T
HERMO
90 / 90 S
8SERVICING
8-1
8. Servicing
8.1 General
This section describes the servicing procedures that may
be performed with the heater installed.
8.2 Work on the Heater
Prior to performing any work, it is mandatory to
disconnect the vehicle battery main lead. As long as the
heater is in operation or in run-down, the battery main
supply must not be disconnected due to the danger of
overheating and resulting in a response of the overheat
protection. When performing extensive repairs on the
heater, a complete removal is advisable. After work on
the heating circuit, a coolant mixture consisting of water
and anti-freeze must be replenished in accordance with
manufacturer instructions followed by a careful bleeding
of the heating circuit.
When performing repairs requiring a relocation of the
installation position, the relevant installation instructions
and the vehicle-specific installation proposal have to be
observed.
8.3 Work on the Vehicle
CAUTION
In the vicinity of the heater, a temperature of 130 °C
(266 °F) must not be exceeded under any circumstances
(e.g. during body paint work).
8.4 Heater Test Run
WARNING
The heater must not be operated, not even with timer, in
enclosed areas like garages or workshops not equipped
with an exhaust venting facility.
8.5 Annual Maintenance
Before or after each heating season the following
maintenance procedures should be performed to
maintain the heater's functional reliability:
Heater and Enclosure
• Clean heater exterior and interior of enclosure of any
accumulated debris and dust with compressed air or
water. Do not force water into electrical connections
or into heater.
Electrical System
• Examine electrical connections for corrosion at
connections and for security.
• Examine battery condition and clean terminals.
• Load test batteries and replace as necessary.
Combustion Air and Exhaust System
• Check exhaust and combustion air tubes for damage
and for foreign matter and contamination. Repair or
replace damaged items as necessary.
Fuel System
• Replace fuel filter P.N. 487171 if equipped.
• Examine fuel lines and fuel filter for leakage and
damage. Repair or replace damaged items as
necessary.
Coolant System
• Examine coolant circuit and circulation pump for
leakage and damage.
• Examine hoses for abrasions and cracks.
• Check coolant level and anti-freeze strength. Refer
to vehicle manufacturer’s recommendations
pertaining to coolant system maintenance.
Operational Test
• Operate the Webasto heater for 15 minutes or more.
• Check coolant and fuel connections for leakage.
Re-tighten clamps as necessary.
• Check sleeper blower operation by turning on the
thermostat. Allow the fan to cycle on and off to
ensure proper functioning.
