32mm or 25MM MDPE

31 May 2007
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United Kingdom
Hello Everyone

I currently have an incoming lead water main up to my internal stopcock, after the stop cock I have what appears to be 25mm mdpe running to my loft where it splits off into 22mm to feed my unvented cylinder.

Is there any advantage in terms of flow rate for my cylinder pressure etc if I replace the lead mains with 32mm mdpe instead of 25mm mdpe.

Or should I just use 25mm mdpe.

The run of the lead pipe is about 8meters, the run of the internal 25mm is about 10-15m.

Once the lead enters the property it goes under my living floor boards between the joists, would I need to lay the new mdpe in ducting even inside my house? Would insulation also be required?

Many Thanks
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You dont say the lead size!

Replacing it will effect a considerable improvement and best in 32 mm too.

Has to be insulated in unheated areas like underfloor and lofts!

Thanks for your reply

As I was pulling the pipe through its gotten a little scratched, nothing too deep but minor surface blemishes that you can feel.

Is this going to effect any joints I make?

What woud you suggest I do about this if it is an issue, this is on the internal runs, it is going to be put in ducting on the outside of the property.

Many Thanks
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You should always protect plastic pipe from scratches which can make joints leak.

I have not done it but perhaps very fine emery paper might solve the problem.


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