Further thoughts against paralleling such pumps:
If the internal check valves in one pump fails then the fluid will
flow retrograde in the pump that failed.... and damn little volume is
pumped by the pump that remains intact.
Typical industrial installation of such a 'system' would require a
block and bypass system of cocks/valves and bypass/lock-out piping.

In article , Steven Shelikoff
wrote:

On Mon, 12 Apr 2004 13:33:26 -0000, Larry W4CSC wrote:

(Steven Shelikoff) wrote in
:


That begs the question why are you going to put two pumps in parallel if
you only want to run one at a time?

Steve


Backup?

Then I wouldn't put them in parallel without isolation valves. Even if
it works when both pumps are good, you don't know how the pump will
fail.

Steve