Components of the Auxiliary Heater

Components Of The Auxiliary Heater

The auxiliary heater (heating unit) is manufactured by Ebersp�cher. Most components are located behind the wheel-housing trim panel at the front left.

Heating unit of the auxiliary heater (4-zone system)

NOTE: The heating current is between 2.3 and 5.0 kW. The power consumption for this is between 12.5 and 37 W (values for partial and full load). The electric power may reach 200 W momentarily in starting mode.

The heating unit of the Cayenne has the same function and design as the heating unit on the Panamera.







Water pump

NOTE: The volume flow (pos 4) can only flow towards the intake end of the circulating pump because the large water circuit is isolated.

The electric water pump (circulating pump) is located under the heating unit. This circulating pump runs when the auxiliary heater is active and permits circulation of the heated water through the passenger compartment heat exchanger (small water circuit). The circulating pump is controlled directly by the operating and air-conditioning unit (OAU = control unit of the air conditioning system).

3/2 directional-control valve (volumetric flow)

Water flows through the passenger compartment heat exchanger when the auxiliary heater is active (small water circuit). The 3/2 directional-control valve isolates the large water circuit (engine cooling) for this purpose. As a result, the control unit for the auxiliary heating system controls the directional-control valve directly (valve is energised/armature at top).

The auxiliary heater is not designed for engine preheating at present.







Auxiliary heater metering pump

The metering pump of the auxiliary heater is located behind the rear cross-member on the left side of the vehicle and is mounted on the underbody assembly. The intake-side line of the metering pump is attached on the right side of the fuel tank and pumps fuel directly out of the pump chamber. The aspirated fuel is pumped to the heating unit on the auxiliary heater through a line mounted on the left side member.

The metering pump is controlled and clocked directly by the control unit of the auxiliary heater.