PEX-AL-PEX for hot water return (manifold system)

[elvis80]

Uponor MLCP is fine for secondary return. MLCP is Pex-AL-Pex but not all MLC systems are suitable, check with the manufacturer first.

Thanks Dave. Struggling to get a response from Pipex.

 

[Stigster]

Thanks both. Here are some pics. It's Pipex pipe, but their website wasn't very helpful. It seems to be used for UFH a lot, but assuming that's not an indicator as that runs at lower temperatures?

As the others have said, the multi layer pipe with the aluminium layer can be used for secondary return. The reason some manufacturers state their plastic pipes cannot be used as a secondary return is something like "Continuously circulating secondary return system are 'very different' to a heating circuit as the water is constantly replenished and circulated at high temperatures" or words to that effect.

I think the problem they have is that with a constantly replenished systems you are introducing fresh oxygen into the system and then circulating it at a constant high temperature.

These metal layer pipes are quite different from ordinary plastic pipe, even barrier pipe.

 

[elvis80]

As the others have said, the multi layer pipe with the aluminium layer can be used for secondary return. The reason some manufacturers state their plastic pipes cannot be used as a secondary return is something like "Continuously circulating secondary return system are 'very different' to a heating circuit as the water is constantly replenished and circulated at high temperatures" or words to that effect.

I think the problem they have is that with a constantly replenished systems you are introducing fresh oxygen into the system and then circulating it at a constant high temperature.

These metal layer pipes are quite different from ordinary plastic pipe, even barrier pipe.

Thanks. I can see the potential limitations there. I'm going to try again to get a response from the manufacturer.

 

[Stigster]

Thanks. I can see the potential limitations there. I'm going to try again to get a response from the manufacturer.

That is the best thing to do. Please report back with your findings as it's very useful for us to know. Thanks.

 

[Uheat – Jake]

Here's a technical extract for our PERT-AL-PERT MLCP. Explains the lifetime in good detail.

 

[Dave Marques]

New Uponor Feb 2020 price guide shows a new Seamless Aluminium Composite pipe, next generation Pex-Al-Pex, 'Stronger and allows the pipe to be bent in a much tighter radius'.

 

[elvis80]

Thanks both. Food for thought. Will speak to my plumber (who's concerned about whether it'll work, but hasn't seen it yet) and my builder - who has used it previously but...isn't a plumber!

 

[Chalked]

Have you checked with the manufacturer if it can be used on potable water?
we get 500m coils of a very similar pipe to that, from Wunda floor. But it’s only been certified for use on closed heating circuits. That’s not to say it won’t work or leak. It means the company hasn’t put it through the testing process, needed to make it wras approved.
if it isn't, you could invalidation your insurance, if there was a problem and a claim.

 

[Dave Marques]

Uponor has full WRAS approval.