Which plastic pipe is best for central heating?

[yebaws]

Yes, copper is best and I would prefer to use that but I also don't want to rip up my beautiful floor and flexible plastic will push through where copper won't. I realise that I need a barrier pipe to stop air ingress, but there are a range of different types of plastic pipe available and I'm not sure what would be best...PEX? PB? any particular brand? And would I be best to use conventional brass fittings and olives to make connections instead of the push fits with rubber O rings? Heating will run at 65 deg C and I will use copper tails from the boiler (which is actually a heat exchanger)

Thanks!

 

[denso13]

Speedfit is my preference but others will do the job. Use Speedfit fittings as well with the correct inserts.

 

[muggles]

Given that you're almost certainly not going to pressure test it to the manufacturers' specification, and will therefore have no warranty, pick the cheapest one you can get.....

 

[yebaws]

Given that you're almost certainly not going to pressure test it to the manufacturers' specification, and will therefore have no warranty, pick the cheapest one you can get.....

92 deg C at 3 BAR, why not... But seriously, I just wondered what the difference between PB and PEX is and what anybody thinks about using brass fittings and olive for longevity...

 

[muggles]

You misunderstand me, or have confused the pipe specification with the pressure test specification - the manufacturers do not specify that you should pressure test at 92°C and 3 Bar, that's the maximum duty rating of the pipe.

Most specify that you must test at 20°C and Eighteen Bar for one hour, so unless you're going to do that you won't have any warranty and the choice of pipe and fittings is largely academic. For what it's worth, I'd use plastic fittings with plastic pipe, brass compression fittings can twist the pipe just enough to be irritating. PB has less shape memory than PEX, so if you're using coils it'll uncoil more easily

 

[yebaws]

you won't have any warranty and the choice of pipe and fittings is largely academic

warranty is pretty much irrelevant to me - I just want fittings that won't fail in time and plastic unfortunately degrades a lot faster than brass and copper...

Thanks for that about PB & PEX

 

[flameport]

warranty is pretty much irrelevant to me - I just want fittings that won't fail in time

If joints failing is that much of a concern, put individual pipes to each radiator, and take them to a central manifold in a cupboard somewhere.
Therefore no joints under the floor at all, and if (highly unlikely) any do fail, they can easily be replaced.

 

[jamesdean1986]

I know this was a year ago but I'm in a similar situation and really struggling to find answers. My general understanding is that PB is more flexible but PEX is stronger.

What did you go with? Ive got to run 4 pipes - hot and cold taps, and flow for heating.