Generally, the focus during  split casing pump  installation is on the equipment rather than the piping supplying it. However, if the pump is installed without the correct piping, it may fail prematurely and repeatedly during its service life.

Follow these six simple rules to avoid premature pump component failure and the associated pump piping hazards.

1. Keep the suction line as short as possible

Allow a straight section of 5 to 10 pipe diameters between the pump suction and any obstructions in the suction line. Note: Obstructions include valves, elbows, tees, etc.

Keeping the pump suction line short ensures that the inlet pressure drop is as low as possible. Straight sections of pipe provide uniform flow velocity across the entire pipe diameter at the pump inlet. Both are important for achieving optimal suction results.

2. The pipe diameter on the suction side should be ≥ the pump inlet size

The pipe size is a balance between cost and friction losses. Larger pipe diameters cost more, while smaller pipe diameters cause more friction losses to the system. In terms of diameter, the diameter of the outlet line should usually match the outlet flange on the split casing pump, but can be larger to reduce friction losses and lower system pressure. On the suction side, the diameter can be the same, but engineers often choose to go one or two sizes larger, which requires an eccentric reducer. If the fluid viscosity is greater than water, a larger suction line on the suction side is often selected. This also helps to create a uniform flow to the pump and avoid cavitation.

3. Use an eccentric reducer on the suction side

When a pipe size conversion is required, consider using an eccentric reducer on the suction side of the pump. When the flow comes from below the pump, the reducer will be installed top-flat. If the flow comes from above the pump, the reducer will be installed bottom-flat. The purpose of this design is to prevent air pockets from forming on the suction side of the pump.

4. Eliminate elbows installed at and near the pump inlet nozzle

Install a straight pipe section of 5 to 10 pipe diameters between the split casing pump inlet and the elbow. This helps to eliminate "side loading" of the pump impeller and create uniform pump axial bearing loads.

5. Eliminate the possibility of air entrapment in the suction line

5-1 Maintain adequate fluid level in the supply tank to prevent vortex formation and air entrainment.

5-2 Avoid the formation of high cavities in the suction line that may entrain air

5-3 Keep all piping and fitting connections tight under suction vacuum conditions to prevent air from entering the pump.

6. Ensure that the piping layout does not cause stress on the pump housing

The pump should not be used as a support for the suction or discharge piping. Any stress caused by the piping system on the pump housing will greatly reduce the life and performance of the pump.

Remember that improving the performance of the pump can help compensate for improper piping layout on the discharge side of the split casing pump. However, problems on the suction side can be the source of repetitive failures and can cause problems for many years if not properly resolved. Suction side piping problems are the cause of most pump failures.