Veco North America, LLC

All Climma air conditioning units are water cooled and require a pump to draw sea water in via a strainer, pass it through the air conditioning unit, and discharge it overboard. If more than one air conditioning unit is installed, a single pump can be used, with switching being accomplished by a Pump Relay. Each size of air conditioning unit requires a minimum flow of cooling water, and the requirements are shown on the Spec Sheet for each unit.

There are two types of pumps: Centrifugal and Positive Displacement.

1. Centrifugal pumps use an impeller spinning a shaft that spins the incoming water within the pump housing, and the centrifugal force of the spinning water forces it out of the discharge fitting. This type of pump is not self-priming and so must be mounted below the waterline and to a strict code of installation criteria if it is to give trouble-free performance. The impeller can be coupled directly to the motor (open drive), or by magnetic coupling (magnetic drive). Magnetic drive pumps are commonly used for smaller systems as there is no shaft seal to wear and require replacement, Magnetic drive pumps are often fully submersible.
2. Positive Displacement pumps use diaphrams with valves or flexible rubber impellers to suck up water and deliver it under pressure. These pumps are self priming and capable of delivering liquids at considerable pressure, but they can be noisy and are typically rated only for intermittent use. However, there are some that are suitable for air conditioning applications where the installation criteria of a centrifugal pump cannot be met.