Correct startup, operation and shutdown are especially important for canned motor pumps because the process liquid often provides bearing lubrication and removes motor heat. Running dry, inadequate venting or operating far outside the confirmed duty point can quickly damage internal components.
Before Startup
- Confirm the pump and suction piping are filled with liquid.
- Vent trapped gas from the pump and relevant piping points.
- Verify suction and discharge valve positions according to the system procedure.
- Check that the power supply matches the motor voltage, phase and frequency.
- Confirm the pump will not run dry.
- Check that the process liquid is within the confirmed temperature and viscosity range.
- For heated or high-melting-point media, confirm the required preheating condition before startup.
Low-temperature and volatile liquids require particular attention to suction pressure, vapor pressure and NPSHA because flashing at the suction can cause unstable operation.
During Startup
Start the pump according to the approved system procedure and confirm that flow and pressure develop normally. Observe the motor current, discharge pressure and any abnormal sound or vibration. If the pump does not build pressure, repeatedly loses suction or shows abnormal current, stop and investigate rather than allowing extended operation in an abnormal condition.
During Normal Operation
- Keep the pump within the confirmed operating range.
- Monitor suction and discharge pressure.
- Watch motor current for unexpected changes.
- Check for abnormal noise or vibration.
- Maintain any required heating, cooling or circulation arrangement.
- For pumps fitted with a TRG monitoring device, review the indication according to the applicable pump configuration and maintenance procedure.
Stable operation near the selected duty point is preferable to long-term operation at extreme low or high flow. Review the pump performance curve when comparing the actual operating point with the selected model.
Common Conditions to Avoid
- Dry running
- Insufficient suction pressure or cavitation
- Blocked internal circulation passages
- Unexpected solids larger than the confirmed particle limit
- Operation far outside the pump curve
- Incorrect voltage or frequency
- Rapid temperature change beyond the application design
Shutdown
Follow the plant shutdown sequence and isolate the pump safely. For fluids that may crystallize, freeze or solidify, the pump and piping may require draining, flushing or temperature maintenance after shutdown. Hazardous fluids must be handled according to the plant’s safety procedure before any maintenance work begins.
Maintenance Checks
If performance changes, motor current rises, or abnormal vibration appears, inspect the hydraulic and internal wear components. Bearings, shaft sleeves, thrust disks, thrust collars and the rotor assembly should be evaluated against the original dimensions and service conditions.
Replacement components are available through our Canned Motor Pump Spare Parts section.