- 20 -
- 20 -
Troubles
Symptom
Cause
Points to be checked
&
Countermeasures
When discharge
valve is closed.
When discharge
valve is opened.
Discharge
capacity is
too low.
Pressure & vacuum
are normal.
Pressure is high but
vacuum is normal.
• Actual head is too
high or pipe resist-
ance 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 wir-
ing.
• Power voltage is
low.
• Check voltage or fre-
quency.
• Overload
• Check specific gravity
and viscosity of liquid.
• Ambient tempera-
ture is too high.
• Keep a good ventilation.
Discharge
capacity is
rapidly re-
duced.
Vacuum gauge indi-
cates high figure.
• Suction piping
clogs with foreign
matters.
• Remove foreign matters.
• Poor foundation
• Reinstall the pump.
• Loose mounting
bolts.
• Retighten the bolts.
• Cavitation occurs.
• Remove the cause of
cavitation.
• The bearing is worn
or melted.
• Replace as necessary.
• Motor bearing is
worn.
• Replace bearing or
motor.
Motor is
overheated.
Pump
vibrates.
• Magnet capsule or
spindle is broken.
• Replace as necessary.
• Dynamic balance
of drive magnet is
upset.
• Remove the cause.
Replace as necessary.
Maintenance
