wiring for twin pump system

[Rob]

Can someone advise the correct way to wire in a twin pump system.

Its a standard s-plan except for small pump for hw cyl and bigger one for CH.

Whats the best way to do it without bringing them both on at the same time?

Thanks!

 

[simond]

You'll need a relay to prevent the backfeeding from Pump A bringing on Pump B.

Alternatively, for basic domestic applications you could buy a Grundfos pump plan twin head with their own wiring centre, and dispense with all motorized valves....