Fiat 1998 Marea Weekend, Service Manual

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Marea-Marea Weekend
99 range
Auxiliary units
Climate control
50.
FOUR STAGE PRESSURE SWITCHThe four stage pressure switch has the task of activating the engine
coolant radiator and condenser cooling fan when the vehicle is stationary or driving in traffic and the flow
of air produced by the vehicle moving forward is insufficient and the condensation of the R134a fluid
must be activated through ventilation: contact (II) closes at around 15 bar (engagement of first speed),
whilst contact (III) closes at around 20 bar (engagement of second speed). In addition, the three stage
pressure switch is designed to de-energize the compressor pulley electro-magnet coupling when, in spite
of the action of the fan or as a result of its failure to operate, the pressure of the refrigerant fluid (high
pressure side) reaches dangerous levels (contact IV - beyond about 25 bar) or when, as a result of a pos-
sible leak or because the outside temperature is below 10 degrees C (and the thermal load conditions are
not sufficient to evaporate the R134a fluid) the pressure of the fluid reaches a value below around 2.5 bar
(contact I).
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