Level Control; Dry-Running Protection - Wilo Rexa PRO Notice De Montage Et De Mise En Service

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Fig. 7: Dry well installation
6.4.6

Level control

6.4.7

Dry-running protection

Installation and operating instructions Wilo-Rexa PRO
Installation and electrical connection
▪ Connect the pump to the pipe system ensuring that it is free of stress and vibrations.
The use of elastic connection pieces (compensators) is recommended.
▪ The pump is not self-priming, in other words, the fluid must flow in either automatically
or with supply pressure. The minimum level in the collecting space must be at the same
height as the upper edge of the hydraulics housing!
▪ Max. ambient temperature: 40 °C (104 °F)
CAUTION! In dry well installation, comply with the operating mode "non-im-
mersed" (S1, S2-30, S3 25 %)! If "non-immersed" operating mode is not specified,
dry well installation is not possible!
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Machine room/installation location is prepared for the installation.
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Pipe system has been properly installed and is self-supporting.
1. Use a shackle to attach the lifting equipment to the attachment point of the pump.
2. Lift the pump and position it in the machine room.CAUTION! Hold the power sup-
ply cables slightly taut when positioning the pump!
3. Fasten pump to the foundation properly.
4. Connect pump to the pipe system. NOTICE! Ensure the connection is free of
stress and vibrations. If required, use plastic connection pieces (compensators).
5. Loosen the lifting gear from the pump.
6. Have the power supply cables installed in the machine room by a qualified electri-
cian.
▶ The pump is installed, the qualified electrician can make the electrical connection.
DANGER
Risk of explosion due to incorrect installation!
If the level control is installed within a potentially explosive area, the signal trans-
mitter must be connected via an Ex cut-off relay or a Zener barrier. There is a risk of
explosion if connected incorrectly! Connection must be carried out by a qualified
electrician.
With a level control device, the current fill levels are determined and the pump is
switched on and off automatically depending on the fill levels. Fill levels are recorded by
using different sensor types (float switches, pressure and ultrasound measurements or
electrodes). The following must be observed when using a level control device:
▪ Float switches can move freely!
▪ The water level must not fall below the minimum permissible!
▪ The maximum switching frequency must not be exceeded!
▪ If the fill levels fluctuate strongly, a level control with two measuring points is recom-
mended. This makes it possible to achieve larger differential gaps.
Dry-running protection must prevent the pump from operating without fluid and air
from entering the hydraulics. The minimum permissible fill level must be determined
with the help of a signal transmitter. Once the specified limit value is reached, the pump
must be deactivated with an appropriate signal. Dry-running protection can expand the
available level controls by an additional measuring point or function as an independent
switch-off device. Depending on the system security, the pump can be restarted auto-
matically or manually. Installation of dry-running protection is recommended for op-
timum operational reliability.
Pressure pipe
Gate valve for pressure pipe
Non-return valve
Compensator
Gate valve inlet
Inlet pipe
Level measurement of collecting space
Collecting space
Machine room
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