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1. Troubleshooting
If you can not find out the root cause of failure, contact us.
Troubles
Symptom
Cause
Point to be checked
&
Countermeasures
When a discharge
valve is closed.
When a discharge
valve is opened.
Liquid can not
be discharged.
The readings of pres-
sure/vacuum gauges
drop to zero.
• Priming liquid level is too
low.
• Dry running
• Stop and prime the pump
and resume operation.
The pump can not be
primed.
• A foot valve doesn't close
due to foreign matter clog-
ging.
• Clean the foot valve and a
seat.
After starting, pres-
sure drops sharply as
a discharge valve is
opened.
The readings of pres-
sure/vacuum gauges
fluctuate and drop to
zero.
• Air ingress through a suc-
tion line or a sealing sur-
face.
• Check if suction line con-
nections are completely
sealed.
• Check if liquid level in
supply tank is not too low.
• A disconnection of the
magnet coupling
• Check amperage to see if
the motor is not overload-
ed.
• Check if foreign matters
do not lock the impeller or
magnet capsule.
• Check if voltage is normal.
Discharge pressure
does not rise.
• Low pump speed
• The pump rotates in
reverse.
• Check wiring or motor.
• Correct wiring.
Discharge
capacity is too
low.
Pressure & vacuum
are normal.
Vacuum is high.
• The strainer is clogged
with foreign matters.
• Remove foreign matters.
Vacuum is very high.
• Air pocket in suction line • Check and correct suction
line.
• Foreign matters are
clogged at impeller inlet.
• Remove foreign matters.
The readings of pres-
sure gauge & vacu-
um gauge fluctuate.
• Air ingress from a suction
line or a sealing surface.
• Check suction line con-
nections and retighten as
necessary.
• Discharge line clogs with
foreign matters.
• Remove foreign matters or
scale from pump/piping.
Vacuum is high but
pressure is normal.
• Resistance such as air
pocket in suction line.
• Check if there is no
arched pipework.
Vacuum is normal
but pressure is high.
• Actual head is too high or
pipe resistance is too large.
• Check actual head and
pipe resistance.
Pressure is low and
vacuum is very low.
Pressure and vacu-
um are low.
• Motor rotates in reverse. • Interchange motor wiring.
Motor is over-
heated.
• Power voltage is low.
• Overload
• Check voltage or frequency.
• Check specific gravity and
viscosity of liquid.
• Keep good ventilation.
Discharge
capacity is rap-
idly reduced.
Vacuum is high.
• A suction line clogs with
foreign matters.
• Remove foreign matters.
Pump vibrates.
• Poor foundation
• Loose mounting bolts.
• Cavitation occurs.
• Pump bearing is worn or
melted.
• Magnet capsule or spindle
is broken.
• Dynamic balance of drive
magnet is upset.
• The rotating part hits
against other parts.
• Motor bearing is worn.
• Reinstall the pump.
• Retighten the bolts.
• Remove the cause of
cavitation.
• Replace as necessary.
• Replace as necessary.
• Remove the cause.
Replace as necessary.
• Replace as necessary.
• Replace bearing or motor.
Maintenance
