Refrigerant Circuit, General Precautions

Follow the instructions for the workplace. Refer to Volkswagen Service Net, Handbooks, Service Handbook; Protecting the Environment. They should be displayed in the workplace.
Ensure absolute cleanliness when working.
Wear work clothing, safety goggles and gloves when working with refrigerant and nitrogen.
Turn on the exhaust gas ventilation system
Use service station to discharge refrigerant circuit, only then open 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.
Be sure to close the container to prevent the refrigerant from absorbing moisture from the air.

-- Flushing refrigerant circuit with compressed air and nitrogen, refer to REFRIGERANT CIRCUIT, FLUSHING WITH COMPRESSED AIR AND NITROGEN :

-- Flush the refrigerant circuit with R134a refrigerant. Refer to REFRIGERANT CIRCUIT, FLUSHING WITH REFRIGERANT R134A .

On vehicles with A/C compressor without magnetic clutch:

NOTE:

The engine should only be started after assembling the refrigerant circuit.

If possible start engine only with a filled refrigerant circuit.

The A/C compressor is always driven by the ribbed belt pulley/torsion elastic clutch. It does not have a magnetic clutch.

If an A/C compressor locks-up the overload protection for the A/C compressor shaft is triggered. If no bumps are visible on the ribbed belt pulley/overload protection, the A/C compressor may be blocked. Another indicator is abraded rubber material in the area of the ribbed belt pulley/overload protection

The A/C compressor is equipped with a protected oil supply, this prevents A/C compressor damage in the event that the system is empty. This means that approximately 40 to 50 cm³ of refrigerant oil remains in the A/C compressor.

The engine may only be started when the refrigerant circuit is installed correctly. For example; if the refrigerant pipes are not connected to A/C compressor, when the engine is running the A/C compressor may heat up (via internal heat generation) so much that the A/C compressor will be damaged.

A/C Compressor Regulator Valve -N280- is not activated when the refrigerant circuit is empty and the A/C compressor idles with the engine.

If it is necessary to start the engine with a discharged refrigerant circuit:

Refrigerant circuit must be fully assembled.

At least 1/4 of the prescribed refrigerant oil must be in the A/C compressor.

Do not rev engine higher than 2000 rpm.

The engine should run less than 10 minutes.