Site acceptance test items for ISG vertical pipeline centrifugal pumps ensure the installed unit performs as intended under real operating conditions, rather than relying only on factory test data collected under ideal lab environments. Many installation teams skip structured on-site verification, only to discover hidden alignment errors, suction side issues, or performance deviations after the system is handed over for continuous operation. A properly executed field test covers hydraulic, mechanical, and system integration checks that confirm the pump is ready for reliable long-term service.

Pre-Test Installation and Piping Verification

Before starting any formal performance test, you must confirm the physical installation matches all design requirements to avoid invalid test results or accidental equipment damage. This step checks that suction and discharge piping do not impose unnecessary mechanical stress on the pump casing, which can cause casing distortion, shaft misalignment, or unexpected vibration during operation. You will inspect all flange connections for parallelism, confirm that pipe supports carry the full weight of the piping instead of transferring load to the pump body, and verify that all gaskets and fasteners are installed with correct torque values.

You also need to confirm proper inlet flow conditions before proceeding. At least seven straight pipe diameters should be present between the last pipe fitting and the pump suction flange, to ensure uniform velocity distribution at the impeller eye. All strainers should be cleaned and free of debris, all vent points on the suction side fully opened to release trapped air, and the entire suction line completely flooded before the motor is energized. Any flow disturbance or residual air in the inlet will skew flow and head readings, and in severe cases, trigger cavitation that damages hydraulic components during the test.

Hydraulic Performance and Operating Point Validation

Once pre-installation checks are complete, you can proceed to map the pump’s actual field performance against the guaranteed operating points specified in the technical documentation. This test sequence starts with the discharge valve fully closed, then opens the valve in gradual increments to capture stable readings across zero flow, rated flow, maximum continuous flow, and several intermediate points along the expected operating curve. At each stable condition, you record flow rate, suction pressure, discharge pressure, power draw, and actual rotational speed, then convert all measurements to standardized values to account for minor differences in fluid temperature and running speed.

You will pay special attention to performance behavior outside the nominal design point. Confirm that the pump delivers stable head across the full expected operating range, that power input does not exceed the motor’s rated limit at any possible operating condition, and that no unexpected curve instability or head drop occurs at higher flow rates. This step also verifies that the system curve and pump curve intersect within the recommended operating window, preventing the unit from being forced to run continuously in a region that causes accelerated wear, overload, or persistent cavitation.

Mechanical Operation and Dynamic Stability Check

After confirming hydraulic performance meets requirements, you move on to verify the pump’s mechanical behavior under continuous rated operation. Run the unit at its normal design point for a sufficient duration to allow all components to reach thermal equilibrium, then measure vibration velocity at the bearing housing in horizontal, vertical, and axial directions. Any sudden spikes or inconsistent readings across different measurement axes usually point to residual misalignment, unbalance in the rotating assembly, or structural resonance between the pump and adjacent piping.

During this continuous run, you also monitor bearing temperature trends, seal performance, and overall noise signature. Bearing temperature should rise gradually and stabilize well below the maximum allowable threshold, with no steep continuous climb that signals insufficient lubrication or internal clearances set too tight. The sealing system should maintain controlled, acceptable leakage consistent with the specified design, with no visible dripping or spraying that indicates improper seal installation or damaged sealing faces. You also observe the unit through multiple start-stop cycles to confirm smooth acceleration, no abnormal reverse rotation after shutdown, and no unexpected movement in the baseplate or mounting structure.

System Integration and Safety Interlock Function Test

The final set of site acceptance test items verifies that the pump works correctly as part of the larger system, not just as an isolated standalone unit. You test all local and remote control functions, including start, stop, speed adjustment if applicable, and emergency shutdown triggers, to confirm every command executes reliably with no delay or unplanned response. All associated protection devices, including overload protection, low suction pressure interlocks, and high bearing temperature alarms, are simulated one by one to ensure they activate at the correct setpoint and trigger the appropriate protective action.

You also confirm that the installed unit does not create adverse effects on the rest of the system. Check that pressure transients during startup and shutdown stay within acceptable limits for connected piping and components, confirm that no unexpected vibration transfers to adjacent equipment, and verify that all field instruments provide consistent, accurate readings back to the central control system. These integration checks ensure the pump not only meets its own individual performance guarantees but also operates safely and reliably as a fully integrated part of the entire fluid transport loop.