English
Installation and operating instructions Wilo-Sub TWI4-6
9
10 Faults, causes and remedies
Only have faults remedied by qualified personnel!
Follow the safety instructions in Maintenance.
If the operating fault cannot be remedied,
please consult a skilled professionals or the
nearest Wilo after-sales service or representa-
tive office.
11 Spare parts
Spare parts may be ordered via local professional
technicians and/or the Wilo after-sales service.
To avoid queries and incorrect orders, all data on
the name plate should be submitted for each
order.
Subject to change without prior notice!
Faults
Causes
Remedy
Pump does not start.
Incorrect voltage or voltage drop.
Check voltage during start, a too narrow a
cable cross-section can lead to a voltage
drop and the pump does not start.
Breaks in the connecting cable.
Measure the phase resistances, pull up the
pump and check the cable.
The motor protection switch has been
triggered.
Check the protective switch setting of the
triggering current strength and compare it
with the nominal current being drawn.
The pump starts too often.
Reduce the number of starting procedures,
danger of motor overheating
(approx. 1 min.).
Pump running but does
not pump.
No water or the water level is too low
• Check the water level, ensure there is
min. 0.20 m water above the suction port.
• Vent pump.
The volume flow is too low.
The suction filter is blocked
Pull up the pump and clean the filter.
Incorrect direction of rotation (DM version)
Change two phases in the connection box.
The pump starts too often.
The difference between the switch-on and
switch-off pressure too low
Increase the difference between the
switch-on and switch-off pressure.
Electrodes are installed incorrectly.
Arrange the electrodes at a distance from
each other so adequate time between pump
standstill and pump operation is guaran-
teed.
The diaphragm expansion tank is too small
or has incorrect supply pressure.
Check and regulate the pressure (switch on
and off). Check the tank supply pressure.
Replace the diaphragm expansion tank with
a larger one or supplement with an addi-
tional diaphragm expansion tank.
