Pratissoli MF7M Serie Manual De Uso Y Mantenimiento página 28

The pump does not supply the nominal flow
rate/excessive noise:
- Insufficient supply (see various causes as above).
- Pump speed is below the rated speed;
- Excessive internal leakage of pressure control
valve.
- Worn valves.
- Excessive leakage from the pressure seals.
- Cavitation due to:
1) Improper sizing of suction ducts/undersized
diameters.
2) Insufficient flow rate.
3) High fluid temperature.
The pressure supplied by the pump is insufficient:
- Use is or has become higher than the capacity of
the pump.
- Insufficient revolutions per minute.
- Excessive leakage from the pressure seals.
- Imperfect functioning of the pressure control
valve.
- Worn valves.
Pump overheats:
- The pump is working in overpressure conditions
or pump rpm is higher than the nominal value.
- Oil in the pump casing is not at level or not the
recommended type as detailed in chapter 7 (see
par. 7.6).
- Joint or pulley alignment is incorrect.
- Excessive pump tilt during operation.
Vibrations or hammering on pipes:
- Air suction.
- Faulty operation of pressure control valve.
- Valves malfunction.
- Non-uniformity of transmission motion.
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