The maximum suction lift of Electric centrifugal water pump is about 8 meters of water column. Some centrifugal water pumps have no self-priming ability, and water must be added for the first use. Although some micro pumps also have self-priming ability, there is often a gap between the marked "suction lift" and the vertical height that can pump water under "the water inlet pipe is full of air", and may even be less than half.

When the water source is lower than or equal to the location of the pump, the pump needs to have self-priming ability. If the water outlet is above the normal water level of the water outlet pool, although the head of the water pump is increased, the flow rate is reduced. Electric centrifugal water pump manufacturers tell you that if the water outlet must be higher than the water level of the water outlet due to terrain conditions, elbows and short pipes should be installed at the mouth of the pipe to make the water pipe siphon and reduce the height of the water outlet.
Electric centrifugal water pump manufacturers tell you that in order to prevent cavitation of the water pump, when the grid voltage decreases, the speed of the water pump decreases, and the head characteristic curve of the water pump decreases accordingly. When the zero head of the pump is lower than the actual head, the pump will not discharge water and the flow will be zero. At this time, all the energy delivered by the motor to the water pump will be converted into heat energy, and the water pump will heat up strongly and will be damaged soon. Therefore, the water pump is not allowed to work at zero flow for a long time.
The influencing factors of electric centrifugal water pump cavitation mainly include the water suction height of the water pump, the resistance of the water suction pipe, the flow speed, the atmospheric pressure and the working water temperature of the water pump installation site, etc. The atmospheric pressure at the installation site of the water pump is generally constant, and the resistance, flow rate, and temperature do not change much. Therefore, the main factor affecting the pump's non-cavitation is the water absorption height.