Maintenance and repair
en
Installation and operating instructions Wilo-EMU TR/TRE 50-2 ... 120-1
35
If damage to the connection cable is identified, decommission the mixer immediately!
Have the connection cable replaced by Wilo customer service. Only start the mixer up
again once the damage has been properly remedied!
CAUTION! Water can enter into the mixer if the connection cable is damaged! Water
ingress leads to the mixer being written off.
9.5.3
Visual inspection of cable brack-
ets and cable tensioning
Check cable brackets and anchoring of the connection cable (lifting equipment or sep-
arate nylon rope) for material fatigue or shrinkage. If there are signs of wear, replace the
faulty components immediately.
9.5.4
Visual inspection for wear of the
mixer
Inspect individual components (propeller, hub, etc.) for damage and wear. If there are
defects, 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!
9.5.5
Function test of the monitoring
device
The mixer must be cooled down to ambient temperature to test resistances!
9.5.5.1
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:
ƒ
Bimetallic strip
: Measured value = 0 Ohm (passage).
ƒ
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.
9.5.5.2
Check the resistance of the ex-
ternal electrode for pre-chamber
monitoring
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
Visual inspection of accessories
Accessories must be checked for:
ƒ
Correct fixation
ƒ
Smooth function
ƒ
Signs of wear, e.g. cracks caused by frequencies
Any defects detected must be repaired immediately or the accessories must be re-
placed.
9.5.7
Oil change
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 from hot operating fluids!
Hot operating fluids can also spray out when pressure is released. This can result in
scalding! To avoid injuries, the following instructions must be observed:
• Allow the motor to cool down to the ambient temperature before opening the
screw plugs.
• Wear closed safety goggles or face protection and gloves.
