en
Maintenance and repair
36
WILO SE 2017-12
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 temperat-
ure 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.
WARNING
Scalding due to hot operating fluids!
Hot operating fluids can also spray out when the pressure is escaping. This can result
in scalding! To avoid injuries, the following instructions must be observed:
• Allow the pump to cool down to the ambient temperature then open the screw
plugs.
• Wear closed safety goggles or face protection and gloves.
