Installation and electrical connection en-US
Installation and operating instructions Wilo-Rexa UNI 17
▪The minimal permissible water level must not be un-
dercut!
▪The maximum switching frequency must not be ex-
ceeded!
▪For strongly fluctuating fluid levels, a level control de-
vice with two measuring points is recommended. This
means larger differential gaps are reached.
Use of the attached float switch
The A version is fitted with a float switch. The pump is
switched on and off depending on the fluid level. The
switching level is determined by the cable length on
the float switch.
Use of level control devices provided by the cus-
tomer
When using a level control device provided by the cus-
tomer, refer to the installation information in the man-
ufacturer’s 'Installation and operating instructions'.
6.4.7 Dry-running protection
Dry-running protection must prevent the pump from
being operated without fluid and air from penetrating
into the hydraulics. To do this the minimum permissible
fluid level must be determined using a signal transmit-
ter. As soon as the given limit value is reached, the
pump must be deactivated with a corresponding signal.
Dry-running protection can expand existing level con-
trol devices by an additional measuring point or work as
a sole switch-off device. The reactivation of the pump
can take place automatically or manually depending on
the system security. For optimum operational reliabil-
ity, the installation of a dry-running protection system
is recommended.
6.5 Electrical connection
DANGER
Electrocution hazard!
Improper conduct when carrying out electrical work
causes death due to electric shock! Electrical work
must be carried out by a qualified electrician in ac-
cordance with the local regulations.
▪The mains connection must match the specifications
on the rating plate.
▪Power supply on the mains side for three-phase current
motors with clockwise rotating field.
▪Route the power supply cable properly according to the
local regulations and connect in accordance with the
wire allocation.
▪Connect monitoring devices and check function.
▪Carry out earthing properly according to the local regu-
lations.
6.5.1 Line-side fuse protection
Circuit breaker
The size of the circuit breaker corresponds to the rated
current of the pump. The shifting characteristics should
correspond to group B or C. Observe the locally applica-
ble regulations.
Motor protection switch
For products without a plug provided by the customer,
a motor protection switch must be provided on-site!
The minimum requirement is a thermal relay/motor
protection switch with temperature compensation, dif-
ferential triggering and an anti-reactivation device, in
accordance with local regulations. Further protection
devices (e.g. overvoltage-, undervoltage- or phase fail-
ure relay etc.) must be provided on-site for sensitive
power supplies.
Residual-current device (RCD)
Adhere to the regulations of the local energy supply
company! We recommend using a residual-current de-
vice (RCD).
If persons come into contact with the product and con-
ductive liquids, secure connection with a residual-cur-
rent device (RCD).
6.5.2 Maintenance work
Before installation carry out the following maintenance
work:
▪Check insulation resistance of the motor winding.
▪Check resistor in the temperature sensor.
If the values measured deviate from the specifications,
moisture may have penetrated into the motor or the
power supply cable or the monitoring device may be
defective. In case of failure contact customer service.
6.5.2.1 Checking insulation resistance of the motor winding
Measure insulation resistance with an insulation tester
(measuring voltage = 1000V). Adhere to the following
values:
▪On initial commissioning: insulation resistance may not
be less than 20MΩ.
▪For further measurements: value must be larger than
2MΩ.
NOTICE!For motors with an integrated capacitor,
short circuit the windings before checking!
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