Audi Q5 Owners & Service Manuals

Audi Q5: Pressure Gauge, Tests and Measurements

General Information

Indicators on pressure gauge

1 - Temperature scale for refrigerant R134a CF3-CH2F or CH2F-CF3.

2 - Pressure scale

  Note

Pressure is measured in different units: 1 MPa (145 psi) corresponds to 10 bar (145 psi) positive pressure. 1 bar (14.5 psi) absolute pressure corresponds to 0 bar/psi positive pressure and thus to the ambient pressure (atmospheric pressure).

The pressure gauge may have one or more temperature scales next to the pressure scale. The R134a scale values are allocated respectively in the vapor pressure table. Since various refrigerants create different vapor pressures at the same temperature, each temperature scale is identified for the respective refrigerant.

Audi Q5. V87-1470

Pressure Gauge Uses

Pressure and Temperature Measurement at Refrigerant Circuit

  • High pressure gauge measures pressure and temperature, which expand uniformly from outlet of A/C compressor via the condenser up to constriction (restrictor, or expansion valve) with A/C system switched on.
  • Low pressure gauge measures pressure and temperature, which expand uniformly from constriction (restrictor, or expansion valve) via evaporator up to input of A/C compressor with A/C system switched on.

  Note

The relationship between pressure and temperature indicated on the gauges only exists in a refrigerant circuit that contains liquid or vapor, but not gas. In a gaseous state, the temperature is approximately 10 ºC to 30 ºC (50 ºF to 86 ºF) higher than indicated on the gauge.

Verification of Refrigerant in a Closed Container

Refrigerant R134a is present in a closed container or in a refrigerant circuit when temperature indicator on the pressure gauge matches the refrigerant temperature (standing fluid adopts the ambient temperature).

A closed container or a refrigerant circuit which has been switched off is empty when temperature indication on the pressure gauge is below the temperature of the refrigerant.

  Note

The relationship between pressure and temperature indicated on the gauges no longer applies if no liquid is present and the pressure is built up solely by gas.

    READ NEXT:

     Service and Recycling Units

    Extraction System Group Classifications At this time, service units for extracting, cleaning and filling refrigerant for motor vehicle A/C systems are available on the market from various manufactur

     Laws and Regulations

    General Information   Note The laws and regulations listed below are applicable in Germany. Different or additional laws and regulations may apply in other countries. The effects of climate ch

     Refrigerant Circuit

    SEE MORE:

     Windshield

    Overview - Windshield   Note In vehicles with lane assist, the camera must be recalibrated after replacing the windshield. Refer to → Suspension, Wheels, Steering; Rep. Gr.44; Lane Assist; Lane Assist, Calibrating. 1 - Windshield Distance to roof dimension -a-

     Tire pressure

    Fig. 206 Driver's side B-pillar: tire pressure label Fig. 207 Tire pressure label The correct tire pressure for tires mounted in the factory and for the collapsible spare tire is indicated on a label. The label is located on the B-pillar > fig. 206, > fig. 207. When the vehicle is partially

    © 2019-2024 Copyright www.audiq5.net