T
HERMO
90 / 90 S
8SERVICING
8-7
8.7 Removal and Installation
CAUTION
It is permissible to service the heater in the installed
position only if sufficient space is available for removal
and disassembly of the various components of the
heater. Should there not be sufficient space or there
exists a possibility of damage to the components of the
heater during disassembly, the heater must be removed
from the installed position.
8.7.1 Heater, Removal and Installation
8.7.1.1 Removal
1. Disconnect battery terminal leads.
NOTE:
On the Thermo 90 S heater, with control unit flanged to
combustion air fan, only connectors X12 and X13 require
disconnection from control unit.
2. Remove top cover.
3. Disconnect plug of cable loom from heater.
4. Disconnect fuel inlet on heater.
5. Loosen hose clamps and disconnect coolant hoses
from heater.
6. Disconnect combustion air intake and exhaust outlet
tubes at heater.
7. Remove three nuts and washers from heater mount.
8. Remove heater.
8.7.1.2 Installation
1. Locate heater in installation position and secure with
three nuts and washers.
2. Reconnect coolant hoses and secure with hose
clamps. Torque tighten clamps to 5 Nm.
3. Reconnect fuel line to heater.
4. Reconnect combustion air inlet and exhaust outlet
tubes at heater.
NOTE:
On the Thermo 90 S heater, with control unit flanged to
combustion air fan, reconnect connectors X12 and
X13 to control unit.
5. Connect plug of cable loom to heater.
6. Plug on top cover and arrest.
7. Reconnect battery terminal leads.
8. Bleed fuel supply system.
9. Bleed coolant circuit.
8.7.2 Replacement of Circulation Pump
NOTE:
The procedure for replacement of the circulation pump is
identical with the heater removed or installed.
Replacement is to be performed in accordance with
instructions described in section 9.2.2.
8.7.3 Replacement of Temperature Limiter
NOTE:
The procedure for replacement of the temperature limiter
is identical with the heater removed or installed.
Replacement is to be performed in accordance with
instructions described in section 9.2.3.
8.7.4 Replacement of Temperature Sensor
NOTE:
The procedure for replacement of the temperature
sensor is identical with the heater removed or installed.
Replacement is to be performed in accordance with
instructions described in section 9.2.4.
8.7.5 Replacement of Combustion Air Fan
NOTE:
The procedure for replacement of the combustion air fan
is identical with the heater removed or installed.
Replacement is to be performed in accordance with
instructions described in section 9.2.5.
8.8 First Operation
After installation of the heater, the fuel supply system and
the cooling circuit must be thoroughly bled, observing the
vehicle manufacturer's instructions. During the test run
of the heater, all connections are to be checked for
leakage and tightness. Should the heater assume an
error lock-out condition during operation, perform
troubleshooting (see Section 5).
