"Jeff Lowe" wrote in message
...
snip
Since these are just turbine pumps, there is no difference as far as the
pump is concerned as to the location of the restriction on either the
input
or output.
snip

I have often wondered about that and assumed that by restricting the input
the pump would be able to empty the chamber faster then it could fill it
causes the chamber to be a mix of air and water, whereas if you restrict the
output, the chamber will retain more water and less air. Surely both ways
make the pump work a bit harder, but it seems to be restricting the output
is better for it then restricting the input.

BV.