English
Installation and operating instructions Wilo-Sub TWU4
13
• Provide an earth.
• Motor protection is provided by a thermal or mag-
netic switch (exists in the case of the EM version,
needs to be provided for the DM version)
8 Commissioning
8.1 Checking the direction of rotation (for three-
phase motors only. The direction of rotation
cannot be confused in the case of AC motors)
To determine the correct direction of rotation, it is
sufficient to check the water pressure on the
pressure side of the pump when it is switched on.
NOTE: If the pump is operated in the wrong direc-
tion of rotation, the flow volume is reduced.
If the direction of operation is incorrect, 2 phases
of the mains connection (in the switchbox or at
the contact maker) have to be changed over.
8.2 Commissioning
CAUTION! Risk of damage!
Risk of damage of the mechanical seal. Never
allow the pump to run dry, even for a short time!
• Check all the electrical connections, the electrical
protection and also the fuses once more.
• Check the current consumption phase by phase
and compare with the values on the name plate.
Never exceed the motor nominal current (In)
permitted for the motor (see name plate).
• Check the voltage with the motor running.
Permitted tolerance: +/- 10%.
• Vent the pressure port to avoid pressure surges
when starting.
• The slide valves on the pressure side must be half
open for the first commissioning so that the pipe
can be vented.
• Never operate the pump for more than 2 minutes
with the valve closed.
8.3 Medium temperature
At nominal current, submersible pumps may be
operated between a minimum temperature of 3°C
and a maximum temperature of 30°C.To guaran-
tee cooling of the motor at higher temperatures,
the flow rate must be reduced proportionally to
the motor power (see following table).
NOTE:Do not operate the motors at medium tem-
peratures that exceed 55°C!
9 Maintenance
Maintenance and repair work to be done by
qualified personnel only!
DANGER! Mortal danger
There is a risk of a fatal shock when working on
electrical equipment.
• For all maintenance and repair work, the pump
must be switched off and prevented from being
switched on again accidentally.
• Damage to connecting cables may only be
repaired by a qualified electrical contractor in
principle.
NOTE: No special maintenance is necessary during
normal operation.
Medium temperature
Water
temperatur
e
Adjustment (%) of the nominal
current from 0.37 kW to 5.5 kW
35°C
95 %
40°C
95%
45°C
90%
50°C
80%
55°C
70%
