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QIS SERIES-M
03
OPERATION AND MAINTENANCE MANUAL
QIS SERIES
Centrifugal Pump
QUICK GUIDE FOR SOLVING COMMON PROBLEMS
Q-Pumps products are relatively easy to maintain with the exception of the sanitary process. Just
as with any other element of machining, problems may arise. This section offers a guide for
identifying and correcting most of the pumping problems. For problems with you motor, contact
the manufacturer directly for best assistance.
The following table illustrates the problems and probable causes, assuming that the pump was
correctly selected for a specific application. If none of the listed solutions provided in the table
resolves the problem, the most likely cause is cavitation. Cavitation may be caused by an incorrect
pump selection and its symptoms include: excessive noise, insufficient pressure, fluid leak and
vibration. If these symptoms are present, please re-evaluate your application.
1. NO FLOW
a) Motor speed too low.
b) Incorrect rotation direction.
c) Obstruction in discharge piping or
closed valves.
SOLUTIONS
a) Check electric connections and motor.
b) Reverse one of the motors three phases. If
direction does not change, contact manufacturer.
c) Remove obstruction and open valves.
2. INSUFICIENT FLOW
a) Motor speed too low.
b) Incorrect rotation direction.
c) Obstruction in discharge piping or closed valves.
d) Impeller damaged
a) Check electric connections and motor.
b) Reverse one of the motors three phases. If
direction does not change, contact manufacturer.
c) Remove obstruction and open valves.
d) Replace impeller
3. EXCESSIVE POWER CONSUMPTION
a) Motor speed too high.
b) Impeller damaged.
c) Motor shaft is bended or worn.
a) Motor wires are bad, replace motor.
b) Remove casing and replace impeller.
c) Replace motor shaft.
4. EXCESSIVE NOISE
a) Magnetic problem with motor.
b) Motor bearings damaged.
c) Foreign particles in impeller.
d) Impeller damaged.
e) Cavitation.
a) Consult motor manufacturer.
b) Replace bearings.
c) Remove casing and extract particles.
d) Replace impeller.
e) Check system’s available NPSH.
d) Cavitation.
5. EXCESSIVE VIBRATION
a) Pump is not leveled.
b) Impeller damaged.
c) Piping lacks supports.
d) Cavitation.
a) Level the pump.
b) Replace impeller.
c) Support suction and discharge piping.
d) Check system’s available NPSH.
6. FLUID LEAK
a) Disposable o-rings.
b) Disposable carbons.
c) Insufficient seal compression.
d) Damaged casing suction/discharge.
e) Disposable casing gasket.
f) Loose clamp assembly.
a) Replace o-rings.
b) Replace carbons.
c) Replace spring.
d) Replace casing.
e) Replace casing gasket.
f) Tighten clamp assembly.
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