Plumbing advise needed

[Vagrant No2]

Had the hot water cylinder bust a seal on Thurday night so had a nice water fall down the kitchen wall and lounge ceiling . Thanks to Nigel's (Koi) technical help I changed the cylinder yesterday . But I got a leak from one of the coil joints on the cylinder where the pipe joins the cylinder coil . I dont want to tighten any more in case I twist the fitting in the tank and this one pops . I have tried PTFE tape and 'Boss White' on the joint when assembling but wont stop leaking . I dont want to keep draining the system as takes so long to fill and re bleed . Does anyone know of a product I can use on the outside of the joint to seal it and not do any thing that would stop me from undoing the joint in the future ?

[Sancho]

Is there some kind of washer in the joint? I spent ages dicking around with joints on my bath taps and it was all down to the wrong sort of washers.

[RodLeach]

Bit of a bodge but silicone would probably do.

[BUSHWHACKER]

Yeah, as Sancho said. Try changing the normal compression fitting on the end of the pipe you're connecting to the coil, with a straight tap connector with a fibre washer.

[fatfires]

Yeah, as Sancho said. Try changing the normal compression fitting on the end of the pipe you're connecting to the coil, with a straight tap connector with a fibre washer.

as above ok if 3/4", if 1" bsp would sugest sticking with PTFE but with a smear of boss white or silicone before making the joint, I find most folks that have weeps on BSP threads dont use enough PTFE or wind it on the thread the wrong way, If you are looking into the fitting, tape goes clockwise and from the start of the thread towards the cylinder, can be a bugga if it is a prelagged cylinder, but if you have a problem, carefully cut a donut of the insulation away - dont score the cylinder! and stick it back once the joint is sound.
carefully check tighten the locknut on the coil spiggot they have been known to come loose and weep and your joint could have been OK all the time!
if you are useing normal thin PTFE you will probably need 15+ turns

[SHIREHORSE]

Are you positive it is from the joint you have made, it may be that you allready have over tightened it and twisted the coil nut. If it is only leaking a very slight weep you could try heating every thing up leaving a rag underneath, there is a good chance it will seal itself.

[fatfires]

have you sorted it?

[Albannach]

if you are useing normal thin PTFE you will probably need 15+ turns

Where did you hear that?

Plumbing is my family business and I've never ever seen one of our plumbers putting 15 turns of PTFE on a joint. 3 or 4 yes, 5 as an exception. My grandfather would have sacked them on the spot if they dared put more on.

Vagrant, what type of joint is it? Stag jointing paste will fix almost anything, but shouldn't be needed on a new joint.

[fatfires]

Where did you hear that?

Plumbing is my family business and I've never ever seen one of our plumbers putting 15 turns of PTFE on a joint. 3 or 4 yes, 5 as an exception. My grandfather would have sacked them on the spot if they dared put more on.

Vagrant, what type of joint is it? Stag jointing paste will fix almost anything, but shouldn't be needed on a new joint.

With all due respect, I have only been in the trade in excess of 40 years so probably know nought, what I do know is that, a) cylinder threads are not the best cut threads around. b) PTFE is a self shreding tape, what is not needed will be shreaded out of the joint and as a reel costs pennies better to be safe than sorry. c) in grand fathers day it was probably hemp and boss white and if he was so tight and petty minded I for one am glad I never knew or worked for him. (would I love to have been a fly on the wall at the employment tribuneral...'I put too much tape on a joint and he fired me!I wasted 3p!) d) bear in mind sugestions are made with the best of intentions - concidering you have a familly business I am suprised you didnt offer your wealth of knowledge earlier, I would have thought an experianced familly business member would at least have known what joints are on a standard cylinder!
You are right stag shouldnt be needed on a new joint...unless it is BSP threaded steel pipework, stag on its own on a hot copper/brass joint will just harden and be verry difficult in the future to remove if needed.
as a side, if your plumbers use 3,4 or 5 turns on 15 mm you must get a lot of call backs for leaking rad valve tails unless you are using the new thick type tape...oh silly me I did quantify that as well earlier.

[Vagrant No2]

Thanks for the replies . I did go and buy some 'leak fixer and jointing sealer ' made by Fernox . It said can be applied to outside of joint to prevent draining down . Well it is sh1t and dont work . So I redrained the system and removed the joint and did apply the Fernox stuff and a fibre washer to the joint and refitted . Then spent the next 1 1/2 hrs rebleeding the system again . So far so good but looks like the problem has moved to the other joint on the cylinder coil but just a drip every 1/2 hr or so . Going to leave it and see if it 'furs up' and seals it self like some do.
Got a line of smelly kids and adults now waiting to use the shower .No one been in since Thursday or a day or 2 before !!

[fatfires]

Thanks for the replies . I did go and buy some 'leak fixer and jointing sealer ' made by Fernox . It said can be applied to outside of joint to prevent draining down . Well it is sh1t and dont work . So I redrained the system and removed the joint and did apply the Fernox stuff and a fibre washer to the joint and refitted . Then spent the next 1 1/2 hrs rebleeding the system again . So far so good but looks like the problem has moved to the other joint on the cylinder coil but just a drip every 1/2 hr or so . Going to leave it and see if it 'furs up' and seals it self like some do.
Got a line of smelly kids and adults now waiting to use the shower .No one been in since Thursday or a day or 2 before !!

Wouldnt reccomend leaving it, it could lead to corrosion, I know it is a pain but treat it like the other one - better safe than sorry!

[Vagrant No2]

I will be checking it everyday . I do need to partial redrain to add the inhibitor stuff any way so may do next weekend .

Thing is I needed to change my clicking starter this weekend as nearly got stuck at a petrol station this week as it just would not turn over . Hope I got enough diesel to last till next weekend !!
Had the spare starter in the back of Surf for 3 months and never got to fit it yet.

[Albannach]

With all due respect, I have only been in the trade in excess of 40 years so probably know nought, what I do know is that, a) cylinder threads are not the best cut threads around. b) PTFE is a self shreding tape, what is not needed will be shreaded out of the joint and as a reel costs pennies better to be safe than sorry. c) in grand fathers day it was probably hemp and boss white and if he was so tight and petty minded I for one am glad I never knew or worked for him. (would I love to have been a fly on the wall at the employment tribuneral...'I put too much tape on a joint and he fired me!I wasted 3p!) d) bear in mind sugestions are made with the best of intentions - concidering you have a familly business I am suprised you didnt offer your wealth of knowledge earlier, I would have thought an experianced familly business member would at least have known what joints are on a standard cylinder!
You are right stag shouldnt be needed on a new joint...unless it is BSP threaded steel pipework, stag on its own on a hot copper/brass joint will just harden and be verry difficult in the future to remove if needed.
as a side, if your plumbers use 3,4 or 5 turns on 15 mm you must get a lot of call backs for leaking rad valve tails unless you are using the new thick type tape...oh silly me I did quantify that as well earlier.

I'm not a plumber, I'm a mechanic. Didn't fancy the business so went my own way.

And my question was asked and comment made with the best of intentions, there was no need to belittle my grandfather in your reply to it. Most people learned a lot from him, I wish he was here now to help me argue with you. But he's not, so I can't.

And for info, PTFE tape is banned in most of the Oil and Gas industry due to the number of screwed joint failures attributed to its use.

I stand by my 3 or 4 turns comment.

[Bogus]

I'm not a plumber, I'm a mechanic. Didn't fancy the business so went my own way.

And my question was asked and comment made with the best of intentions, there was no need to belittle my grandfather in your reply to it. Most people learned a lot from him, I wish he was here now to help me argue with you. But he's not, so I can't.

And for info, PTFE tape is banned in most of the Oil and Gas industry due to the number of screwed joint failures attributed to its use.

I stand by my 3 or 4 turns comment.

A lot of oil and gas companies and service companies have banned it indeed and instead use a liquid thread sealant called swak. The problem in oil and gas was that people were using it excessively on high pressure systems, up to10000psi and likely higher. They were using it "plumber style" on swagelock fittings which are precision made, and you even had numpties using it take up slack on mismatched fittings. Domestic plumbing is low pressure and the threads tend to be prettly roughly made. Plumbers tend to use the stuff to " create" the thread and it works fine. Even Corgi gas fitters lash it on, and again because the pressures are inches wg, its just fine. I think in the low pressures involved in domestic systems and the non precision threads involved , lashing it on is preferred to having to deal with a leak. In high pressure systems, ( eg hydraulics) if it must be used, your 3-4 turns would be correct. Start putting on too much and you run the risk of not catching enough threads and thats often followed by a catastrophic failure. At low pressures you get leaks rather than catastrophes.

Bogus

[fatfires]

A lot of oil and gas companies and service companies have banned it indeed and instead use a liquid thread sealant called swak. The problem in oil and gas was that people were using it excessively on high pressure systems, up to10000psi and likely higher. They were using it "plumber style" on swagelock fittings which are precision made, and you even had numpties using it take up slack on mismatched fittings. Domestic plumbing is low pressure and the threads tend to be prettly roughly made. Plumbers tend to use the stuff to " create" the thread and it works fine. Even Corgi gas fitters lash it on, and again because the pressures are inches wg, its just fine. I think in the low pressures involved in domestic systems and the non precision threads involved , lashing it on is preferred to having to deal with a leak. In high pressure systems, ( eg hydraulics) if it must be used, your 3-4 turns would be correct. Start putting on too much and you run the risk of not catching enough threads and thats often followed by a catastrophic failure. At low pressures you get leaks rather than catastrophes.

Bogus

correct, I believe I did make the point about poor threads, an there are tapes for water and a different formulation for gas, corse threads (BSP) have little in commmon with engineered threads and the norm is to be parallel, again a need to 'fill the thread'. for hydrolics etc I wouldnt entertain its use, there are many good sealants for that and if the thread is a good'un then bare can be fine too. On gas taper threads a little compound is all that is needed.
In all trades (including mechanics) there will be the 'engineers' who think they know it all, those that use incorrect materials, methods etc and those that just shouldnt be in the trade. Perhaps well intentioned advise from those in the trade should be left to give relevent advice instead of confusing side issues that question professionalism.
Tell you what...dont tell me how to be a time served experianced heating engineer and I wont tell you how to fix motors!
Thanks Bogus for elaberating the difference between plumbing threads and engineered ones.