Troubleshooting - Lowara e-SV Series Installation And Operation Instructions Manual

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10. Troubleshooting

PROBLEM
The electric pump unit
does not start.
The main switch is on
The electric pump unit
starts up but the thermal
protector is immediately
triggered or the fuses
blow
The electric pump unit
starts up but, after a short
time, the thermal
protector is triggered or
the fuses blow
The electric pump unit
starts up but, after a
varying period of time, the
thermal protector is
triggered
The electric pump unit
starts up but does not
deliver the required flow
The system's general
protection cuts in
The system's differential
thermal-magnetic
protection cuts in
The pump rotates in the
wrong direction when it is
stopped
The pump starts up too
frequently
The pump vibrates and
generates too much noise
22
PROBABLE CAUSE
No power supply
Triggering of thermal protector incorporated in the
pump (if any)
Triggering of thermal relay or motor protector
found
in the electric control panel
Pump or auxiliary circuits protection fuses blown
Triggering of protection device against dry running
Power supply cable is damaged
Electric motor short circuit
Thermal protector or fuses not suited to the motor
current
Motor overload
A phase in the power supply is missing
Power supply voltage not within the motor's
working limits
The electric panel is situated in an excessively
heated area or is exposed to direct sunlight
There are foreign bodies inside the pump, the
impellers are jammed
The pump's delivery rate is higher than the limit
specified on the rating plate
The pump is overloaded because it is sucking a
dense and viscous liquid
Worn motor bearings
Wrong rotation direction (three-phase version)
Pump is not primed because not filled with water
Pump not primed due to tightness failure in
suction pipe or foot valve
Air in the pipes or pump
Excessive suction lift or flow resistance in suction
piping
Piping or pump clogged
Valves locked in closed or partially closed position
Short circuit
Ground leakage
Leaks in suction pipe
Leaks in foot valve or check valve
Air in the suction pipe
Leaks in foot valve, check valve or system
Ruptured membrane or no air pre-charge in surge
tank
Pump cavitation
Worn motor bearings
Presence of foreign bodies inside the pump,
between the impellers and diffusers
information for users and maintenance personnel
POSSIBLE SOLUTION
Restore the power supply
Wait for the pump motor to cool down
Reset the thermal protector
Replace fuses
Check the water level in the tank or the mains
pressure. If everything is in order, check the
protection device and its connection cables
Check the components and replace as necessary
Check the operating conditions of the electric pump
unit and reset the protection
Check the power supply
Check the operating conditions of the electric pump
unit
Protect the panel from heat sources and from the
sun
Disassemble and clean the pump
Partially close the on-off valve located downstream
until the delivery rate returns within the specified
limits
Check the actual power requirements based on the
characteristics of the pumped liquid, and replace the
motor accordingly
Replace the bearings or the motor
Check the direction of rotation and, if necessary,
exchange two phases in the motor or in the electrical
panel
Repeat the priming procedure and make sure there
are no leaks in the mechanical seal
Check the suction pipe and foot valve for perfect
tightness, make sure there are no leaks in the
mechanical seal
Bleed the air
Check the operating conditions of the pump. If
necessary, decrease suction lift and/or increase the
diameter of the suction pipe
Disassemble and clean
Disassemble and clean, if necessary replace the valve.
Check electrical system
Check insulation of the electrical system components.
Check and locate leaks
Repair or replace components.
Bleed the air
Check and locate leaks. Repair or replace the
components.
See relevant instructions in surge tank manual
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,....)
Replace bearings or motor
Disassemble and clean the pump