Wilo Rexa PRO Serie Instrucciones De Instalación Y Funcionamiento página 40

en-US
9.5.5.3 Testing the resistor of the exter-
nal electrode for sealing chamber
control
9.5.6 Oil change in sealing chamber
Fig. 15: Sealing chamber: Oil change
40
Maintenance and repair
▪ 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!
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.
+/- Fill/drain the oil in the sealing chamber
‡
Protective equipment has been put on!
‡
Pump is removed and cleaned (if necessary decontaminated).
1. Lay the pump horizontally on a firm surface. The screw plug is facing upwards. WARN-
ING! Danger of crushing hands. Make sure that the pump cannot fall over or slip!
+/-
2. Unscrew screw plug slowly but not fully. WARNING! Overpressure in the motor! If you
hear hissing or whistling sounds, do not turn any further! Wait until the pressure has
fully dissipated.
3. Once the pressure has fully dissipated, fully unscrew screw plugs.
4. Place a suitable tank to collect the operating fluid.
5. Drain operating fluid: Rotate the pump until the hole points downwards.
6. Check operating fluid: If there are metal filings in the operating fluid, inform customer
service!
7. Pour in operating fluid: Rotate the pump until the hole points upwards. Pour operating
fluid into the hole.
⇒ Adhere to the information for operating fluid type and quantity!
8. Clean the screw plug, replace the seal ring, and screw it back in. Max. tightening
torque: 8 Nm (5.9 ft lb)!
WILO SE 2019-02