Electrical Systems - Chassis --- Section 9
Cayman 2005
311
Safety and Handling of 134a and Pag Oil:
• Wear eye and hand protection.
• Pag Oil irritates the skin. Flush with water immediately if in contact with any body part.
• Ensure all service work on the A/C system is performed in a well ventilated work area.
• Keep open flame away from service area. The discharge of a refrigerant near an open flame
can produce a poisonous gas.
NOTE:
O-rings required for the 134a system are Hydrogenated Nitrite Butadiene Rubber
(HNBR), and are green in color.
Air Conditioner Refrigeration Components:
Compressor - The compressor is belt driven from the engine through the compressor and elec-
tronic clutch pulley. The compressor will pump freon from a low pressure gas into a high pressure,
high temperature gas. This is the start of the refrigeration process.
Condenser - The condenser, located on Roadside in rear compartment, is made of coils and fins
which provide rapid transfer of heat from the refrigerant as external air passes over the coils. The
high pressure gas is changed to a high pressure liquid.
Condenser Fan - A steady flow of cooling air is maintained across the condenser during system
operations.
Receiver-Drier - Freon leaves the condenser, enters the receiver/dryer, located in generator com-
partment, and is stored until needed. The drier filters out moisture in the system. It only takes one
drop of moisture to cause a malfunction in the cooling unit.
Expansion Valve - The expansion valve suppresses the refrigerant into the evaporator according to
the cooling requirements. The pressure is reduced in the restrictive effort of the expansion valve. A
part of the valve is the capillary tube assembly. The capillary tube is the sensing bulb at the outlet
of the evaporator.
Evaporator - A tube core and fins are used in the evaporator similar to the condenser. Air is blown
through the fins to allow the evaporator to cool and reduce the pressure.
Blower and Motor - Just as the condenser has a fan, the evaporator has a fan called the blower.
The blower will draw air from the cab area and force the air over the evaporator coils and fins. This
forced air will ensure continuous vaporizing of the R134a.
Relays and Switches - Both electronic and vacuum switches are used in the control and operations
of the system.
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