IWAKI PUMPS MXM Series, Instruction Manual

Page: 26 / 44

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Maintenance
1. Troubleshooting
Turn off power to stop operation upon sensing abnormalities. And then look for a root cause or
contact us as necessary.
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
pressure/vacuum
gauges drop to
zero.
• Priming liquid level is
too low.
• Dry running
• Stop and prime the
pump and resume
operation.
• Dismantle and inspect
the pump.
The pump can not
be primed.
• The foot valve malfunc-
tion due to foreign mat-
ter clogging.
• Clean the foot valve.
After starting, the
pressure drops as
a discharge valve
is opened.
The readings of
pressure/vacuum
gauges fluctuate
and drops to zero.
• Air ingress through a
suction line or a con-
nection.
• Check if suction line
connections are com-
pletely sealed.
• Check if liquid level in
supply tank is not too
low.
• Disconnection of the
magnet coupling
• Check if the motor
is not overloaded by
checking amperage.
• Check if foreign mat-
ters do not lock the
impeller or magnet
capsule.
• Check if voltage is nor-
mal.
The pressure
gauge keeps show-
ing a low pressure.
• Low pump speed
• The pump rotates in
reverse.
• Check wiring or motor.
• Interchange motor wir-
ing.
Discharge
capacity is too
low.
Pressure & vacu-
um are normal.
Vacuum is high.
• The strainer is clogged
with foreign matters.
• Remove foreign mat-
ters.
Vacuum is very
high.
• Air pocket in suction
line
• Check and correct suc-
tion line.
• Foreign matters are
clogged at impeller
inlet.
• Remove foreign mat-
ters.
The readings of
pressure gauge
& vacuum gauge
fluctuate.
• Air ingress from a suc-
tion line or a connec-
tion.
• Check suction line con-
nections and retighten
as necessary.
• The pump or discharge
line clogs with foreign
matters.
• Remove foreign mat-
ters or scales.
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 delivery head is
too high or pipe resist-
ance is too large.
• Check actual delivery
head and pipe resist-
ance.
Pressure is low
and vacuum is
very low.
Both pressure and
vacuum are low.
• The motor rotates in
reverse.
• Interchange motor wir-
ing.