Pre-Startup Considerations

In centrifugal pump operation, one of the key problems we need to consider is how to get water to the pump on the suction side. If the water level (on the suction side) is above the pump, really do not have this problem. But if it is not, then we have a problem. It is easy for a centrifugal pump to pump the water out of its discharge - but only if water can somehow be fed into it on the suction side. If the water level on the suction side is below the pump, then the pump is not able to suck water into its body to pressurize it. This issue is the key point in the discussion that follows.

To start a pump, operators usually line the pump up and press the start button, and all is well. The term "lining up" means that all of the suction and discharge side valves are in open position. Though it works most of the time, but in some cases such an approach can create problems. In this section we will discuss some issues which operators should be aware of regarding pumps with suction lift configuration. The pumping systems which are designed with a static suction head (on the suction side) are far easier to operate since the static head on the suction side pushes water into the pump.

The term "line-up" indicates opening or closing of the valves as necessary. For example, the suction valve must be open and drain valves must be closed before you can start up a pump.

Pumping Systems With Suction Lift Configuration

Pumping systems designed with suction lift conditions are far more prone to operational problems than those with suction head design. Here are the key things to watch for.

Suction Piping

Sometimes suction piping develops holes due to corrosion. This makes the pumps inoperational. Inspect suction piping to make sure it is in good shape. Also check piping to ensure there is no obstruction (such as a half-closed valve or debris.)

Water Temperature

An increase in water temperature effectively increases the suction lift. If water temperature increases considerably, consider a reduction in the static suction lift to compensate for the higher temperature.