When shopping for a watermaker low-pressure boost pump, clients often want to know how to choose, especially when their original pump has been discontinued. We have used our years of experience to take the guess work out of the process.
Almost all watermakers use a boost pump to supply filtered raw water, under modest pressure, to the high-pressure feed pump. High-pressure plunger-style pumps require positive pressure at their inlets, otherwise they may cavitate and destroy the seals and plungers. Too much supply pressure can also cause damage to seals and/or valves.
The pumps we offer all have a Maximum flow rating. While this is useful for choosing a pump, it does not tell the whole story. If your watermaker has a high-pressure feed pump that flows 2.5 GPM, you might be tempted to choose a boost pump that has a maximum flow of 5-15 GPM. This would be a mistake, because all centrifugal pumps produce less flow with increasing pressure. One must consider the pressure drop across the pre-filters. Don't forget, as pre-filters age and accumulate sediment, the pressure drop increases. If you don't want to be changing filters frequently, a higher capacity boost pump is needed.
On the other extreme, choosing a boost pump with too much capacity can damage the high-pressure feed pump as I said above. We are looking for the sweet spot of boost pump capacity. In the video below, we show how you can use our Product Filters to help find the right sized pump. In the example we are looking for a boost pump for a system flow rate of 2.5 GPM.
As always, if you have any questions please Contact Us.
Happy cruising!
Tim