A/C System - Manual

SYSTEM DESCRIPTION
The R-134a air conditioning system uses a hydrofluorocarbon (HFC) (non-CFC) based refrigerant. R-134a requires the use of Motorcraft YN-12b refrigerant oil or equivalent meeting Ford specification WSH-M1C231-B. Do not use R-12 tools and equipment when repairing a R-134a system unless specified in the workshop manual. Never mix R-12 and R-134a refrigerants and oils. They are not compatible.

A/C System
The A/C system is a multi-piece, single case design, with an integral blower. The system allows the operator to control the temperature by delivering heated or cooled air to maintain a constant temperature. In addition, during A/C operation, it reduces the relative humidity of the air inside the vehicle. Controls are provided to adjust the temperature and system functions, including blower motor speeds for desired airflow. Outside air is drawn from the cowl air inlet just below the windshield during all system operations except for MAX A/C cooling (when recirculated air is used) and OFF. Temperature control can be maintained in all control settings except when the system is turned OFF. For more information on the air conditioning system.

Refrigerant Circuit:

REFRIGERANT CIRCUIT WITH A FIXED ORIFICE TUBE
The compressor draws the gaseous refrigerant in from the front and compresses it. In so doing it is heated to a temperature of between 70°C and 110°C.

The gas is then pumped to the condenser. The condenser consists of numerous cooling fins, through which the gas passes. The refrigerant gas is cooled both by the external air flow and depending on the vehicle model by the auxiliary or radiator fan until it condenses.

The condensed liquid refrigerant then passes through a fixed orifice tube with a constant diameter. The pressure behind the orifice tube drops, the temperature falls rapidly as a result, and the refrigerant partially vaporizes.

The fixed orifice tube is mounted in front of the evaporator within the refrigerant line, in which complete evaporation takes place. As a reset, the evaporator and the air flowing past it are both cooled.

The cooled air is blown by the heater/air conditioning blower through the air distribution system into the vehicle interior.

The refrigerant gas then passes through the suction accumulator/drier before it is drawn into the compressor again.