Heating and Air Conditioning: Description and Operation
VEHICLE APPLICATION
E-150 Through E-350.
DESCRIPTION
An auxiliary climate control system is available as an option that can be used in combination with Some of the main climate control system The chart in Fig. 1 lists the main and auxiliary system applications.
The auxiliary system is available as a combination air conditioning and heating system if the main system has the same combination Fig. 2 illustrates the components of a typical auxiliary air conditioning and heating system.
The interior components of the system are mounted on the LH side of the vehicle, between the side windows and floorpan and rearward of the driver's seat All components, including the blower motor and wheel, resistor, wiring grommet and seal, A/C core and seal, heater core and seal, and expansion valve, are serviceable from the inside of the vehicle
To remove any of the components, it is necessary to remove the auxiliary A/C-heater cover assembly and the first bench seat on vehicles so equipped. To service the heater and/or air conditioner as an assembly, it is also necessary to remove the LH side window garnish moulding and loosen the forward portion of the auxiliary duct assembly. The duct assembly is attached to the side of the body with ten screws.
Control Assembly
Fig. 3 illustrates the type of control assembly that would be installed when: 1) the vehicle is equipped with an A/C-heater system or 2) equipped with a heater only system. From the location of the control in the instrument panel, the driver and front seat passenger have access to the function and temperature levers in the main system, as well as to the separate switches that control blower motor speeds in the main and auxiliary units.
The auxiliary blower switch provides four operating speeds (HIGH, MEDIUM HIGH, MEDIUM LOW, and LOW) plus an OFF position. This switch is located near the right edge of the control assembly. The auxiliary blower switch will not function in any of its operating positions unless the function selector lever in the main system is in a position other than OFF.
Function Selector Lever
In addition to using the thumbwheel louver control in the four (of five) rearward auxiliary duct registers, the rear seat passengers can adjust airflow with a 3-position function selector lever. Refer to Fig. 4.
As shown, a door operated by the lever can be set fully forward to direct all airflow to the four rear duct registers. (The forward duct register is located ahead of the function lever. As a result, it is not affected by lever position.) With the door in the middle position, airflow is directed in approximately equal quantities to the duct register and floor outlets With the door in the fully rearward position all air is directed through the floor outlets.
Expansion Valve
The expansion valve automatically regulates the flow of refrigerant into the evaporator, and is the dividing point in the system between high and low pressure refrigerant Refer to Fig 5.
The temperature sensing bulb, clamped to the suction (outlet) tube on the evaporator, measures the temperature of the refrigerant in the suction tube and transmits the temperature variation to the expansion valve This temperature variation regulates the refrigerant (R-12) flow to the core When the bulb senses a high temperature, the valve opens and floods refrigerant through the evaporator core. When the bulb senses a low temperature, the valve starts closing to shut oft the refrigerant to the evaporator core.
Auxiliary A/C-Heater Cover Assembly
The cover assembly is attached to the body with sixteen screws on both van and club wagon vehicles. On vehicles so equipped, the first bench seat must be removed to service the cover assembly. The auxiliary duct assembly must be installed prior to installing the cover assembly. Refer to Fig. 6.
On vehicles not equipped with an auxiliary A/C-heater duct assembly, a register assembly is attached to the discharge opening as shown in Fig. 7.
To remove the auxiliary A/C-heater duct it is necessary to remove the cover assembly, LH body side window garnish moulding, and the first two bench seats on vehicles so equipped. The duct assembly is attached to the body by fifteen screws on club wagon vehicles, seven screws on van vehicles and four screws on Super Wagon vehicles.
To access the function selector lever and door for service, it is necessary to remove the auxiliary duct assembly from the vehicle, and the duct outer panel from the duct inner panel.
Registers
The five register assemblies can be adjusted to direct air as desired (Fig. 8). The register louvers can be closed to block most of the airflow. The forward register assembly can be rotated to totally block the airflow. To remove the register, pry on the end pivot with a thin blade to separate the pivot from the pivot hole and pull the barrel assembly from the register housing The pivot ends of the barrels may have different sizes to control register position when installed.