taper iron pipes to capture nut connectors

[Gyn_Paul]

I'm installing a central heating storage tank which has 1-1/4" iron flow and returns. These are connected by similar sized flexibles which terminate with female capture nuts. These would traditionally mate to whatever with a fibre washer to make them watertight, however the iron pipe is essentially a taper fit, rather than a union, and 2 out of the 4 of them are weeping slightly regardless of tightness, and I suspect the end of the pipe is actually cutting into the fibre washer. I can't see that adding hemp/boss white to the thread would help as the thread itself isn't where the leak is occuring.

Anyone got an elegant solution for this? (I'm stuck with the flexys because the tapings on the tank are all at peculiar angles)

p

[Chancer]

Have you filed up the ends of the fittings flat and square?

Normally the fibre washer will seal after that.

[Théière]

Don't use a fibre washer, use a crushable copper washer or an annealed copper washer or a Dowty seal.

[Gyn_Paul]

[quote user="Chancer"]

Have you filed up the ends of the fittings flat and square?

Normally the fibre washer will seal after that.

[/quote]

No, but I ran the palm of my hand across it, there were no burrs. Bit late to think about filing - it's got 3000 L in the tank now.

I'll drain it in the summer and tackle it then. I did think about putting the side of a grinder on it, but worried about getting a perfectly flat surface which wasn't then at 90 degrees to the pipe.

[Théière]

[quote user="Gyn_Paul"][quote user="Chancer"]

Have you filed up the ends of the fittings flat and square?

Normally the fibre washer will seal after that.

[/quote]

No, but I ran the palm of my hand across it, there were no burrs. Bit late to think about filing - it's got 3000 L in the tank now.
I'll drain it in the summer and tackle it then. I did think about putting the side of a grinder on it, but worried about getting a perfectly flat surface which wasn't then at 90 degrees to the pipe.
[/quote]

Well you only posted it yesterday! As Chancer tried to explain smooth but out of square won't seal.

 

[BIG MAC]

A taper into a parallel is not a great idea if that's what you are faced with. I would go taper / taper bushing with a parallel male end to make off into your fitting and seated correctly. Boss white and hemp in the tapers and copper / fibre , dowty in the fitting as per other correspondents

[Chancer]

I get your point but usually a taper thread is used into a parallel one for sealing, in fact I dont think that you can get female tapered BSP threads.

However your suggestion is good as the tapered fitting will almost certainly not have a machined end as its designed to go into a male parrallel thread with bosswhite/hemp, even if the flexible did seal the nut may work loose.

the biggest problem I have had is with the eccentric BSP male/male bosses used to ratrapper the hole centres of shower mixers, you can never fully tighten them to their final position and any leaks are concealed within the plaster or placo behind the tiling before it becomes a catastrophy.

Using a Loctite pipe sealant clone has transformed my plumbing from sieve like to just leaky.

[Dave&Olive]

Hi Ok

          You need to go into brass to get your idea to work. best would be to fit barrels and then male brass connections you can then fit what fittings you want to

                       Dave

[BIG MAC]

I read this all wrong - you have an inch and a quarter steel pipe - going to flexi? why not simply introduce a threaded valve on the steel pipe and you can specify what you want on the other side whether you want a mating face / thread or captive nut?

With the pipe size you have I am thinking hotch potches of fittings aren't going to look tidy and likely to be expensive - I would get down to your desired size quick as I can and 11/4 is a hefty make up. Also if this is a flow and expansion tank (don't think permitted in France) I wouldnt want flexis which may soften and kink if the water gets very hot.

Also out of curiosity if this is a header tank...how are you filling it? is it via a ball valve?

[powerdesal]

''Also if this is a flow and expansion tank (don't think permitted in France) ''

How do plumbers in France pipe up a solid fuel fired CH cooker / boiler ? ie Rayburn / Stanley / Wamsler etc.

[Gyn_Paul]

Hi Mac,

3000 litres for an expansion tank? Even I would think this is a bit of an overkill !

This is a Akvatherm thermal store which stands 2.5m high and has 4 x 1-1/4 tapings, 2 high, and 2 low, connected internally to feed pipes running diagonally up and down to the highest and lowest points in the tank. The idea is you connect one ( H + L) pair to the boiler, and the other to the CH, the hope being that you can heat the contents, and subsequently draw off the heat with the minimum of internal turbulence. Maintaining so-called 'layering': the principal being that 2 foot of water @ 60 degrees C is more use in heating a house than 8 ft of water @ 30C.   

Probably because of the way the pipes are arranged internally, the tapings are not aligned vertically, nor are the pairs 180 degrees round from each other, not yet 90, but a sort of 105 for the top ones, and 85 for the bottom ones. Hence the need for the flexis, as only one pipe could ever be at 90 degrees to the pipe runs (in fact the top CH flow goes into a 3-way mixer, then to an elbow, and the other 3 have flexis). The curves are quite gentle, and I shall monitor them for collapse (believe me, a 1-1/4 flexi is quite butch!).

It's filled from the mains, and has a 3-bar pressure relief valve on the top - oh, and there's a 300 l expansion pressure vessel connected to the boiler return.

Now if I could only get the damned controller to recognise the 3-way valve has a travel of 90 degrees I'd be laughing!

p

[BIG MAC]

If someone had said a stratification calorifier...would have been easier to visualise :-)

[Gyn_Paul]

[quote user="BIG MAC"]If someone had said a stratification calorifier...would have been easier to visualise :-)[/quote]

Listen, I have quite enough trouble, at my age, remembering (let alone spelling) the words I used without summonsing up even bigger ones!

Besides which the calorifiers I knew in the building I worked in were only about the size of a very big DHW cylinder.

p

[BIG MAC]

[quote user="powerdesal"]''Also if this is a flow and expansion tank (don't think permitted in France) '' How do plumbers in France pipe up a solid fuel fired CH cooker / boiler ? ie Rayburn / Stanley / Wamsler etc.[/quote]

Make up unit - index rad without TRVs - ballon and expansion vessels would be my guess

[BIG MAC]

[quote user="Gyn_Paul"][quote user="BIG MAC"]If someone had said a stratification calorifier...would have been easier to visualise :-)[/quote]

Listen, I have quite enough trouble, at my age, remembering (let alone spelling) the words I used without summonsing up even bigger ones!

Besides which the calorifiers I knew in the building I worked in were only about the size of a very big DHW cylinder.

p
[/quote]

 

Ummm the Domestic hot water cylinder is a calorifier....just not a vey big one and generally without strat pumps etc....although mains pressure domestic calorifiers are now coming with de- stratification devices and there are some retro fit ones too.