New Water Main

[b21playa]

Hi all

If fitting a new water main, is it worth laying the largest (32mm) pipe instead of 20mm or 25mm?

 

[Charnwood]

the largest (32mm) pipe

Not even close.

25mm should be adequate for a normal domestic application.

 

[b21playa]

the largest (32mm) pipe

Not even close.

25mm should be adequate for a normal domestic application.

Meant largest usually seen the the normal shops

so 25mm will give a good flow rate as I would be looking at a 300l unvented tank

 

[mfarrow]

Get your pipe bores: http://www.areco.co.uk/water-pipe.htm

Then calculate your pressure drop, given your assumed flow rate: http://www.pressure-drop.com/Online-Calculator/

20 litres/min is considered a good baseline for calculation purposes, so I would use that as your flowrate.

But how much you notice the pressure drop will also depend on the static pressure in the house before you turn the tap on. So 0.2bar drop on a mains with 1 bar static will be 20% drop, but on a mains with 5 bar static it will be only 4% pressure drop, i.e. hardly noticeable.

The size of your tank has nothing to do with it, just means how much hot water you can draw before it starts going cold. Big rainforest shower heads will run the shower cold more quickly though.