Glenn Ashmore wrote:

... Has anyone
ever used the washdown pump as a watermaker boost pump?

Jim Woodward wrote:

As you certainly know, broadly there are two classes of pumps, high
pressure / low volume and low pressure / high volume.

I agree, although the distinction between positive displacement & nonPD is important for several
reasons.

Most booster pumps are non positive displacement so that they don't overpressurize the inlet
side of the main pump casing. They can also supply positive flow over a wider pressure range,
such as delivery to several subsystems.

Another nice thing about non positive dispalacement pumps is that they can have flow through
them when not running, and can readily be primed from either side.


The former is
good for water pressure, washdown and fire while the latter are used
for bilge and sump applications. The best example of this difference
is the Jabsco diaphragm pumps, where you can buy the same motor and
frame driving different belt pulleys and diaphragms -- a single spare
motor can back up both your freshwater and sump pumps....

Now I suspect the watermaker doesn't care much about pressure (there
are so many variations today that I can't say for sure) and might even
be upset if you had too much, but it does want a certain volume and
minimum air. So, offhand, I'd suggest the AC cooling water pump
rather than the washdown pump.

Agreed, with the caveat that the AC cooling pump might be alternating current whereas Glenn
might want to run his watermaker on 12V DC.



But, you have a better way to make the choice -- look at the specs on
the manufacturer recommended watermaker booster pump and then pick the
pump you have that is closest.

Too logical here. Aren't you even going to call anybody names?!?

Fresh Breezes- Doug King