LEMON Manuals: Even more car manuals for everyone
Home >> Mercedes Benz >> 2006 >> G500 >> Repair and Diagnosis >> Heating, Ventilation & A/C (HVAC) >> HVAC Control Systems >> HVAC Basic Knowledge -- G-Class (463) - 1 Of 2 >> Basic Knowledge >> Automatic air conditioning refrigerant circuit, function - GF83.40-P-2005G

Automatic air conditioning refrigerant circuit, function - GF83.40-P-2005G

MODEL 463.306 /336 /346 as of model year 2011 /YoM 10 

MODEL 463.202 /222 /236 /237 as of model year 2009 /YoM 08 

MODEL 463.247 /248 /249 /254 /270 /271 /303 /340 /341 as of model year 2007 

Fig 1: Automatic Air Conditioning Refrigerant Circuit Function Diagram
G07740598Courtesy of MERCEDES-BENZ USA

Function 

The refrigerant compressor driven by the engine compresses the gaseous refrigerant which heats up in the process. The compressed refrigerant flows through the condenser.

The refrigerant's compression heat is then withdrawn on the surface of the condenser. The refrigerant liquefies during cooling. If cooling by the airstream is not sufficient, the additional fan (M4) is activated and thus air is additionally drawn in to cool the condenser.

When the refrigerant flows through the fluid reservoir it is cleansed of any chemical and mechanical impurities.

The liquid refrigerant passes through the expansion valve into the front evaporator located in the fresh air flow.

In vehicles with code (HH7) Additional air conditioning in rear, refrigerant flows additionally through the rear evaporator when the rear air conditioning refrigerant shutoff valve is open. The rear air conditioning refrigerant shutoff valve is actuated by means of a direct line via the rear air conditioning control unit (N22/4) when cooling is needed.

Due to the evaporation process of the refrigerant starting in the evaporator, heat is removed from the air blowing by through the pipe and honeycomb system from the outside, thus cooling the air.

The air humidity carried along condenses and is led to the outside.

The air is thus dried.

The refrigerant compressor aspirates the refrigerant which has turned gaseous on account of the heat absorption and then compresses it yet again.

In the process, the pressure and refrigerant temperature sensor monitors the pressure and temperature of the refrigerant.

To prevent the evaporator from icing up, the refrigerant compressor is switched off by the AAC [KLA] control and operating unit (N22) when the temperature on the front evaporator drops below a certain value, or by the rear air conditioning control unit when the temperature on the rear evaporator drops below a certain value.

  Condenser, component description   GF83.40-P-2188G 
  Evaporator, component description   GF83.40-P-2189G 
  Expansion valve, component description   GF83.40-P-2190G 
  Component description of refrigerant compressor A9 GF83.55-P-2108G
  Evaporator temperature sensor, component description B10/6 GF83.57-P-2126G
  Refrigerant pressure and temperature sensor, component description B12/2 GF83.40-P-2195G 
  Additional fan, component description M4 GF83.40-P-4010G 
  Component description for automatic air conditioning control and operating unit N22 GF83.40-P-3000G