Preparation work
- Check DTC memory and determine and repair all possible malfunctions (See «DIAGNOSTIC TROUBLE CODE (DTC) MEMORY, CHECKING (FUNCTION 02)»(/audi/a8/d2-1994-1999/remont/heated-glassdefoggers/#on-board-diagnostic-obd-hvac-can-defrosters__diagnostic-trouble-code-dtc-memory-checking) ).
- Switch ignition OFF.
- Connect high pressure hose of refrigerant recovery/recycling/recharging unit Kent-Moore ACR 4 , or equivalent, to high pressure service valve. See «HIGH PRESSURE SERVICE CONNECTION WITH SCHRADER VALVE»(/audi/a8/d2-1994-1999/remont/automatic-hvac-system/#air-conditioning__high-pressure-service-connection-with-schrader) .
- Leave low pressure hose of refrigerant recovery/recycling/recharging unit disconnected.
Note. Only a high pressure service valve is used for A/C system servicing and checking pressures. A low pressure service valve is not installed in the A/C system. Perform all A/C system pressure checks through the high pressure service valve.
| Outside (ambient) temperature (1) | Base pressure in refrigerant system (engine OFF) |
|---|---|
| +15°C (59°F) | 3.9 bar (56.5 psi) |
| +20°C (68°F) | 4.7 bar (68.2 psi) |
| +25°C (77°F) | 5.6 bar (81.2 psi) |
| +30°C (86°F) | 6.7 bar (97.2 psi) |
| +35°C (95°F) | 7.8 bar (113.1 psi) |
| +40°C (104°F) | 9.1 bar (132.0 psi) |
| +45°C (113°F) | 10.5 bar (152.3 psi) |
| (1) All components of A/C system must be at the specified temperature for an accurate pressure measurement. | |
| (1) | All components of A/C system must be at the specified temperature for an accurate pressure measurement. |
R134a TEMPERATURE AND PRESSURE RELATIONSHIP