Operating instructions

5. Maintenance of the Heater
5.1 Annual Maintenance
The Thermo 90 S heater requires a minimum of maintenance to keep in good operating condition.
The following maintenance procedures should be performed annually before each heating season:
Enclosure Box and Heater
- Clean the heater and enclosure box from any accumulated debris or dust with compressed air.
- Inspect all components for wear and damage.
Electrical System
- Check wiring harnesses for damage, repair or replace if damaged.
- Check the condition of the batteries and the connections.
- Load test the batteries and replace if necessary.
Combustion Air System
- Check for obstructions at air intake port.
- Check air intake tube carefully for restrictions and damage. Repair or replace if damaged.
Exhaust System
- Check the exhaust system carefully for restrictions or corrosion. Replace damaged parts.
Fuel System
- Change fuel filter if equipped. Inspect fuel line for damage, restrictions, routing or loose
connections. Repair or replace if damaged.
Coolant System
- Inspect all coolant lines and clamps for leakage, restrictions or damage. Repair or replace.
- Inspect coolant circulation pump for leakage. Repair or replace if damaged.
Operational Test
- Run your heating system for at least 15 minutes.
- Check water and fuel connections for leakage. Re-tighten hose clamps if necessary.
- Check sleeper blower operation by turning on the thermostat, let the fan cycle on and off.
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Thermo 90 S 5 Maintenance of the Heater
NOTE
Operate your Webasto at least once a month fo 20 minutes.
NOTE
The heater will not function properly with weak batteries.
NOTE
For major repair and spare parts, return to your authorized Webasto Thermosystems Specialist.