Compression Joint under Screed?

[rjn57]

Would like advice from any plumbers out there please.

I have just moved a radiator from one side of the room to another. System is drained down and I am tapping into existing pipes (dug down into screed).

My problem is that although I have removed *most* of the water there is still some small amount in the pipes. When I tried soldering a 15mm copper endcap on one of the old rad feeds it didn't really take.

So my questions are:
1. Any solution that will enable me to solder? and if not;
2. Will compression joints be acceptable under a screeded floor?

Roy

 

[gas4you]

Compression joints under a floor in concrete is not really practical in case they weep later on. If there is absolutely no other choice wrap them well in duct tape before screeding over after leaving them visible for 2/3 days to check for leaks.

Have you tried blowing through the pipe to expel the water, or maybe using a wet vac to suck it out then heat the pipe a few inches up from the joint to dry it out before attempting to solder.

 

[rjn57]

Thanks for the reply - I did blow through the pipe and it didn't *feel" like there was any more water in there although they were a bit damp. When I soldered the fitting it eventually turned blue/black and the solder hadn't taken. I did clean joints thoroughly and use flux etc and have soldered many times before.

Maybe I'll try and get hold of a wet n dry vax and see if I can remove any more water.

I must admit I won't feel happy with compression sjoints under the screed.

 

[giblets]

A tip from an old plumber now sadly fallen off his twig.

Push a plug of bread up the pipe. This will absorb the water long enough to solder the cap on.

Might sound daft - but it actually works!!!!!

 

[gas4you]

A tip from an old plumber now sadly fallen off his twig.

Push a plug of bread up the pipe. This will absorb the water long enough to solder the cap on.

Might sound daft - but it actually works!!!!!

Funny that, I was actually told that this morning by another plumber, I didn't believe him at first, but you have now confirmed this, egg on my face

 

[namsag]

If you had a bit of bread dave you could have put the egg on that instead of your face.. .. Bread trick an old one was told it nearly thirty years ago . Trouble is it can sometimes get stuck just don`t pack it to tightly in

 

[gas4you]

 

[doitall]

Thin bit of plastic pipe stuffed down the pipe and you can syphon the water out

 

[clf-gas]

The bread trick is as old as the hills, though I would'nt use it on heating pipes, thats asking for a blockage.