Audi A4 Owners & Service Manuals

Audi A4: General Safety Precautions

  • As per VBG 20, German industrial liability insurance association.
  • Pay attention to the workshop-specific instructions. It should be kept in the workshop.

Product Characteristics

Refrigerants used in motor vehicle air conditioning systems belong to the new generation of refrigerants based on chlorine-free, partially fluorinated hydrocarbons (H-FKW, R134a).

With regard to their physical properties, these are refrigerants which have been liquefied under pressure. They are subject to the regulations governing pressure containers and use is only to be made of approved and appropriately marked containers.

Compliance with specific conditions is required to ensure safe and proper use.

Handling Refrigerant

If refrigerant containers are opened, the contents may escape in liquid or vapor form. This process is intensified the higher the pressure in the container.

The pressure level is governed by two factors:

  • The type of refrigerant in the container. "The lower the boiling point, the higher the pressure."
  • The temperature level. "The higher the temperature, the higher the pressure."


  • There is a danger of ice-up.
  • The refrigerant can then escape as a fluid or vapor.
  • Do not open containers which store refrigerant.

Protective Eyewear

Put on protective goggles. They prevent refrigerant getting into the eyes, as this could cause severe injury from exposure to cold.

Protective Gloves and Clothing

Greases and oils dissolve readily in refrigerants. They would therefore destroy the protective layer of grease if allowed to come into contact with the skin. Degreased skin is however sensitive to the cold and germs.

Fluid Refrigerant and Skin Precaution

The refrigerant draws heat for evaporation from the surrounding area. Even if this is the skin. This may cause extremely low temperatures. Local frost bite may result (boiling point of R134a: -26.5 ºC (-15.7 ºF) at ambient pressure).

Refrigerant Vapor Precaution

If highly concentrated refrigerant vapor escapes, it mixes with the surrounding air and displaces the oxygen necessary for breathing.

Welding and Soldering on Refrigeration Systems

Before performing welding or soldering work on vehicles near A/C system components, extract the refrigerant and remove remnants by blowing them out with nitrogen.

The products of refrigerant decomposition due to the effect of heat are not only toxic, but may also have a highly corrosive effect on pipes and system components. They mainly take the form of hydrogen fluoride.

Pungent Odor

A pungent odor indicates that the products of decomposition mentioned above have already formed. Avoid inhaling these substances under all circumstances, as otherwise the respiratory system, lungs and other organs could be damaged.

First Aid

  • Following contact with eyes or mucous membranes, immediately rinse with copious amounts of running water and consult an eye specialist.
  • Following contact with the skin, immediately remove affected clothing and rinse skin with copious amounts of water.
  • Following inhalation of highly concentrated refrigerant vapors, immediately take the affected person into the open air. Call a doctor. Administer oxygen in the event of breathing difficulties. If the affected person has difficulty breathing or cannot breathe, tip head back and perform mouth to mouth respiration.

Handling Pressure Containers

Secure containers to prevent them falling over!

Secure upright cylinders to stop them falling over and cylinders lying flat to stop them rolling away.

Do not throw containers!

If dropped, the containers could be so severely deformed that they rupture. The refrigerant evaporates immediately, liberating considerable force. Flying fragments of cylinders can cause severe injuries.

To protect the valves, cylinders are only to be transported with protective cap screwed on.

Valves may break off if cylinders are not properly transported.

Never store in the vicinity of radiators.

High temperatures may occur next to radiators. High temperatures are also accompanied by high pressures and the maximum permissible container pressure may be exceeded.

Not Warming Above 50 ºC (122 ºF)

To avoid possible risk, pressure container regulations specify that containers are not to be heated to in excess of 50 ºC (122 ºF).

Heating Warning

Do not heat with a naked flame under any circumstances. Localized overheating can cause structural changes in the container material, which then reduce its ability to withstand pressure. There is also a danger of refrigerant decomposition due to localized overheating.

Empty Containers

Empty refrigerant containers must always be sealed to prevent the ingress of moisture. Moisture causes steel containers to corrode. This weakens the containers walls. In addition, rust particles entering into refrigeration systems from containers will cause malfunctioning.

Extraction and Charging System Safety Regulations

  • Make sure the shut-off valves are closed before connecting the charging system to the air conditioning system.
  • Before disconnecting the charging system from the air conditioning system, make sure the charging process has been completed to stop refrigerant escaping into the atmosphere.
  • Once the purified refrigerant from the charging system has been transferred to an external compressed-gas cylinder, close the hand shut-off valves at the cylinder and charging system.
  • Do not expose charging system to moisture or use it in a wet environment.
  • Disconnect from power supply before performing service work on the charging system.
  • Never use an extension cable on account of the fire hazard. If the use of an extension cable is unavoidable, the minimum cross-section should be 2.5 mm2.
  • In case of fire, remove the external cylinder.
  • Entrained oil from the air conditioning system drawn by the suction unit into the measurement container supplied is subsequently to be transferred to a sealed container as it contains a small quantity of refrigerant. It must not be released into the environment.
  • Following shutdown, the service station is to be secured to stop it rolling away.


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