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9
Problem
Cause
What to do
Wrong direction of rota-
tion
- Electric cables to motor wrongly
connected.
Reverse the terminal connection on
electric motor.
20
Connecting and disconnec-
ting of electric cables must
be done only by personnel
authorized to do such
work.
The pump cannot be
primed
- Wrong direction of rotation.
- Suction line is not open or pressure
drop in the suction line is too high.
- Major air leakage into the suction
line.
- The pump cannot evacuate the air
through the discharge line due to
excessive counter pressure.
See above.
Check all components in suction line.
The inlet condition should be checked
with a vacuum gauge at the pump inlet.
Check the suction line.
See the chapter on Deaeration
(see page 22).
No flow
- The pump is not primed.
- The pressure relief valve is set be-
low the counter pressure.
See above.
Readjust the pressure relief valve to a
value above counter pressure.
Flow too low
- The pressure relief valve is set too
low (Discharge pressure also low).
- Something is restricting the flow in
the suction line. (This would usually
cause noise).
- The pumped liquid contains a signif-
icant amount of compressible gas,
such as free air. (This would usually
cause noise).
Readjust the pressure relief valve
Check all components in the suction
line (strainers, valves etc.).
See the chapter on Noise and Vibra-
tion. ( Page 11).
Pressure too low
- The pressure relief valve is set too
low.
- Counter pressure in the discharge
line is too low due to a major leak-
age.
- The valve piston is stuck in open
position.
- Something is restricting the flow in
the suction line. (This would usually
cause noise).
- The pumped liquid contains a signif-
icant amount of compressible gas,
such as free air. (This would usually
cause noise).
- A too small pump has been chosen.
Readjust the pressure relief valve.
Check the components in the discharge
line inclusive the recipients.
Check the valve. See Maintenance and
Service instruction for respective pump.
Check all components in the suction
line (strainers, valves etc.).
See the chapter on Noise and Vibra-
tion. (Page 11).
Contact your IMO AB representative.
Trouble shooting
