Webasto Heater BBW 46, DBW 46 Installation Instructions

Webasto Heater BBW 46, DBW 46 Installation Instructions
Webasto Heater BBW 46, DBW 46 Installation Instructions

Installation Location Webasto BBW 46 / DBW 46
Preferably, the heater should be installed in the engine compartment in the splash-water protected area of the front fenders or at the splash wall. The heater should be installed at a level as low as possible so as to ensure automatic venting of the heater and the circulating pump. . This is of special importance since the circulating pump is not of the self-priming type.

Type Plate
The type plate must be located at a place where it is protected against damage and where it can be easily viewed once the heater has been installed (or else, a type plate duplicate is to be used). The years not applicable must be removed from the type plate.

Connection to the Vehicle’s Cooling System
The heater is to be connected to the vehicle’s cooling system in accordance with Figs 3, 4, 5 and 6. A minimum of 4 litres of coolant must be maintained in the cooling circuit. The integration of the heater into the cooling circuit is to be performed in the flow line of the vehicle’s heat exchanger. As a rule, the water hoses supplied by Webasto with the heater should be used. If this is not the case, the hoses must comply with DIN 73411 requirements as a minimum. The hoses are to be routed without any kinks and – to ensure proper venting – in an upward pitch, if possible. Hose connections must be secured against slipping off by means of hose clamps.

NOTE:
When securing the hose clamps to the heater, be sure to fit them between the bead (thicker part) of the hose and the heater. The hose clamps must be tightened to a torque of 2.0 + 0.5 Nm.

Before the heater is started up for the first time, or after the coolant has been replaced, it must be ensured that the cooling system is properly bled. Heater and piping should be installed in such a way that static bleeding of the system is ensured.During heating operation, inadequate bleeding may lead to
a malfunction due to overheating.

Re-Positioning of Circulating Pump
The circulating pump may be integrated into the water circuit either by installation at the location provided on the heater or at a heater-remote location. It is important that the correct direction of flow through the heater be observed (water outlet at top / water inlet at bottom) as otherwise malfunctions will occur!

Connection to the Fuel System
Fuel system integration without non-return valve in the tank The heater’s fuel supply circuit must be integrated in the return line as shown in Fig. 3. Fuel system integration with non-return valve in the tank or fuel system integration in the case of singleline fuel supply Tank extractor with 90°-elbow is to be installed in the tank fitting (Fig. 7)

The fuel pick-up is to be mounted so that any air or gas bubbles that may form are automatically discharged toward the tank (see Fig. 10). Air or gas bubbles in the fuel line of the vehicle can form if there is a leak in the vehicle’s carburettor or fuel pump, or if the ambient temperature exceeds the evaporating temperature of the fuel. Fuel should not be extracted in the vicinity of the engine since here gas bubbles are likely to form in the lines owing to the heat radiating from the engine, which may result in malfunctions of the combustion operation.

If the heater is installed in vehicles with petrol injection systems it must therefore be determined whether whether the fuel pump is mounted inside or outside the tank. Where the fuel pump is located inside the tank, the fuel can only be drawn from the return pipe in which case it must be ensured that the return pipe extends almost to the bottom of the tank. If this is not the case, it is possible to extend the return pipe. Where the fuel pump is mounted outside the tank, the connection to the fuel system can be accomplished between the fuel tank and the fuel pump.

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