What happens to flux in cold water pipes?

[Madrab]

bore restriction from poorly soldered joints

You're right, simply down to bad soldering practices. That's the main reason to only flux the pipe and not the fitting when soldering. The main culprit for solder in the pipe is when flux is applied to the fitting and not/as well as the pipe. When the flux filled fitting is pushed on, the pipe squeezes the flux inside the pipe and then the solder is drawn in when heating. When it's only on the pipe the flux is pushed to the outside of the pipe and wiped off before soldering so the solder is only drawn into the gap between the pipe and fitting.

I will always prefer to solder instead of push fit or compression where possible (of course compression's been around almost as long as copper soldering has) as I prefer a system that can last 50 years or more. I still add to and alter soldered copper water systems that have been in leak free service since the late 50's/60's and earlier in some cases typically found in the old pre-war Glasgow tenements where the lead was replaced. Never seen copper pipe so thick in all my life, that and the old 3 piece riveted hot water cylinders - great down the scrappy

Unfortunately I couldn't say that for any of the legacy plastic/push fit/compression system I've ever come across, especially the systems put in during the copper shortages 70's>80's - Brown plastic push fit, black/gey alkthene (solvent and compression), s/s pipe w/compression are all failing now after 30 odd years. Even some of the 'new builds' from the 2000/2010's where their plastic pipe and fittings are now starting to fail now, guess the proof is in the pudding.

 

[MeldrewsMate]

The reason for this is for maintainance purposes, when changing some components it is necessary to disconnect the pipework below the boiler, also in some cases the outlet from the boiler connection is plastic and soldering the final connection will damage it, the reason for minimum lengths of copper connected to the boiler is the plastic pipe cant always hold up in the event of the boiler over heating

Agreed, and add to that the rubber seals between the boiler's copper tailpipes and the (room-sealed) casing which will be damaged by the heat of soldering.

 

[MeldrewsMate]

I would imagine (because I have very little evidence to date) that the EPDM 'O'-rings in a plastic push-fit system will slowly harden over time, as will the plastic pipe. Given the regular expansion and contraction of the pipe during many many heat cycles in a domestic heating system it is not beyond the wit of man to foresee this condition causing a weep of heating fluid at the joint, detected by the householder as a stain on the ceiling that won't go away. Once diagnosed it is easy to cut a small patch out of the damp ceiling, make a relatively quick replacement of that fitting, patch, replaster and decorate - easily fixed....

...then consider that a typical 3 bedroomed house may have 40 such fittings and, after 20-odd years of use there may be a fitting failure rate of 1 every three months. And for those 'imagined' reasons I shy away from plastic systems. Sure, they have their uses, but the Luddite within me still specifies copper unless there's a good reason not too.

 

[HERTS P&D]

The last time I sorted out a failed fitting the neighbours had also called out a plumber...they assumed they had a leak but the water had run through the party wall

I was called to a property due to the neighbor seeing water coming over the threshold of the front door. The householder was 300miles away on holiday and had to drive back. She came back to find the whole downstairs of the house having 75mm of water due to a plastic joint popping off under the kitchen sink.

Andy

 

[BlueLoo]

I notice that trades on here can have a specific favourite when it comes to the what and the how, which becomes the go-to regardless of the situation.

I like to look at the pros and cons and use accordingly.

My priorities and situation dictate that PEX/Compression is the best solution. This is because i can decouple the fittings at will to allow me to reconfigure the piping if needed, or to clean out corrosion and debris.
I have yet to find any dirty or furred up PEX piping in my house. Every copper pipe and brass fitting has been furred up, the copper especially so.

I don't need a special stick for my plumbing because the PEX piping doesn't fur up and i can remove the comp fittings easily if required.

Also, i notice the PEX piping to be quiet. Any copper piping makes some noise. It's a notible difference.

I also like the way PEX piping is to some degree, self limiting in strain. Copper is terrible in this regard.

But, each to it's own situation.

 

[bernardgreen]

I was in a builders merchants a few years ago and listened to a company rep talking ( boasting ) to staff about how good his company's plastic pipe and fittings were.

Asked if he had plastic pipes in his house the answer was no, it was all copper. He went on to say copper was better but if installers wanted easier faster installs then they would go to plastic. They ( installers ) did not have to live in the house they plumbed with plastic.

 

[Exedon]

I bet they don't like the price of the press fittings.

Andy

Horses for courses for a start fittings cheaper than push fit & quicker than soldering.
If you owned a a large grade 1 listed country house full of antiques would you want a heating engineer using a blow lamp (no matter how carefully)when a perfectly good alternative existed?

 

[Deleted member 292770]

I can't help but wonder why soldered fittings/copper pipe are still used

longevity.reliability.

 

[Deleted member 292770]

All fluxes used these days for potable water must be water soluble, once flushed for a minute it should be fully clean.

Copper v plastic .... This is a long long standing argument that's done to death - There are pro's and cons for both and each has it's place IMO

Copper is resistant to vermin and mechanical damage. Copper is fully recyclable. Copper is more heat resistant, longer lifespan, is best material for use outdoors, is more resistance to solvents, etc .......
Plastic also has it's benefits though - Cheaper (pipe not fittings), ease of install , quicker to install, more resistant to corrosives, more DIY'able (earns me more money when it goes DIY wrong ), etc .....

Soldering though is by far the best and most long term reliable and trusted connecting method for copper pipe, especially if it is to be inaccessible. Once soldered properly, soldered copper is then considered a permanent part of the pipe. Compression and push fit aren't.

Which boiler OEM recommends compression and where is considered to be on the heating side?

50 years guarantee on john guest now if im not mistaken.

 

[Madrab]

50 years guarantee on john guest now if im not mistaken.

Except like most pros we see so many failed pushfit joints, a properly soldered joint will never leak, DIT pushfit and even some so called pros using pushfit have a very high failure rate, have probably heard every excuse from Manus reps about why their fittings failed, always the installer, never admit their products are sub standard

This is happening more and more especially as the kit is getting older ... it's very hard to prove that it wasn't an installer fault (and I'm sure some will be). Unless everything is documented, photo'd and signed off by someone they recognise then it's hard to prove every instruction was followed and therefore it was the product that failed, so the guarantee isn't really worth that much TBH.

Wish it wasn't failing in the field, trust would then be much higher.

 

[Harry Bloomfield]

Except like most pros we see so many failed pushfit joints, a properly soldered joint will never leak, DIT pushfit and even some so called pros using pushfit have a very high failure rate, have probably heard every excuse from Manus reps about why their fittings failed, always the installer, never admit their products are sub standard

Not a plumber, but I have done a fair bit of plumbing and lead cable jointing over my working life. I would never consider anything other than copper and mostly soldered joints acceptable in my home. Very unlikely, but if I was ever in the position of needing a plumber to do any work in my home and they arrived with plastic pipe, they would be sent on their way. I only have copper pipes in my home, the only compression joints are accessible and easily checkable. There is only one bit of plastic in the place/ one push fit - a few inches long as part of the electric shower.

Our previous electric shower also used push fit. One day we took a trip to the coast and on our return the push fit was leaking, bathroom was soaked, the toilet below it was soaked. I managed to dry it all out without any serious damage.

 

[BlueLoo]

Horses for courses

/Thread.

 

[DP]

Hmm.

I could have sworn my Potterton boiler manual tells the user to use compression fittings only.
On re-reading the manual, it does say this but its for connection only (obviously).
My Bad.

I thought it an odd requirement and had assumed it was to mitigate bore restriction from poorly soldered joints......
Likewise, i am aware that some boiler manufacturers ( again, iirc) ask for copper within a certain radius of the boiler.

What happens to your plastic pipe if boiler goes critical and temperature of circulating water is pushed to 100 or higher degree centigrade. I hope and trust the plastic pipes are not connected directly to your boiler

While you work to HIGHEST level of competence in your own mind, would like to see you involved in carrying out duties you are so skilled at in clients premises.

 

[BlueLoo]

What happens to your plastic pipe if boiler goes critical and temperature of circulating water is pushed to 100 or higher degree centigrade. I hope and trust the plastic pipes are not connected directly to your boiler

While you work to HIGHEST level of competence in your own mind, would like to see you involved in carrying out duties you are so skilled at in clients premises.

What happens is well understood and follows the laws of physics.

British standards dictate how to connect to domestic boilers and as always, the correct way is: it depends.

As to your question, Charles law is the answer, meaning, nothing will happen if the system has been installed correctly.

Therein lies the rub, eh?

 

[ianmcd]

British standards dictate how to connect to domestic boilers

Really ? and as a side note the republic of Ireland is not part of great Britain so why would British standards apply to you ? and British standards dont apply here either when installing and purchasing boilers