Replacement of major components, such as the engine, motor, or pump or changing to a more efficient system are most costly. Normally, replacement of major components is not warranted unless the performance rating is less than 60 percent of the standard. The payback period for replacement of major components is typically five years or more. The pumping plant analysis indicates whether or not overall performance is acceptable but does not indicate which component is responsible if overall effficiency is low. Overall pumping plant efficiency can be computed by multiplying the effciencies of the individual components.
Electric motors are relatively effficient and reliable.
Poor pumping plant performance can usually be attributed to low pump efficiency. In the example, the overall pumping plant performance was 86 percent of the standard. The absolute pumping plant effficiency was 57 percent. Internal pump components should be evaluated by a qualified representative of the pump manufacturer. Reduce the number of sprinklers until the proper flow rate is reached.