Wilo Rexa CUT GE, Installation And Operating Instructions Manual

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en Maintenance and repair
156 WILO SE 2019-02
motor, which can be rectified. Larger voltage fluctuations strain the motor winding and
can cause the pump to break down. Regular inspections can therefore largely prevent
major secondary damage and reduce the risk of total breakdown. In this regard, it is re-
commended to use remote monitoring for regular inspections.
9.5.2 Visual inspection of the connec-
tion cable
Check connection cable for:
▪ Bubbles
▪ Cracks
▪ Scratches
▪ Abrasion
▪ Pinch points
If damage is identified on the connection cable, decommission the pump immediately!
Have the connection cable replaced by Wilo customer service. Only operate the pump
up again once the damage has been properly remedied!
CAUTION! Water may penetrate into the pump due to the damaged connection
cable! Water ingress leads to total failure of the pump.
9.5.3 Visual inspection of accessories
Accessories must be checked for:
▪ Correct fixation
▪ Smooth function
▪ Signs of wear, e.g. cracks caused by frequencies
Any defects detected must be repaired immediately or the accessories must be re-
placed.
9.5.4 Visual inspection of coatings and
housing for wear
The coatings and housing parts must not show any signs of damage. If there are de-
fects, the following must be observed:
▪ If the coating is damaged, it must be restored.
▪ Contact customer service if housing parts have worn out!
9.5.5 Function test of the monitoring
device
To test resistances, the pump must be cooled down to the ambient temperature!
9.5.5.1 Test the resistor of the internal
electrodes for motor compart-
ment monitoring
Measure the resistor of the electrode with an ohmmeter. The measured value must ap-
proach “infinity”. For values ≤ 30 kOhm, there is water in the motor compartment.
Con-
tact customer service!
9.5.5.2 Test the resistor of the temper-
ature sensor
Measure the resistor of the temperature sensors with an ohmmeter. The following
measured values must be complied with:
▪ Bimetallic strip : Measured value = 0 Ohm (passage).
▪ PTC sensor (PTC thermistor): Measured value depends on the number of sensors in-
stalled. At PTC sensor has a cold resistance of between 20 and 100 Ohm.
– With
three sensors in series, the measured value is between 60 und 300 Ohm.
– With four sensors in series, the measured value is between 80 und 400 Ohm.
9.5.5.3 Testing the resistor of the ex-
ternal electrode for sealing cham-
ber control
Measure the resistor of the electrode with an ohmmeter. The measured value must ap-
proach “infinity”. For values ≤ 30 kOhm, if there is water in the oil – change the oil!
9.5.6 Oil change in sealing chamber
WARNING
Operating fluid under high pressure!
A pressure of several bar can build up in the motor! This pressure escapes when the
screw plugs are opened . If screw plugs are opened without due caution, they can be
ejected at high speed! To avoid injuries, observe the following instructions:
• Adhere to the prescribed sequence of work steps.
• Unscrew the screw plugs slowly, but never unscrew them completely. As soon
as the pressure escapes (audible whistling or hissing of air), stop turning the
screw plug any further!
• When the pressure has completely dissipated, fully unscrew the screw plugs.
• Wear closed safety goggles.