Refrigerant Circuit with Restrictor and Reservoir

WARNING: This page does not describe the selected car, but rather 17 other vehicles, including the 2009 Audi S4, 2009 Audi A4, 2008 Audi S4, 2008 Audi RS 4, and 2008 Audi A4. However, it is still accessible from the selected car via links, so may be relevant.

HP (HD) High pressure side of refrigerant circuit

LP (ND) Low pressure side of refrigerant circuit

Component	Refrigerant state	Pressure (bar)	Temperature in degrees Celsius
1 Compressor, HP (HD) side	Gas	Up to 20 bar	Up to + 70 ° C
2 Condenser	From gas to vapor to liquid	Up to 20 bar	Up to + 70 ° C
3 Restrictor	From liquid to vapor	HP (HD) side up to 20 bar LP (ND) side greater than 1.0 bar	HP (HD) side up to + 60 ° C LP (ND) side warmer than - 4 ° C
4 Evaporator	From vapor to gas	Greater than 1.0 bar	Warmer than - 4 ° C
5 Reservoir	Gas
6 Compressor, LP (ND) side	Gas

The pressures on the low pressure side are maintained at approx. 2 bar absolute pressure (corresponds to approx. 1 bar positive pressure) by the "regulating" compressor even at varying engine speeds. This however only applies within the output range of the compressor. If the output limits of the compressor are exceeded, refer to → Refrigerant Circuit, Checking Pressures with A/C Service Station .

NOTE:

On vehicles with A/C Compressor Regulator Valve N280 the pressure on the low pressure side is altered by actuating the valve.

Arrows show direction of refrigerant flow.

HD- High Pressure (HP) side of refrigerant circuit.

ND- Low Pressure (LP) side of refrigerant circuit.

Fig 1: Refrigerant Circuit With Restrictor And Reservoir Overview

Courtesy of VOLKSWAGEN UNITED STATES, INC.

1 - Compressor, HP (HD) side

2 - Condenser

3 - Restrictor

4 - Evaporator

5 - Reservoir

6 - Compressor, LP (ND) side