11.1. Heating and ventilation

Elements of automatic system of heating (HAU)
Check of work of system of heating and ventilation
Replacement of the filter of the air coming to salon
Fan of stitched air
Search of malfunctions of the fan
Removal of the electric motor of the fan
Possible malfunctions of system of heating, their reason and ways of elimination




Fig. 10.1. The system of heating and ventilation with system of climate control in models of the E-class is equipped with two filters (1) with absorbent carbon and one filter (2) purifications of the air coming to salon. Cases of coal filters are placed behind the fan, the dust filter is located in front of the fan. Thanks to it air also undergoes cleaning in the recirculation mode


The car is serially equipped with automatic system of heating with electronic control and the filter of purification of the air coming to salon with separate adjustment, traditional for the Mercedes cars, for the driver and the forward passenger. As the additional equipment the conditioner or system of climate control (fig. 10.1) can be installed.
On E-class models from six - and eight-cylinder engines, and also on all cars with the conditioner for improvement of circulation of liquid in system of heating the additional pump with the electric drive is installed.
Inflow of fresh air to system of heating happens through an inlet opening under a windshield. Air passes through the case of a heater and is distributed by system of various gates on separate air ducts to ventilation deflectors. At installation of a heater on heating of the gate of system in a motor compartment open access to a heater radiator. The radiator is in the case of a heater and is warmed up by hot cooling liquid of the engine. Pritochny air, passing through hot plates of a radiator, heats up and then moves in salon.
The control unit and adjustments is located in the center of the dashboard and consists of two rotary regulators of temperature and electronic system of installation of temperature. The established values of temperature (preset values) are compared by temperature sensors to the current values (actual). Depending on it there is a control of the dual valve. The period of opening is connected with a divergence between the set and actual values of temperature.
The circulation valve (the dual valve) is located in the assembly block in the right part of a motor compartment. The dual valve consists of two interdependent electromagnetic valves installed in the uniform block. Each valve is installed in system of circulation of cooling liquid and opens for her access through the corresponding heat exchanger. So, for example, if for heating full capacity is necessary, the valve is open constantly. On the contrary, at the switched-off heating valves are closed. When temperature is regulated by automatic equipment, at the included ignition it is often possible to hear operation of the valve. Through electric contact tension moves on both magnetic coils of valves. The magnetic anchor under the influence of magnetic field moves down, and the saddle of the valve blocks a stream of cooling liquid. When tension does not move, the valve is open.
The pump of circulation is installed under the air filter sideways in the right side of a motor compartment. At the included ignition and work of system of heating the pump pumps over cooling liquid via the heat exchanger. At the same time it supports the main pump of cooling liquid. After an engine stop the pump of circulation continues to support circulation of cooling liquid independently. Thus, heating can happen until all heat from the engine is spent. The chain of connection of the pump is protected by a safety lock No. 3. Connection to "weight" is carried out via the automatic control unit and adjustments by system of heating.