Centrifugal pumps are among the most reliable pumps available on the market. They move fluids from one point to another through the action of an impeller. Basically, an impeller refers to a set of vanes made in such that they impart a rotational effect on a given mass of fluid. The cyclical movement of the vanes generates a significant centrifugal force that throws water outwards and away from the centre of the rotating impeller. The amount of centrifugal force generated is directly proportional to the speed and size of the impeller. For this reason, centrifugal pumps with large or fast impellers tend to be more powerful than those that come with small or slower impellers. When using centrifugal pumps to pump water, here are some of the common problems you might encounter:
Loss of Prime
Naturally, centrifugal pumps are not self-priming. This means that the pump casing should be filled with water before you start the pump's motor. If there is no water in the pump casing, then the casing fills up with vapour and other gases, making it impossible for the pump to move the fluid. For this reason, most manufacturers design centrifugal pump in a way that some fluid always remains in the pump casing for priming purposes. Loss of prime could be due to leaks in the suction pipe fittings and joints. Examine them thoroughly for any wetness and tighten any loose fittings with a pipe wrench or adjustable spanner. Thereafter, fill up the pump case with water before starting it.
In centrifugal pumps, cavitation is a case where the pump is being starved on the suction side. This is because of a low amount of fluid being supplied to the impeller. Cavitation often leads to small cavities or bubbles around the eye (centre) of the impeller. With inadequate fluid coming in from the suction side, the pump uses up lots of energy, yet the output is very low. Therefore, you should improve positive suction by lowering the suction head deeper into the water.
Low Fluid Speed
Is the fluid discharge speed too low yet there are no leaks? Well, the problem might be with your motor. Check the alignment of the motor to ensure that it lies perfectly across the current line and receiving full voltage. Moreover, examine the rotation of the motor and ensure that is in line with the directional arrow on the casing of the pump. If not, call in a professional to rectify the electrical errors as they could damage your pump.