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What Pipework to use for Installing new Overflow for Expansion Tank

Postby diy_div » Wed Jun 05, 2019 2:20 pm

I need to replace the expansion tank in the loft. The current one uses 22mm copper for the overflow, because the new tank isn't exactly the same shape as the old one, I don't relish the idea of trying to bend this to fit, getting all the angles just so to avoid any stress on the plastic tank. So I was wondering about the alternatives.

Flexible plastic pipework is rather more attractive. A 3m piece would be enough to reach the outside world without needing any connections. However, I have read that plastic is quite sensitive to UV, and degrades quite quickly. The front of my house is south-facing, so it would be exposed to quite a lot of sunlight.

Is there any way to protect it from the sun ? A sleeve of some sort, or tape. Or is it not really a problem in practise for an overflow ?

Perhaps a stupid question: is 22mm plastic pipe flexible enough to bend to fit into a car for transport ? It didn't seem all that bendy when I had a look in Homebase, but it's also available in coils, so ..?

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Postby htg engineer » Sat Jun 22, 2019 8:08 am

It depends on your setup. But the pipe outside is normally minimal, 4-5inches.

If you need to run 3m of pipework externally, copper will look better as the plastic will bend if it ever does fill with water.
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