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9.5.3
Visual inspection of the cable
brackets and cable tensioning
9.5.4
Visual inspection for wear of the
mixer
9.5.5
Function test of the monitoring
devices
9.5.5.1
Checking resistor in the tempera-
ture sensor
9.5.5.2
Check the resistance of the exter-
nal electrode for pre-chamber
monitoring
9.5.6
Visual inspection of accessories
9.5.7
Oil change
38
Maintenance and repair
Check cable brackets and anchoring of the connection cable (lifting equipment or separate
nylon rope) for material fatigue or shrinkage. If there are signs of wear, replace the faulty
components immediately.
Inspect individual components (propeller, hub, etc.) for damage and wear. If there are de-
fects, observe the following:
ƒ
If the coating is damaged, restore it.
ƒ
If components have worn, contact customer service and replace the components in
question!
The mixer must be cooled down to ambient temperature to test resistances!
Check resistor in the temperature sensor with an ohmmeter. The following measured values
must be complied with:
ƒ
Bimetallic strip: Measured value = 0 Ohm (passage).
ƒ
PTC sensor (positive temperature coefficient thermistor): Measured value depends on
the number of sensors installed. A PTC sensor has a cold resistance of between 20 and
100 Ohm.
–
With three sensors in series, the measured value is between 60 and 300 Ohm.
–
With four sensors in series, the measured value is between 80 and 400 Ohm.
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 oil – change the oil!
The accessories must be checked for:
ƒ
Correct attachment
ƒ
Proper function
ƒ
Signs of wear, e.g. cracks caused by vibrations
Any detected defects must be repaired immediately or the accessories must be replaced.
WARNING
Operating fluid under high pressure!
A pressure of several bar can build up inside the motor! This pressure escapes when
opening the screw plugs. Screw plugs opened carelessly can be ejected at high speed! To
avoid injuries, observe the following instructions:
• Adhere to the prescribed sequence of work steps.
• Unscrew screw plugs slowly but never fully. As soon as the pressure escapes (audible
whistling or hissing of air), do not turn any further!
• When the pressure has fully dissipated, fully unscrew screw plugs.
• Wear closed safety goggles.
WARNING
Scalding due to hot operating fluids!
When the pressure escapes, hot operating fluid can also be ejected. This can result in
scalding! To avoid injuries, the following instructions must be observed:
• Allow the mixer to cool to ambient temperature, then open the screw plugs.
• Wear closed safety goggles or face protection as well as gloves.
WILO SE 2021-05