Operating Faults And Their Possible Causes - Pratissoli MK29M Serie Manual De Uso Y Mantenimiento

a) The pump is used for purposes other than the agreed
purposes.
b) The pump is driven by an electric motor or internal
combustion engine having performance values exceeding
those shown in the table.
c) The safety devices provided are uncalibrated or
disconnected.
d) The pump has been used with accessories or spare parts
not supplied by Interpump Group.
e) Damage has been caused by:
1) improper use
2) failure to follow maintenance instructions
3) any use different from that described in the operating
instructions
4) lack of sufficient flow rate (suction)
5) defective installation
6) improper positioning or sizing of pipes
7) unauthorized design modifications
8) cavitation.
15 OPERATING FAULTS AND THEIR
POSSIBLE CAUSES
The pump does not prime upon start-up:
- The pump is not primed and is running dry, rpm
too high - see graph in par. 9.8.
- No suction bentonite.
- Valves are jammed.
- Outlet line is closed and thus prevents the
release of air trapped in the pump manifold.
Pump pulsates irregularly:
- Air suction.
- Insufficient supply.
- Bends, elbow bends, fittings along the suction
line are choking the passage of liquid.
- The pump is not primed for insufficient head.
- The pump is not primed due to valve jamming.
- Worn valves.
- Worn pressure seals.
- Imperfect functioning of the pressure control
valve.
- Problems on the transmission.
The pump does not supply the nominal flow rate/
excessive noise:
- Insufficient supply (see various causes as above).
- Rpm lower than the nominal speed;
- Excessive internal leakage of the 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 pump rpm.
- 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 the pressure control valve.
- Valves malfunction.
- Irregular drive transmission.
26