Heating, Ventilation and Air Conditioning

Refrigerant Circuit with Expansion Valve

3steps
~18min
2/5difficulty
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A-Low pressure side of refrigerant circuit.

B-High pressure side of refrigerant circuit.

Refrigerant Circuit with Expansion Valve
Component Aggregate State of Refrigerant Pressure bar (psi) Positive Pressure Temperature in Degrees Celsius (Fahrenheit)
-1- Evaporator, from input to output Vapor Approximately 1.2 (17.4) → Note Approximately -7 (20) → Note
(Approximately 1.8 (26.1)) → Note Approximately -1 (30) → Note
-2- A/C compressor A-side Gas Approximately 1.2 (17.4) → Note Approximately -1 (30)
(Approximately 1.8 (26.1)) → Note Approximately -1 (30) → Note
-3- A/C compressor B-side Gas Approximately 14 (203.1) Approximately 65 (149)
-4- Condenser Gas, vapor, fluid Approximately 14 (203.1) Approximately 55 (131) at outlet
-5- Receiver Fluid Approximately 14 (203.1) Approximately 55 (131)
-6- Extraction and filling valve, B-side Fluid Approximately 14 (203.1) Approximately 55 (131)
-7- Expansion valve Fluid, released as vapor Approximately 14 (203.1) Approximately 55 (131), reduced to -7 (20)
-8- Extraction and filling valve, A-side Gas Approximately 1.2 (17.4) → Note Approximately -7 (20) → Note
(Approximately 1.8 (26.1)) → Note Approximately -1 (30) → Note
  1. Pressure in refrigerant circuits is maintained at approximately 2 bar (29 psi), regulated by A/C compressor, even though heat transfer changes and engine speeds vary. However, this applies only within the performance range of the A/C compressor; if the performance limits of the A/C compressor are exceeded, the pressure increases. Refer to → Chapter "Pressures, Checking".
  2. Within the control range of the A/C compressor, temperature in the refrigerant circuits is maintained, regulated by A/C compressor, even though heat transfer changes and engine speeds vary. However, this applies only within the performance range of the A/C compressor; if the performance limits of the A/C compressor are exceeded, the temperature increases. Refer to → Chapter "Pressures, Checking".
  3. Measured values for A/C systems with two evaporators
Note A/C compressors which do not regulate their performance are switched off by the respective control module via the A/C Compressor Regulator Valve -N280- at an evaporator temperature below 0 C (32 F). In vehicles with A/C Compressor Regulator Valve -N280-, the pressure is modified on the low pressure side by the valve.

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