Circulation pump

[grant lyons]

Can anyone tell me what impact running a circulation pump with a larger diameter bore would have?
Currently running an old grundfos 15-6 on 22mm with 1 1/2 threads but looking at a lowara ecocirc 25-6.

 

[oldbuffer]

Probably not much. The Grundfos replacement (UPS 3) will push 4 cubic Metres / minute, the Lowara 3.2.
Both have 1 1/2" connections.
If the old Grundfos is failing, you should see some improvement, otherwise I'd leave it alone until it dies.

 

[Gasguru]

You'd have to look at the pump curves for the Lowara but comparing Grundfos 15 and 25 nominal diameters makes no difference to performance...the 25 bore is really just a way of extracting more profit from commercial installers.