Choice of pipe for hot water secondary/recirculating system

Failte · Monday at 7:41 AM

What plastic based / barrier pipe can you use in a hot water secondary/recirculating system. I note Hep20 and Polypipe make it clear in their specs it must not be used. Other than copper what do you use.

ShaunCorbs · Monday at 8:51 AM

Failte · Monday at 9:14 AM

thanks very much

windyboy · Monday at 9:35 AM

Also can't use JG Speedfit.:

1

What can happen if you do use (some type of) plastic pipe on a recirculating system:

RBG · Monday at 10:14 AM

Is that due to the constant high temp?

Failte · Monday at 10:20 AM

I have spoken to the manufacturers polypipe etc and it is because of the higher content of oxygen in the water, it wears the joint connections away and it can short time or a longtime so they say. I wondered if it is like cavitation your get with ship propellors?

windyboy · Monday at 10:23 AM

My understanding is that it's the combination of of high temp plus regular replenishment of water (when hot water is drawn from the system). That means that the circulating water is well oxygenated, which can cause degradation of the plastic. So JG Speedfit (for example) is ok on closed central heating circuits but not recirculating HW.

windyboy · Monday at 10:24 AM

Sorry to repeat. Was typing when Failte posted.

Choice of pipe for hot water secondary/recirculating system

Failte

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Failte

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Failte

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