9Repair Thermo 90 S / Thermo 90 ST
904
9.2.3 Changing the temperature limiter
9.2.3.1 Removal
NOTE
The temperature limiter only has to be removed if it is
being replaced with a new one.
The function must be checked in the installed condition.
1. Remove the heater (see 8.7.1.1).
2. Disconnect the electrical connections (see 9.2.1.1).
3. Remove the clip (2, Fig. 903) and pull off the
protective cap (1).
4. Use a screwdriver to lever off the retaining spring and
remove the temperature limiter (3).
5. Complete the work on stripped-down components
(see 9.1.1).
NOTE
It is essential to fit a new temperature limiter to replace a
removed one!
9.2.3.2 Installation
CAUTION
Incorrect installation will cause the heat exchanger to
melt.
1. Insert the new temperature limiter (3, Fig. 903) into the
heat exchanger (4) and press in the retaining spring.
NOTE
You must be able to hear and feel the spring clip into
the groove. Only then is the temperature limiter in the
correct installation position.
If you do not hear and feel the spring clip in:
• Clean the contact surface of the temperature limiter
on the heat exchanger
• Clean the groove in the heat exchanger
• Ensure that the detent lugs are present on both sides
of the spring. Fit a new temperature limiter if
necessary.
2. Put on the protective cap (1) and secure it with the
clip (2).
3. Tighten the clip to 1 Nm ±10%.
4. Connect the electrical connections (see 9.2.1.2).
5. Install the heater (see 8.7.1.2).
9.2.4 Changing the temperature sensor
9.2.4.1 Removal
1. Remove the heater (see 8.7.1.1).
2. Disconnect the electrical connections (see 9.2.1.1).
WARNING
Leaking hot coolant can cause burns.
3. Unscrew and remove the temperature sensor
(6, Fig. 903) and remove it together with the round
sealing ring (5).
4. Complete the work on stripped-down components
(see 9.1.1).
9.2.4.2 Installation
1. Apply acid-free grease (Vaseline) to the round sealing
ring (5, Fig. 904).
2. Fit the temperature sensor (6) with the round sealing
ring (5) and screw it into the heat exchanger (4).
Tighten to 1.5 Nm ±10%.
3. Connect the electrical connections (see 9.2.1.2).
4. Install the heater (see 8.7.1.2).
