In an earlier contribution to this discussion, mike ring
wrote:

I've considered the Grundfos Pump Plan - seems very advantageously
priced at plumbworld ATM, and came up with this doc

UPP_Pump_Plan_05_03.pdf

but I don't know where from.

It contains a wiring diagram.

A URL would be *awfully* useful!



I really like the idea, but it's a bit bleeding edge for me...., what
happens if one pump fails in a cold snap?

You lose *either* the HW *or* the CH - as opposed to losing *both* with a
conventional one-pump setup!
--
Cheers,
Set Square