This repair shop manual is intended to support familiarised personnel in the repair of the water heaters Thermo Top E, Thermo Top Z and Thermo Top C of the fuel and Diesel types. As their appearance is identical or similar, the heaters are marked by type on their identification plate with "Benzin" (fuel) or "Diesel". The heaters may only be operated with the specified type of Diesel (or with fuel oil EL) and the appropriate type of electrical installation. Heaters which have Diesel or fuel specified on their identification plate must not be operated with PME (vegetable methyl ester). Thermo Top E and C are variants of Thermo Top Z with a circulation pump.
Additional Documentation to be used
This workshop manual contains all information and procedures necessary for the repair of water heaters Thermo Top E, Thermo Top Z and Thermo Top C. The use of additional documentation is normally not necessary. Operating instructions/installation instructions and the vehicle specific installation proposal may be used as complementary information as necessary.
Webasto Diesel Heater
The heater may only be installed in vehicles or independent heating systems with a minimum coolant capacity of 4 litres. When checking the cooling water level proceed in accordance with the vehicle manufacturer's instructions. The water in the heating circuit of the heater must contain at least 10 % of a quality brand anti-freeze. Extracting combustion air from the vehicle interior is prohibited.
The water heater Thermo Top Z (supplementary heater) is intended to compensate for the shortage in heat generated by engines optimised for low fuel consumption. The water heater Thermo Top E and C (auxiliary heater) is used to:
- heat the vehicle cabin,
- defrost the vehicle windscreens,
- preheat water-cooled vehicle engines.
The heater Thermo Top Z may be converted into an auxiliary heater using a retrofit kit. The heater designed to the evaporator principle operates intermittently controlled by the temperature sensor. In order to minimise the battery's workload the heater switches from full-load operation to part-load operation after reaching a water temperature of 72° C. In this mode of operation the heater operates with extremely low noise and particularly low power and fuel consumption. The heater consists of the combustion air fan assembly, the control unit/heat exchanger, the burner insert and the combustion chamber. The Thermo Top E and C heater has an additional circulation pump.
Webasto Heater Thermo Burner Insert
Inside the burner insert fuel is distributed across the combustion pipe fuel cross section. Combustion of the fuel/air mixture takes place within the combustion pipe to heat the heat exchanger. The glow plug/flame sensor located in the burner insert ignites the fuel/air mixture during start of the heater. After start the glow plug / flame sensor operates in the flame sensor function. The glow plug / flame sensor designed as an electrical resistor is located in the burner insert opposite the flame side.
Webasto Heater Thermo Control Unit
The control unit is the central unit and ensures control and monitoring of combustion operation. The control unit is ventilated by means of a ventilation hose routed from the combustion air collector compartment of the burner.
Webasto Heater Thermo Temperature Sensor
The temperature sensor senses the coolant temperature in the heat exchanger of the heater as an electrical resistance. This signal is routed to the control unit for processing.