The heaters are cleared for heating the vehicle engine and the passenger cabin. The use of the heater in vehicles not subject to the EU Directive 70/156/EEC (e.g. ships) is partly governed by regional regulations. The heater may only be fitted in vehicles or in independent heating systems with a minimum coolant capacity of 10 liters for DBW 2010 and 15 liters for DBW 2020 and 300.
The heater must not be installed in the passenger or driver compartments of vehicles. Should the heater nevertheless be installed in such a compartment, the installation box must be sealed tight against the vehicle interior.
This repair shop manual is intended to support familiarized personnel in the repair of water heaters DBW Series:
- Webasto water heaters DBW 2010
- Webasto water heaters DBW 2020
- Webasto water heaters DBW 300
The water heater may only be operated with the fuel specified on the model plate and the relevant designated type of electrical connection.
Webasto DBW 2010/2020/300 COOLANT HEATERS
In the vicinity of the water heater a temperature of 85° C (185 °F) must not be exceeded under any circumstances (e.g. during body paint work). A violation of this temperature limit may cause permanent damage to the electronics. 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 a minimum of 20% of a quality brand anti freeze.
Additives in the heating circuit must not affect metals, plastics and rubber and must leave no deposits. The opening pressure in the vehicle cooling system normally indicated on the radiator filler cap - must be between 0.4 and 2.0 bar above operating pressure (also applicable to separate heating circuits).
LEGAL PROVISIONS FOR INSTALLATION
Webasto DBW series heaters have been type-tested and approved in accordance with EG Directives 72/245/EWG (EMV) and 2001/56/EG (heater) with the following EG permit numbers: e1*2001/56*0006*xx. Installation is governed above all by the provisions in Annex VII of Directive 2001/56/EC.
Installation Instructions for Webasto fuel tanks for the fuel supply of water heaters in vehicles:
- in vehicles the installation is not permitted in the passengers’ or driver’s compartment.
- the fuel filler neck must not be located in the passengers’ or driver’s compartment of any vehicle.
- fuel containers must either be equipped with a vent cap or any other type of ventilation (vent line).
Only vent caps in accordance with DIN 73400 may be used. All fuel containers offered in the Webasto Accessories Catalogue are suitable for a maximum operating pressure of 0.15 bar overpressure. All fuel containers offered in the Webasto Accessories Catalogue are subjected during manufacture to individual pressure testing with at least 0.3 bar overpressure. The operational state of the heater, i.e. at least an indication "on" or "off" must be easily and clearly visible. For heaters in vehicles not ruled by the EU Directive but other regulations, the acceptance by the relevant authority is required as applicable.
The water heaters Webasto DBW 2010, DBW 2020, DBW 300 and Scholastic HeaterTM are used in combination with the vehicle’s own heating installation to:
- heat the passenger compartment
- defrost the windshield
- preheat water-cooled engines
- in self-contained cargo heating applications
The water heater operates independent from the vehicle engine and is connected to the vehicle cooling system, the fuel system and the electrical system. The heater is designed to the heat exchanging principle and operates intermittently, controlled by the temperature control thermostat.
The heaters DBW 2010, DBW 2020, DBW 300 and Scholastic Heater basically consist of:
- the combustion air intake (adjustable)
- the combustion air fan and motor
- the fuel pump
- the fuel control valve and solenoid
- the nozzle holder and nozzle
- the ignition coil and ignition electrodes
- the combustion chamber
- the heat exchanger
TEMPERATURE CONTROL THERMOSTAT
After the operating temperature has been reached, the temperature control thermostat opens and shuts off the heating cycle and a purge cycle begins. Once the operating temperature drops to the lower temperature threshold of the control thermostat, the thermostat closes and another heating cycle begins, thus, maintaining a consistent coolant temperature.
The fuel pump (single-staged toothed gear pump) delivers the fuel from the tank to the heater and brings it to a pressure of 10 ± 0.5 bar (145 ± 7 psi) for DBW 2010*, DBW 2020 and DBW 300. *DBW 2010 equipped with a 0.35 Gal/hr. nozzle only. For DBW 2010 with 0.40 Gal/hr. nozzle, the fuel pressure should be set to 8 – 0.5 bar (116 – 7 psi).