www.wdmpumps.com
51
PI Operation Manual
TROUBLE
PROBABLE CAUSES
SUGGESTED SOLUTION
CAPACITY OR
DISCHARGE
PRESSURE LOW
a. Air leaks into suction.
b. Speed too low.
c. Clogged suction.
d. Clogged impeller.
e. Damaged impeller.
f. Wrong rotation.
g. Feed pipe or impeller
plugged.
h. Formation of air pockets in
the piping.
i. Inner pump parts are worn.
j. Density or viscosity of
pumped fluid is not same as
designed.
k. The motor voltage is
incorrect.
l. Motor connected only in two-
phase mode.
m. NPSHa too low.
a. Check suction line for leaks.
b. Check driver and its power source.
c. Clean out suction line.
d. Clean impeller.
e. Replace impeller.
f. Check motor (driver) rotation.
g. Clean pipe and impeller.
h. Install vent valve or lay piping
elsewhere.
i. Change worn parts.
j. Consult a WDM Pumps dealer.
k. Apply correct voltage to the motor.
l. Check the cables, connections and
fuses.
m. Check the fluid level in the feed
container.
Open suction valve completely.
Lay suction pipe elsewhere as friction
losses are too great.
Check for a possible filter in the feed
pipe.
DRIVER
OVERLOAD
a. Density or viscosity of
pumped fluid is not same as
designed.
b. Speed too high.
c. Pump is under tension.
d. The motor voltage is
incorrect.
e. Motor connected only in two-
phase mode.
f. System head lower than
rating.
a. Consult a WDM Pumps dealer.
b. Decrease driver speed.
c. Check the piping for tension free
connections.
d. Apply correct voltage to the motor.
e. Check the cables, connections and
fuses.
f. Check suction and discharge
pressure.
