Soldering joints

[JMM]

I have some slightly dripping compression joints, they wont tighten anymore and they need replacing.

When I drain the system, I would like to replace them with pre-soldered elbows.

I heared a rumour that it is not a good idea to use pre-soldered joints on pipework that still may contain a bit of water, as when the blow torch heats up the joint, the water can corrupt the soldering process.

Is this true? Is there a good way of soldering joints onto central heating pipework that may still contain traces of water or should I replace the joints with more compression joints.

Any help will be much appreciated.

Cheers..... John

 

[DAZB]

Why don't you use Push-Fit fittings instead ? You can even get Copper Push-Fit parts now. Have a look in the Plumbing section of a Screwfix magazine ( page 171 of the latest issue) . Very easy to use and no flames needed.

 

[Anton]

I tried the push fittings when I did the bathroom. Very good......BUT and I can only speak from my own personal experience, if they do not work/take/fit, call it what you will.(and 2 of them did just that) You have to cut them off, nightmare! and I personally wouldn't use them again.

 

[breezer]

I heared a rumour that it is not a good idea to use pre-soldered joints on pipework that still may contain a bit of water, as when the blow torch heats up the joint, the water can corrupt the soldering process.

Is this true?

Thewater in the pipe does stop the solder from "sticking" the way round it is to heat the pipe with a blowlamp to boil the water off, but you can only do this if the pipe has an open end for the steam to escape. Personally i would use compression joints. (you will probably have to cut the existing olives off)

Incidentally pre soldered joints are called "yorkshire fittings", but you should use more solder / flux to be sure

 

[DAZB]

The copper Push-Fit fittings do come off without cutting the pipe.You can use a special Release Tool that costs about half a quid but I have got the plastic ones off by hand more times than not. If you are still needing advice ask at your local Plumbing Merchants and see what they think of them.

 

[MANDATE]

No problem using pre soldered joints,If the system has been drained there is no water.
If dealing with horizontal pipe lower the open end a little to get rid of any water then raise it so anything left runs away from the joint,
Water in a vertical pipe needs to be about 9in lower than the joint your soldering, if you can't drain it away use a syringe and plastic tube to suck it out.
Make sure to clean and pre solder the pipe end before fitting your pre soldered coupling or elbow.
Don't forget the flux and if theres achance of burning anything then shield it ceramic tiles or flame proof mat

 

[data-man]

The trouble with replacing a compression fitting, is that it leaves the olives and nuts on the remaining pipe. The pipe will need to be cut back to get these items off the pipe, and straight unions used to make up the length back the the elbow. I would go with soldered joints if there is enough room around the pipe. The main trick with soldered joints is, very clean pipe, flux on the pipe, even heat distribution around the pipe, and when you see the Green flame, the joint is done. A much neater job than compression fittings.

 

[masona]

Have you try putting White Hawk Jointing Compound onto the olive ring and then tighten it up again.If this failed,the olive ring had been overtighten and damaged.If you are careful you can cut the olive ring with a fine hacksaw without cutting into the copper pipe & clean up with new olive ring + White Hawk Compound.

 

[JMM]

Thanks for all the advice.

I have used soldered joints for the pipework upto the radiator valve and used a copper pushfit joint to connect the pipe to the existing central heating pipe. Much neater job.

Cheers....John