Refrigerating fluid

The above parts are connected to one another by suitable hoses. On the hose connecting the condenser to the evaporator a three- level pressure switch has been fitted and this is the only part of the system with control and safety functions.
An expansion valve has also been inserted in the same hose.

• High pressure circuit
• Low pressure circuit

1. Flow of air to cool the condensor leading from the front grille when the vehicle is on the move.
2. Flow of air to cool the condenser generated by the corresponding fan when the car is at a standstill or travelling slowly (queues).
3. Flow of air for the evaporator generated by the corresponding fan installed in the heater - distributor unit.

1. Compressor
2. Condenser
3. Condenser fan
4. Expansion valve
5. Evaporator
6. Evaporator fan
7. Drier filter
8. Three-level pressure switch (trinary)

The air conditioner unit cools and dehumidifies the air before it reaches the passenger compartment. It operates according to a common refrigeration cycle containing R134a fluid exploiting the change from liquid to gas and viceversa to absorb and release a considerable amount of heat.
During operation, two pressure levels are created which are maintained on one side by the compressor and on the opposite side by the expansion valve at the evaporator inlet. Two needle valves are fitted on the hoses for charging and draining the system.
The refrigerating fluid leaves the compressor as a gas at high temperature and high pressure. It then enters the condenser where it is cooled and comes out as a liquid.
The expansion valve located on the evaporator inlet atomizes the fluid and lowers its pressure which leads to a decrease in its temperature.
The fluid which is still in a liquid state enters the evaporator where it is vapourized absorbing heat from the air directed onto the fins of the fan.
The air in contact with the cold walls of the evaporator loses a high percentage of its humidity which, when condensed is drained outside the car through a special drainage tube.
The fluid in a gaseous state leaves the evaporator and passes into the drier filter which absorbs any particles of water which, if allowed to continue around the circuit would freeze and block the expansion valve reducing or eliminating the efficiency of the cycle.
A three-level pressure switch is inserted in the high pressure circuit of the refrigerating fluid near the drier and controls the turning on and off of the compressor.

Refrigerating fluid

For the above air conditioning system the new ecological fluid R134a is used which does not contain chlorofluorocarbon (CFC), one of the chemical agents that causes the reduction of the ozone layer of the atmosphere.
The systems working with R134a are readily distinguished by the wording "R134a" printed on its main components.

Refrigerating fluid R134a cannot be mixed with the Freon 12 used in the conditioning systems of the previous cars; therefore, NEVER USE FREON 12 FOR ANY REASON WHATSOEVER for the conditioners with R134a.
All the components of the system are specifically for the use of R134a and ARE NOT INTERCHANGEABLE with those of the cars using R12.
The draining/recovery station is specifically for R134a fluid.
(Refer to the specific Tool Bulletins for further details).