Abstract: The centrifugal motor pump unit, our case study, is a rotating machine, which thanks to a bladed rotor, increases the kinetic energy and projects, using centrifugal force, the liquid at the periphery on the volute. At the exit and with the help of a divergent, a large part of the kinetic energy is transformed into driving pressure. This equipment currently occupies a prominent place in water pumping stations. These installations are considered as a main ring in the chain of hydraulic circuits. They have an important role in the extraction, transformation, and transfer of water between different points. However, without effective maintenance, this equipment cannot render an acceptable service and the populations will not derive the expected benefits. In addition, the equipment will have a very limited lifespan and the investments will be wasted. As a result, an effective maintenance plan is essential for the proper functioning and proper operation of the pumping installations. The aim of this study is to assess the availability of critical elements of a motor pump system after 24 months in service at a water pumping station located in the city of Constantine in eastern Algeria. In this study, we'll use the graphical tool SADT (Structured Analysis Design Technique) to identify the various subsystems and components of the motor pump system, a Pareto chart analysis and then a failure mode, effect, and criticality analysis (FMECA). This analysis helps us to investigate failure patterns associated with each component in order to choose the appropriate plan of action.

Key words: FMECA, SADT, Pareto diagram, maintenance, availability, motor pump, pumping station