Polypipe push fit piping for central heating systems

[Jim]

I'm just about to embark on installing the heating system for our house refurbishment.

For my upstairs radiators, I intend to use a polypipe manifold in the airing cupboard to transition from 22mm copper into 15mm plastic and then bring the pipes through the floor joists without joins to under the radiators, then come up to the radiator valves in 15mm copper. The advantage of this approach is an easier installation and fewer inaccessible joints.

My question is, what joint to use for the bend between the plastic pipe running horizontally and the 15mm copper radiator tail? There seems to be a choice between brass compression and using one of the plastic pushfit bends. I'm worried that the pushfit joints won't be reliable and we'll end up with leaks into the ceiling after a few years.

What are there pros/cons?

[fred]

In article , Jim writes

That sounds like a good way to do it.

My personal choice is to use a joint that is as least as strong as the strongest item to be jointed, meaning:

solder or brass compression for copper to copper

brass compression for copper to plastic

plastic or brass compression for plastic

I think this makes the joints more likely to survive under abuse which I view as inevitable at some point in their life and is quite likely for joints to radiator tails.

[Roger Mills]

Either will work. Push-fit is easier to do, but compression fittings are less bulky - and probably cheaper. Push-fit won't leak as such - but you may get a few molecules coming out over a period of time and causing a bit of green corrosion on the copper pipe.

My preference would be for compression elbows as long as you can get at them easily to tighten them properly. Either way, don't forget the inserts in the plastic pipes.

[The Medway Handyman]

Agree with Fred 100%.

As Roger said - don't forget the inserts.

[geraldthehamster]

I don't disagree with what others have posted, but personally I'd use (and have used) plastic push-fit elbows, for ease of use. They're so easy to fit, and in the unlikely event that you had an issue with them further down the line, just as easy to replace.

Cheers Richard

[Grimly Curmudgeon]

We were somewhere around Barstow, on the edge of the desert, when the drugs began to take hold. I remember Jim saying something like:

The neatest push-fits are Tektite, or just use compression elbows.

[Jim]

Thanks to everyone who answered. I think we'll use the compression fittings where we can get to them then.