having fitted a smaller radiator to replace a leaking one, i had to make adjustments to the copper piping and decided to use those polypipe speedfit joints to save messing around with trying to solder the old copper pipe back in place.

i'm now in the position of joining the poly back into the old copper network. will i simply push the copper into the poly elbow..? will it withstand the pressure of the central heating system ...? or is there a special copper to poly connector i need to get?

as there's no olive or rubber on the 15mm copper, what does the poly joint grip to? is it just suction ..?

Just make sure that the copper pipe has no swarf or sharp edges and preferably has an inturned edge (if it has been cut with a proper pipe cutter then it should be fine) then just push it home, the grip is provided by teeth inside the plastic joint.

The poly pipe push fit have the O ring inside and a series of teeth to grip the pipe.
Try it, the harder you pull the pipe the more the fitting resists.

Very important , ideally you have cut the copper with a cutter as it rounds the edge off, if you have used a hacksaw be sure to remove the square edge or it is likely to displace the O ring.
Try and measure the depth of the fitting and mark on the copper pipe so you know it is seated far enough in the fitting.

If using plastic 15mm pipe make sure to match the pipe inserts to the same manufacturer as although all the external the same(15mm) the internal bore sizes are slightly different, VERY IMPORTANT!

thanks guys .. i've slotted one end of the rad home .. though these poly pipes feel flimsy to me, too much movement even when tightened the plastic pipes still turn in the speedfits... obviously i can't try that with the copper 'cos the other end is soldered but.. i'm hesitant to turn the water back on...

Thats correct. the plastic pipe will still be able to rotate.

grey o white fittings?
Some do have an optional locking system with what looks like a nut, most don't however the really on the o ring and teeth.

the fittings are white... and seem to turn a little at the base as if to tighten ..?? anyhoo .. at first run i flooded the living room... all the poly joints were good ...

the leak came from the radiator fitting that wasn't tightened enough cos i had overdone the PTFE and the nut couldn't go any further.....

so ... i've mopped up and drained off... time for another fiddle and wallow

The white fittings are just push fit only.You have done it right.
In theory there should be a retaining clip between the body of the fitting and the collar, often not fitted though.Sadly think they only sell em in 100 packets s dont worry.
Fingers crossed this time then.

well the heating timer has kicked in and fortunately there are no leaks but.... with no air in the system (all rads bled) the radiator i'm working on is NOT getting warm...?

all valves open too? any ideas please?

Yep..an airlock in the pipework that runs to the radiator. Common thing when you drain and work on a rad. As you said there will be no air in the rad as you will be filling it with water from the pipework that hasn't the airlock. U need to flush it around or give it a while and it'll move to the rad by gravity. Turn off the valves to the other rads which are closeby and if possible turn up the boiler thermostat and pump speed.

Thanks for the help !!!

i turned off local rads .. still no joy .. the new rad failed to get warm. in the end i had to cloase all BUT the new rad and that gave the pump the assistance it needed in ousting the air... and NO LEAKS !!

Yayy... huge thumbs up to all that helped by adding experience gained through similar frustrations.. CHEERS

Thanks for the help !!!

i turned off local rads .. still no joy .. the new rad failed to get warm. in the end i had to cloase all BUT the new rad and that gave the pump the assistance it needed in ousting the air... and NO LEAKS !!

Yayy... huge thumbs up to all that helped by adding experience gained through similar frustrations.. CHEERS

Some airlocks can be stubborn to shift but glad its now sorted. and you've saved some money by doing it yourself