Mixing plastic pushfit joints with copper ones

[Richard81]

Hi,

Is it safe to solder a copper joint onto a length of copper pipe that has a plastic push fit (twist type) connector on the other end of it? Is there a minimum safe distance of copper pipe between the plastic joint and the hot end? I'd like to replace some plastic CH joints with copper fittings (for aesthetic reasons) but some are quite close to plastic joints under the floor and I don't want to melt these by blowtorching nearby copper pipe. Can I get away with it or should I forget it?

Thanks!

 

[Plumbstar Tom]

there is a washer in side the push fit so i would disconnect, only takes a second to do

 

[Richard81]

Trouble is, I don't think the push fit is accessible because it's under the floor...

 

[Plumbstar Tom]

use a compression joint instead then as if you do cause a leak and its under floor its a lot of hassle to fix!

 

[Richard81]

Yeah, I guess that's a good compromise (compression nuts aren't quite as elegant as a smooth soldered joint). Mind you, anything would probably look better once painted.

 

[Plumbstar Tom]

a compression joint is better than a leak under the floor though!

If your boxing it in it wont matter if not then yes an end feed joint is by far the best but sometimes things just aren't possible

whack your joint, nuts and olives on, paint it up and it will hardly be noticable

 

[Richard81]

Yeah, you're right. Thanks for the advice.

 

[Guest123]

450mm is the minimum distance to make a solder connection on copper pipe inserted into a Speedfit fitting. Under no circumstance should solder or jointing pastes come into contact or be used near plastic fittings. Use PTFE tape on your compression joints and when connecting barrier pipe to a compression fitting. Also when doing so use copper olives and do not overtighten.
I've just been to a job, where the plumber last year hacksawed the copper tails on a tap and didn't clean his excess flux from the pipework. The burr on the pipe and corrosion of the O ring due to the flux, blew the Speedfit fitting off the pipe and the kitchen was a mess. If you use these fittings properly and follow the manufacturers instructions, they are fine. Sadly too many people are ignoring this and slapping them on without reading about them first.
All my fixes I've been called to for people wrongly installing Speedfit are:
Not giving full slip into the fitting.
Hacksawed pipe damaging the O ring.
Acid corrosion from flux.
Excessive sideload and incorrect pipe clipping - should be every 300mm on a horizontal run of 15mm pipe and not closer than 600mm to the fitting.
Heavily scored pipe from scraping through a wall cavity.
All failures are due to bad practice and should have been avoided.

 

[john.bell55]

Excessive sideload and incorrect pipe clipping - should be every 300mm on a horizontal run of 15mm pipe and not closer than 600mm to the fitting.
.[/QUOTE]

John Guest recommend not closer than 60mm from fitting, to allow for expansion.

 

[Guest123]

I inserted an extra zero in error. It should of course be 60mm not 600mm for clipping pipes. Thanks for pointing this out.

 

[john.bell55]

Thought you had