21
n
Trouble
Inspection and
Countermeasures
With Discharge
Valve Closed
With Discharge
Valve Open
Cause
Needle of
pressure gauge
indicates low
value and
vacuum gauge
indicates
extraordinarily
low value.
Needle of
pressure gauge
and vacuum
gauge indicate
low value.
l
Rotating direction
of pump/motor is
reversed.
¡
Correct motor wiring to
reverse rotation. (Clock-
wise when viewed from
motor side.)
¡
Check whether voltage
and frequency levels are
adequate.
l
Overload.
¡
Check whether specific
gravity and viscosity of
liquid are above specifi-
cation.
¡
Stop pump and use
screwdriver, etc., to
check whether motor fan
rotates easily and
smoothly.
l
Ambient tempera-
ture is high.
¡
Improve air ventilation.
Discharge
quantity is
suddenly
lowered.
l
Strainer is clogged
with foreign matter.
¡
Remove foreign matter.
Motor
overheats
Discharge
quantity is
too low.
Needle of
vacuum gauge
indicates high
value.
l
Voltage is insufficient
