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8
Problem
Cause
What to do
Wrong direction of
rotation
Electric cables to motor wrongly con
nected.
Reverse the terminal connection on electric
motor.
17
Connecting and disconnecting
of electric cables must be
done only by personnel
authorized to do such work.
The pump cannot be
primed
Wrong direction of rotation.
See above.
Suction line is not open or pressure
drop in the suction line is too high.
Check all components in suction line. The
inlet condition should be checked with a
vacuum gauge at the pump inlet.
Check oil viscosity.
Major air leakage into the suction line.
Check the suction line.
The pump cannot evacuate the air
through the discharge line due to
excessive counter pressure.
See the chapter on Deaeration (page 4).
No flow
The pump is not primed.
See above.
The pressure relief valve is set be
low the counter pressure or outlet is
blocked.
Check outlet line. Readjust the pressure
relief valve to a value above counter pres
sure.
Flow too low
The pressure relief valve is set too low
(Discharge pressure also low).
Readjust the pressure relief valve
- Something is restricting the flow in the
suction line. (This would usually cause
noise).
Check all components in the suction line
(strainers, valves etc.).
The pumped liquid contains a sig
nificant amount of compressible gas,
such as free air. (This would usually
cause noise).
See next page, Noise and Vibration
(page 9).
Pressure too low
The pressure relief valve is set too
low.
Readjust the pressure relief valve.
Counter pressure in the discharge line
is too low due to a major leakage.
Check the components in the discharge
line inclusive the recipients.
The valve piston is stuck in open posi
tion.
Check the valve. See Installation & Ser
vice instruction for respective pump.
- Something is restricting the flow in the
suction line. (This would usually cause
noise).
Check all components in the suction line
(strainers, valves etc.).
The pumped liquid contains a sig
nificant amount of compressible gas,
such as free air. (This would usually
cause noise).
See next page, Noise and Vibration
(page 9).
A too small pump has been chosen.
Contact your IMO AB representative.
Trouble shooting
