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50
PI Operation Manual
9. SECTION NINE - TROUBLESHOOTING CHART
TROUBLE
PROBABLE CAUSES
SUGGESTED SOLUTION
PUMP DOES NOT
DELIVER LIQUID
a. Inner pump parts are worn.
b. Density or viscosity of
pumped fluid is not same as
designed.
c. The motor voltage is
incorrect.
d. Motor runs only in two phase
mode.
e. Pump not primed.
f. Speed too low.
g. Feed pipe or impeller
plugged.
h. Clogged suction.
i. Damaged impeller.
j. Wrong rotation.
k. Pump or piping are not
properly vented.
l. Formation of air pockets in
the piping.
m. The counter pressure of
the system is greater than the
design point of the pump.
n. NPSHa too low.
a. Change worn parts.
b. Consult a WDM Pumps dealer.
c. Apply correct voltage to the motor.
d. Check the cables, connections and
fuses.
e. Prime pump.
f. Check driver input.
g. Clean pipe and impeller.
h. Clean out suction line.
i. Replace impeller.
j. Check driver rotation.
k. Vent or top up.
l. Install vent valve or lay piping
elsewhere.
m. Open discharge valve as wide
as necessary to reach the operating
point.
n. 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.