Residual engine heat utilization system, function - GF83.75-P-2000Q

MODEL 209.3 except CODE (581b) Convenience automatic air conditioning with CODE (670a) Residual engine heat utilization (REST) 

MODEL 209.3 with CODE (581b) Convenience automatic air conditioning 

MODEL 209.4 except CODE (581b) Convenience automatic air conditioning with CODE (670a) Residual engine heat utilization (REST) 

MODEL 209.4 with CODE (581b) Convenience automatic air conditioning 

Function 

Residual engine heat utilization enables the vehicle to be heated even when the ignition is OFF. To do so the system utilizes the residual heat from the engine and leads it into the passenger compartment via the blower motor (A32m1). The residual engine heat utilization is only possible when the ignition is switched off.

After actuation of the REST button on the AAC control and operating unit (N22) (without code (581b) comfort automatic air conditioning) or on the comfort AAC control and operating unit (N22/7) (for code (581b) comfort automatic air conditioning) the following program run is prescribed: 

• Blend air flaps controlled
• Coolant circulation pump (M13) ON
• The blower capacity of the blower motor (A32m1) is automatically set to 25 %
• Footwell flaps 100 % OPEN
• Defroster vent flaps 66 % OPEN
• Ventilation flaps 24% OPEN
• Fresh air/recirculated air flap in fresh air position
• Defroster and footwell flaps are automatically adjusted for 60 sect (defroster function Flash-Fog logic)
• Activated charcoal filter flap open (no activated charcoal filter operation possible, only with convenience automatic air conditioning)

End of program 

• Repeated rest button pressing
• Expiration of the time function of 30 min. (repeated actuation possible)
• At a battery voltage of less than 11 V the LED flashes
• Ignition ON

During the residual engine heat utilization function no function buttons are accepted except the rest button and the temperature setting.