Volkswagen Golf / Golf GTI / Jetta. Manual - part 996

 

a tendency to increase the greenhouse effect.

 

Conversion programs are available for old existing systems 
filled with the ozone-depleting substance R12.

 Repair Manual for A/C systems with refrigerant R12 

For environmental protection reasons, refrigerants must not 
be released into the atmosphere 

 

00-3, Laws and 

regulations

 (laws and regulations). 

Mode of operation of air conditioning 
system

 

 

The temperature in the passenger compartment depends 
on the amount of heat radiated through the windows and 
conducted by the metal parts of the body. In hot weather it 
is possible to achieve a more comfortable temperature for 
the passengers by pumping off some of the heat.

 

As heat spreads into cooler areas, the passenger 
compartment is equipped with a unit for generating low 
temperatures with constant evaporation of refrigerant. The 
heat required for this is extracted from the air flowing 
through the evaporator.

 

After absorbing heat, the refrigerant is pumped off through 
the compressor. The action of the compressor increases 
the heat content and temperature of the refrigerant. Its 
temperature is then substantially higher than that of the 
surrounding air.

 

The hot refrigerant flows with its heat content to the 
condenser, where the refrigerant dissipates its heat to the 
surrounding air via the condenser due to the temperature 
gradient between the refrigerant and the surrounding air.

 

The refrigerant thus acts as a heat transfer medium. As it is 
to be reused, the refrigerant is returned to the evaporator.

 

For this reason all air conditioning systems are based on 
the refrigerant circulation principle. There are however 
differences in the combination of aggregates.

General work safety

 

- As per VBG 20, German industrial liability insurance 
association. 

- Observe workshop specific instructions 

 Environmental 

Protection Vol. 2-2. 23.0) , which must be hung in the 
refrigerant workshop. 

General information for A/C system

13/2/2005

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 
vessels 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.

Refrigerant, handling

 

Warning!  

 

There is a danger of ice-up.

 

Refrigerant may escape in liquid or vapor form.

 

Do not open vessels which store refrigerant.

 

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

 

The pressure level is governed by two factors:

- The type of refrigerant in the vessel. "Rule: The lower the 
boiling point, the higher the pressure." 

- The temperature level. "Rule: The higher the temperature, 
the higher the pressure." 

Wear protective goggles

 

 

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

Wear protective gloves and apron

 

 

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.

Do not allow liquid refrigerant to come into 
contact with the skin

 

General information for A/C system

13/2/2005

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   C at ambient pressure). 

Do not inhale refrigerant vapor

 

Note: 

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

Absolutely no smoking

 

 

A burning cigarette can cause refrigerant to decompose. 
The resultant substances are toxic and must not be 
inhaled.

Welding and soldering on refrigeration systems

 

 

Before performing welding or soldering work on vehicles in 
the vicinity of air conditioning system components, extract 
refrigerant and remove remnants by flushing 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 
clothing affected and rinse skin with copious amounts of 
water. 

- Following inhalation of highly concentrated refrigerant 
vapors, person concerned is to be taken immediately into 
the open air. Call a doctor. Administer oxygen in the event 
of breathing difficulties. If the person affected is having 
great difficulty breathing or is not breathing at all, tilt back 

General information for A/C system

13/2/2005

head at neck and administer artificial respiration. 

Pressure vessels, handling

 

- Secure vessels 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 vessels! 

 

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

 

Valves may break off if cylinders are not properly 
transported. To protect the valves, cylinders are only to be 
transported with protective cap screwed on.

- 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 vessel pressure may be 
exceeded.

Do not heat above 50   C 

To avoid possible risk, pressure vessel regulations specify 
that vessels are not to be heated to in excess of 50   C. 

Do not heat in an uncontrolled manner

 

 

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

Seal empty vessels

 

 

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

Safety regulations for working with extraction 
and charging systems

 

- Make sure the shut-off valves are closed before 
connecting the charging system to the air conditioning 

General information for A/C system

13/2/2005