Operation Manual

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8. Troubleshooting
Information for users and maintenance personnel
PROBLEM PROBABLE CAUSE POSSIBLE SOLUTION
No power supply Restore the power supply
Triggering of thermal protector incorporated in the pump (if
any)
Wait for the pump motor to cool down
Triggering of thermal relay or motor protector found in the
electric control panel
Reset the thermal protector
Pump or auxiliary circuits protection fuses blown Replace fuses
The electric pump does not start.
The main switch is on
Triggering of protection device against dry running
Check the water level in the tank or the water sys tem
pressure. If everything is in order, check the protection
device and its connection cables
Power supply cable is damaged
Electric motor short circuit
Thermal protector or fuses not suited to the motor current
Check the components and replace as necessary
The electric pump starts up but the thermal protector is
immediately triggered or the fuses blow
Motor overload
Check the operating conditions of the electric pump and
reset the protection
A phase in the power supply is missing Check the power supply
Power supply voltage not within the motor’s work- ing limits Check the operating conditions of the electric pump
The electric pump starts up but, after a short time, the
thermal protector is triggered or the fuses blow
The electric panel is situated in an excessively heat- ed
area or is exposed to direct sunlight
Protect the panel from heat sources and from the sun
There are foreign bodies inside the pump, the impellers are
jammed
Disassemble and clean the pump
The pump’s delivery rate is higher than the limit specified on
the rating plate
Partially close the on-off valve located downstream until the
delivery rate returns to within the specified limits
The pump is overloaded because it is sucking a dense and
viscous liquid
Check the actual power requirements based on the
characteristics of the pumped liquid, and replace the motor
accordingly
The electric pump starts up but, after a varying period
of time, the thermal protector is trig gered
Worn motor bearings Replace the bearings or the motor
Wrong rotation direction (three-phase version)
Check the direction of rotation and, if necessary, exchange
two phases in the motor or in the electri cal panel
Pump is not primed because not filled with water
Repeat the priming procedure and make sure there are no
leaks in the mechanical seal
Pump not primed due to tightness failure in suction pipe or
foot valve
Check the suction pipe and foot valve for perfect tightness,
make sure there are no leaks in the mechanical seal
Air in the pipes or pump Bleed the air
Excessive suction lift or flow resistance in suction piping
Check the operating conditions of the pump. If necessary,
decrease suction lift and/or increase the diameter of the
suction pipe
Piping or pump clogged Disassemble and clean
The electric pump starts up but does not deliv- er the
required flow
Valves locked in closed or partially closed position Disassemble and clean, if necessary replace the valve.
The system’s general protection cuts in Short circuit Check electrical system
The system’s differential thermal-magnetic protection
cuts in
Ground leakage Check insulation of the electrical system components
Leaks in suction pipe Check and locate leaks.
Leaks in foot valve or check valve Repair or replace the components.
The pump rotates in the wrong direction when it is
stopped
Air in the suction pipe Bleed the air
Leaks in foot valve, check valve or system Check and locate leaks. Repair or replace the components.
The pump starts up too frequently
Ruptured membrane or no air pre-charge in surge tank See relevant instructions in surge tank’s manual
Pump cavitation
Reduce the required flow rate by partially closing the on-off
valve downstream from the pump. If the problem persists
check the operating conditions of the pump (height
difference, flow resistance, liquid temperature,….)
Worn motor bearings Replace bearings or motor
The pump vibrates and generates too much noise
Presence of foreign bodies inside the pump, between the
impellers and diffusers
Disassemble and clean the pump
9. Disposal
Information for installation and maintenance personnel
Observe the regulations and codes locally in force regarding sorted waste disposal
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