Basic Rules

Basic Rules For Working On Refrigerant Circuit

General
- Follow workplace-specific instructions (refer to Audi-ServiceNet, Handbooks, HSO Environment 2-2. 23.0).
- Ensure absolute cleanliness when working.
- Wear safety goggles and gloves when working with refrigerant and nitrogen.
- Workshop extraction systems are to be switched on.
- Use service station to discharge refrigerant circuit, then unfasten screw connections and replace malfunctioning components.
- Use caps to seal off opened assemblies and hoses to prevent ingress of moisture and dirt.
- Make exclusive use of tools and materials intended for refrigerant R134a.
- Re-seal opened refrigerant oil vessels to guard against moisture.

NOTE:
- After completing service work, screw sealing caps (with seals) onto all connections with valves as well as service connections.
- Before starting up air conditioning system, pay attention to vehicle-specific capacities.
- Do not top up refrigerant. Extract existing refrigerant and re-charge system.

Refrigerant circuit, cleaning
- Flush refrigerant circuit with compressed air and nitrogen if:
- Moisture or dirt has penetrated into refrigerant circuit (e.g. following an accident)
- Refrigerant oil is dark and viscous
- There is too much refrigerant oil in the refrigerant circuit after compressor replacement
- The compressor had to be replaced on account of "internal" damage (e.g. noise or no output)

NOTE: When flushing components with compressed air and nitrogen, always extract the gas mixture escaping from the components using suitable extraction units (workshop extraction system).

Additional notes for vehicles with compressor with no A/C clutch (with A/C Compressor Regulator Valve N280)
- The engine is only to be started following complete assembly of the refrigerant circuit (constant compressor operation).
- If engine has to be operated with the refrigerant circuit empty, only do so for as long as absolutely essential and avoid high engine speeds.

O-rings
- Make exclusive use of seals which are resistant to refrigerant R134a and the related refrigerant oils. Color coding of O-rings is no longer employed. Black and colored O-rings are used.
- Pay attention to correct ID of seals used Parts list and Heating, air conditioning; Servicing refrigerant circuit or Air conditioning; Servicing refrigerant circuit.
- Seals are only to be used once.
- Before installing, moisten seals slightly with refrigerant oil (PAG oil).

Before Starting Up Air Conditioning System After Fresh Charging
- Rotate compressor roughly 10 times by hand using the clutch plate or pulley of the A/C clutch.
- Start engine with air conditioning system switched off ( A/C Clutch N25 and A/C Compressor Regulator Valve N280 are not actuated).
- Following engine idling speed stabilization, switch on compressor and run it for at least 10 minutes at idling speed with maximum cooling output.