With a submerged pump, all the energy that enters the pump in the form of electricity must get out eventually in the form of heat. Nearly without exception, the power stated is the maximum the pump will consume, which occurs at peak flow/zero head. In the real world, the power consumption will always be somewhat less. How much less depends on the real flow rate.
To be conservative, simply assume peak power. Practically speaking, it's more liable to be ~1/2 to 2/3 of the power listed.
|