Wilo Sub TWI 4 Serie Notice De Montage Et De Mise En Service page 41

Motor protection relays, overvoltage relays and other
tripping devices can generally be triggered manually for
test purposes.
9 Troubleshooting and possible solutions
In order to prevent damage or injury while rectifying
product faults, the following points must be observed
in all cases:
• Only attempt to rectify a fault if you have qualified
staff. This means that each job must be carried out by
trained specialist staff. For example, electrical work
must be performed by a trained electrician.
• Always secure the product against an accidental restart
by disconnecting it from the mains. Take appropriate
safety precautions.
• Always have a second person on hand to ensure that
the product has been switched off for safety.
• Secure moving parts to prevent injury.
• Unsanctioned changes to the product are made at the
operator's own risk and release the manufacturer from
any warranty obligations.
9.0.1 Fault: The unit will not start
1 Electricity supply interrupted, short circuit or earth
fault in the cable or motor windings
• Have the motor and wires checked by a specialist
and replaced if necessary.
2 Fuses, the motor protection switch and/or monitoring
devices are triggered
• Have a specialist inspect the connections and cor-
rect them as necessary.
• Have the motor protection switches and fuses
installed or adjusted according to the technical spec-
ifications, and reset monitoring equipment.
• Check that the impeller runs smoothly. Clean or free
it as necessary.
9.0.2 Fault: The unit starts, but the motor protection
switch triggers shortly after start-up
1 The thermal trigger on the motor protection switch is
incorrect/set incorrectly
• Have a specialist compare the selection and setting
of the trigger with the technical specifications and
correct if necessary
2 Increased power consumption due to major voltage
drop
• Have an electrician check the voltage on each phase
and rewire if necessary
3 Two-phase operation
• Have a specialist inspect the connection and correct
it as necessary
4 Excessive voltage differences on the three phases
• Have a specialist inspect the connection and the
switching system and correct if necessary
5 Incorrect direction of rotation
• Swap the 2 phases from the mains supply
6 Impeller impeded by adhesive material, blockages and/
or solid matter, increased current consumption
• Switch off the unit, secure it against being switched
on again and free the impeller or clean the intake
port
7 The pumped liquid is too dense
• Contact the manufacturer
Installation and operating instructions Wilo-Sub TWI 4..., TWI 4...-QC
9.0.3 Fault: Unit runs but does not pump
1 No pumped liquid
• Open the container intake or sliders
2 Intake blocked
• Clean the intake, slider, intake port or intake strainer
3 Impeller blocked or obstructed
• Switch off the unit, secure it against being switched
on again and free the impeller
4 Defective hose or pipeline
• Replace defective parts
5 Intermittent operation (cycles)
• Check the control panel
9.0.4 Fault: The unit runs, but not at the stated operating
levels
1 Intake blocked
• Clean the intake, slider, intake port or intake strainer
2 Slider in the discharge pipe closed
• Open the slider and constantly monitor the power
consumption
3 Impeller blocked or obstructed
• Switch off the unit, secure it against being switched
on again and free the impeller
4 Incorrect direction of rotation
• Replace two phases on the mains supply
5 Air in the system
• Check the pipelines, pressure shroud and/or hydrau-
lics, and bleed if necessary
6 Unit is pumping against excessive pressure
• Check the slider in the discharge pipe and open it
completely if necessary, use a different impeller or
contact the factory
7 Signs of wear
• Replace worn parts
• Check for solids in the pumped liquid
8 Defective hose or pipeline
• Replace defective parts
9 Inadmissible levels of gas in the pumped liquid
• Contact the factory
10 Two-phase operation
• Have a specialist inspect the connection and correct
it as necessary
11 Excessive decrease in the water table during operation
• Check the supply and capacity of the system, and
inspect the level control settings and functionality
9.0.5 Fault: The unit does not run smoothly and is noisy
1 Unit is running in an inadmissible operation range
• Check the operational data of the unit and correct if
necessary and/or adjust the operating conditions
2 The intake port, strainer and/or impeller is blocked
• Clean the intake port, strainer and/or impeller
3 The impeller is impeded
• Switch off the unit, secure it against being switched
on again and free the impeller
4 Inadmissible levels of gas in the pumped liquid
• Contact the factory
5 Two-phase operation
• Have a specialist inspect the connection and correct
it as necessary
6 Incorrect direction of rotation
• Replace two phases on the mains supply
7 Signs of wear
• Replace worn parts
8 Defective motor bearing
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