Compression fittings.

[MarkFish]

Last week I fitted two compression fittings between taps and copper pipes (15mm & 22mm) and both are weeping a bit round the thread. I've already tightened them with spanners much harder than I really thought was wise (to the point where I'm wondering if that is the cause of the problem).

Do I:

a) Pinch them up a bit more.
b) Take apart and slip some PTFE tape over the existing olive.
c) Cut the pipe back a bit and start again with new olive.

 

[DeltaT2]

Mark, all compression fittings, Type A or B should have a smear of Boss White(generic name) on the olive. Disconnect them & refit.

 

[swbjackson]

Compression fittings shouldn't need any sealing paste but many with brass olives do. Boss white should not be used on hot or cold water supplies as it is not approved for use with wholesome water. There are plenty available that are approved though.

 

[vibrobullit407]

I would take apart, rap some ptfe round the olive and use fernox waterhawk on the fitting and reconnect. Should work a treat!

 

[Whitespirit66]

Wan't old imperial pipes was it? 1/2" and 3/4" instead of modern 15mm and 22mm.

Although, the 15mm compression should be OK on 1/2".

 

[xr4x4]

All compression fitting these days are crap and will leak if even slightly over tightened.

Most compression fittings that I undo that are old have some kinda goo on them.

 

[MarkFish]

Wan't old imperial pipes was it? 1/2" and 3/4" instead of modern 15mm and 22mm.

Although, the 15mm compression should be OK on 1/2".

Almost certainly imperial.

However the 3/4 (22mm) is pretty much fine, the 1/2 (15mm) is the leakier one.

Although ironically they're both dry now. Wonder if it's temperature related.

 

[Charnwood]

However the 3/4 (22mm) is pretty much fine

Are you advocating the use of a 22mm fitting with a 22mm olive on 3/4" pipe?

 

[Charnwood]

they know f.ck all about Plumbing, they're oily rag engineers, not Plumbers. Any metal to metal joint needs a joint paste.

So, they dont subject their fittings to all sorts of pressures, temperatures, stresses and strains?

You're only a plumber. They are metalurgists and engineers.

Only kidding. (To a certain extent.)

 

[MarkFish]

However the 3/4 (22mm) is pretty much fine

Are you advocating the use of a 22mm fitting with a 22mm olive on 3/4" pipe?

Nope. If I was adovcating that (or anything else) I would have said so. I'm saying I've got two pipes which are an unknown quantity which could well be imperial.

The bigger of the two which is either 22 or 3/4 seems fairly watertight. The 15 or 1/2 is seeping more.

Strangely neither seem to be seeping any more.

Anyway, it sounds like ptfe tape on the olive isn't really a crime against humanity, so I'll try that. I've also got some spare olives so might start from scratch.

 

[swbjackson]

Compression fittings shouldn't need any sealing paste but many with brass olives do. Boss white should not be used on hot or cold water supplies as it is not approved for use with wholesome water. There are plenty available that are approved though.

And what experience have you based your poor judgement on, you're a DaftyDIYer!! Also, I did say Boss White was a generic term. So back to the drawing board Harry Greene. My company has fitted millions of compression fittings, never had a leak & all with Boss White or the likes. Compression fittings need a jointing paste.

How about over 30 years in the trade and an active member of my local branch of the CIPHE. Boss White is not a generic term, Boss white is a proprietary sealing compound that is not approved for use on wholesome (what we used to call potable) water. If you're company has fitted millions of compression fittings and never had a leak then your company is either incredibly exceptional or you're a liar. I suspect the latter. I rarely have leaks on compression fittings, occasionally I need to tweak them a bit when they weep slightly because I don't over tighten them in the first place. A couple of years back center brand rad valves came with a very inferior olive that kinked as you tried to tighten them so nearly every one leaked.

As for any metal to metal joint needing a joint paste that is absolute nonsense. Have you ever come across a ground face union? What about those compression fittings that I fitted the shower valve with on Monday? The manufacturers instructions specifically forbid the use of jointing paste on these because it can get into the thermostatic cartridge.

 

[mickyg]

unfortunately dicky thinks everything that was done 30yrs ago is still the best thing to do today. If you use decent copper olives you dont need jointing paste. Its the rubbish quality brass composite olives we get now that are the problem, a bit of jet blue is my preferred route but its really not a big deal what you use as long as it dont leak and its approved for the situation, which as pointed out boss white is not for potable water, and its not a generic term, nonsense. You tell someone to buy bosswhite they will buy bosswhite duuuh !!

 

[MarkFish]

Just popped some ptfe tape on the olives.

The 15mm fitting fits snuggly on the pipe with no play at all.

The 22mm doesn't fit snuggly so I suspect may be imperial. It's been on there for a week so I don't feel the need to do anything about it immediately.

What next?

 

[vibrobullit407]

I would take apart, rap some ptfe round the olive and use fernox waterhawk on the fitting and reconnect. Should work a treat!

If you see a compression joint with PTFE tape, DON'T touch it, you know it's been fitted by some DaftyDIYer or course cowboy. Real Plumbers use Boss White(generic name)!!

Nothing wrong with placing ptfe round the olive (sorted many a leaking compression fitting for me) if needed and as has been mentioned boss white is not for potable water where as fernox waterhawk is. Maybe I should have said use a suitable jointing compound and not just mentioned the one I prefer!

 

[DeltaT2]

Sussex???!! The water pressure there is pizz poor, in fact you're on a hose pipe ban there son. Lucky if you've 1 Bar water main pressure?? The compression fittings could be hand tight & still not leak!! So take it from a Real Plumber, joint paste on every compression joint, even with your pizz poor Engerlander water pressure.

As for unions, again face to face metals need joint paste. Oh you can read all the manufacturers drivel you like. But Real Plumbers use Boss White or the likes.