Ignoramus31823 fired this volley in
:

i


I still want to know why the check/flow would:
1) Cause the system to take (much) longer to pump up, and
2) "Waste energy".

If you install a check valve/flow-control between the two tanks, so that
the reserve tank can only be filled through a small restriction, but can
dump instantly, any time its pressure is higher than 'system', then
where's the loss?

The small tank will pump up in about the same time as before, with the
only 'loss' being the small flow into the larger tank. The big tank comes
up to system pressure slowly; and as slowly as you want. Then, if you
demand more than the small tank can provide, the reserve will dump
_freely_ (without any significant pressure loss - maybe 1/2 psi) back
into the system.

This is a pretty common way to provide reserve short-term capacity
without increasing pump capacity.
???

So, (I mean it) please describe the problems so I can critique the method
myself. I just don't see the losses or problems you describe.

LLoyd