www.plumbase.co.uk/westco-copper-olives-15mm-6186-2228675

Or, if you're not in a hurry, there's Ebay.

http://www.ebay.co.uk/itm/15mm-Copp...657?pt=LH_DefaultDomain_3&hash=item1c51374fa9

If I fit something that comes supplied with brass olives, I always use copper ones instead. Large bags of copper olives are cheap on Ebay.

 

[longdogs]

Plumbase do them in copper.

http://www.plumbase.co.uk/westco-copper-olives-15mm-6186-2228675

Or, if you're not in a hurry, there's Ebay.

http://www.ebay.co.uk/itm/15mm-Copp...657?pt=LH_DefaultDomain_3&hash=item1c51374fa9

If I fit something that comes supplied with brass olives, I always use copper ones instead. Large bags of copper olives are cheap on Ebay.

Me too. Strange how we all come to the same conclusions. I only ever use the brass ones on chrome pipe or when I run out of copper ones.

 

[Madrab]

Yup, I'll agree to that too, copper being softer doesn't need as tight a turn to seal rather than the harder brass.

Will chose copper over brass every time.

 

[DrDan]

Thanks for the Plumbase link, not heard of them. Turns out there's one 5 mins away, result!