Water pipe flow from header tank

[Scholsey]

Have a header tank catching plate cooler water which feeds a drinking trough, 25mm pipe with 4m head can't flow quick enough and I have water coming out of the overflow, how much more flow is a 32mm pipe over a 25mm with that amount of head.

 

[Pan mixer]

25 mm pipe is 20mm internal, assuming the same wall thickness 32 mm pipe would be 27 mm internal.

Given the same head the throughput would be in proportion to cross-sectional area.

This would be 3.142 (pi) x 10 radius - half the diameter of course) squared (ie 100) in the case of the first pipe i.e. 314.2mm sq

Then 3.142 x 13.5 squared (i.e.182.25) = 572.6 mm square

So almost double when you take into account the surface area friction in the smaller pipe

 

[ROBINWORKS]

Make sure the ballcock is low pressure