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The figure is the maximum height of a vertical column of water that the pump could support if there were no other losses in the system.

Flows are given in litres per minute and are based on pumping clean, cold water (or diesel, or oil, when referring to fuel and lubricant pumps), through the outlet bore specified.

Manual: a float switch is not fitted. The pump requires an operator to control the pump by switching it off or on at the mains.

Auto: a float switch is fitted. The pump will turn itself on and off automatically as the water level rises and falls. The float switch must be actuated for the pump to operate. The pump is automatically controlled by a level switch.