The heater, defroster, and air conditioner have been redesigned in 1956 to give more efficient performance, to be more compact, easier to service, and to facilitate easier field installation. The radio in 1956 is unchanged except for a newly designed dial and control knobs.
11-1 HEATER AND DEFROSTER
In 1956, the heater blower and core assembly, located on all previous models under the front seat, has been completely eliminated. In 1956 the heater and defroster use a common core and blower. The core is mounted on the right shroud in approximately the same position as the 1955 defroster core. The heater and defroster blower is incorporated in the right blister in the same manner as the 1955 defroster blower. See figure 11-1.
The size of the core and the capacity of the blower in 1956 has been increased.
The blower draws outside air through the cowl air intake screen, below the windshield, into the right blister. The air is drawn from the right blister into an air hose which delivers the air to the heater-defroster core. The air flows through the heater-defroster core into the inner heater and defroster core housing where it may be directed into either the heater or defroster distribution system by means of two fly valves. For heating, the air then flows through the heater air distribution system to three heater outlets, one located at each end of the instrument panel with a third outlet located below and behind the center of the instrument panel. See figure 11-2.
The heater uses only outside air in 1956 for heating, however, when an air conditioner is installed some interior air is recirculated.
Defroster and Outside Air Ventilation
The defroster in 1956 is operated in combination with the heater. On all 1956 models the defroster and heater are installed as a single unit and cannot be installed separately. As previously stated, the same blower and core is used for defrosting and heating. The defroster air is forced into the inner heater and defroster core housing in the same manner as the heater air previously described; however, a second valve within the inner heater and defroster core housing re-directs the air through separate defroster air hoses to two defroster outlets at the windshield. The defroster outlets have been reduced from four, in 1955, to two, in 1956, without any decrease in defrosting efficiency.
The outside air ventilation system is the same in design and operation as in 1955; however, in 1956 the right and left dash ventilator valves are controlled by two push-pull type control knobs located on the instrument panel at the right and left side of the steering column.
Water Flow and Temperature Control
The hot water flows from the engine water manifold through a rubber hose into the bottom of the heater-defroster core. Water then flows out of the heater-defroster core, at the top, through a rubber hose to the Ranco valve. From the Ranco valve, water flows through a rubber hose to the bottom of the radiator.
Water flow through the heater-defroster core has been increased by over 50 % in 1956. The increased water flow is achieved by replacing the 5/8 inch Ranco valve and 5/8 inch rubber hoses used in 1955 with a 3/4 inch Ranco valve and 3/4 inch rubber hose in 1956. A new synthetic rubber valve seat is used in the 1956
Ranco valve to reduce valve leak-by.
In 1956, a “jiggle pin” has been placed in the bleed hole of the engine thermostat which allows air to escape through the bleed hole when filling the system, but seats, closing off the bleed hole when the water pump creates a small amount of pressure. The “jiggle pin” also prevents water from circulating through the bleed hole and thereby facilitates quicker warm-up when engine is cold. The quicker warm-up supplys hot water more rapidly to the heater-defroster core.
Heater, Defroster and Ventilation Operation Controls
The heater and defroster controls are located at the lower center of the instrument panel. Figure 11-3 shows the control panel which is used with just the heater and defroster installation.
Figure 11-4 shows the control panel used with the air conditioner installation.
Although the controls are positioned slightly different when an air conditioner is installed, the controls operate in the same manner as they do when only the heater and defroster are installed.
The defroster control knob is of a push-pull type and the pull knob is attached to a fly valve in the inner heater and defroster core housing by means of a bowden control wire. When the defroster knob is pulled out, the defroster valve opens and allows air to flow into the two defroster distribution air hoses. Figures 11-3 and 11-4 show the location of the defroster controls.
The blower speed is controlled by a three-way toggle switch located on the right side of the control panel. See figures 11-3 and 11-4. The switch has 3 positions, “Hi”, “Off”, and “Lo”. When switch is centered, it is in the off position. High blower speed is obtained by moving the switch to left, and low blower speed is obtained by moving the switch to right.
The heater temperature control lever, as shown in figures 11-3 and 11-4 regulates the temperature of the heater air entering the passenger compartment and is connected to the Ranco valve by a bowden control wire. As the temperature control lever is moved from left to right the heater temperature is increased.
The heater air control (upper lever) as shown in figure 11-3, when moved to the right, opens the heater valve in the inner heater and defroster core housing and allows air to flow into the heater air distribution system. The lever is connected by a bowden wire to the heater valve. When an air conditioner is installed, the heater valve is opened by moving the upper control lever shown in figure 11-4 to the right until the lever is positioned over the word “Max.”.
Inner Heater and Defroster Core Housing
The heater and defroster valves discussed previously are located within the inner heater and defroster core housing. The valves are operated by a cam type linkage in 1956 which is designed to prevent valve flutter noise. The housing and cam linkage are shown in figure 11-5.
The valves control the air flow into the air distribution hoses, running to the air outlets. When the heater is on and the defroster off, the heater valve is so positioned that air is free to flow into two air hoses. One air hose leads to the right side instrument panel outlet and the other air hose leads to the center and left side instrument panel outlets. See figures 11-2 and 11-5.
When heater air is thus directed, the defroster valve completely blocks off air flow into the defroster system. When both heater and defroster are on, both valves are partially opened, allowing air to flow through both heater and defroster system. When defroster air is desired alone, the defroster valve is opened so that all air flows through the defroster air distribution system.
The same inner heater and defroster core housing is used for cars equipped with an air conditioner unit.
11-2 AIR CONDITIONER
In 1956, air conditioner equipment is optional on all models in all Series.
In 1956 an entirely new air conditioner system is used and the unit is located in the engine compartment. The trunk evaporator-blower unit, and the Freon lines on the underframe of the 1955 models have been eliminated. See figure 11-6.
The new location of the air conditioner unit improves air distribution and air quality, and also facilitates easier servicing and installation.
In 1956 models the same air ducts and the same instrument panel outlets are used for heated and cooled air alike. See figure 11-2. This feature, along with the positioning of the evaporator coil ahead of the heater-defroster core in terms of air flow introduces in 1956 a new air conditioning effect. By cooling the incoming air and then reheating it, the air is dehumidified, achieving greater driving comfort on cool, moist days.
The refrigerant lines are made of new material in 1956. The 1956 system consists of four, synthetic, flexible rubber lines totalling approximately 9 feet in length, which will serve all series and models for installation and service.
For field installation, an air conditioner kit will be made available. The air conditioner unit will, as a kit, be fully charged with coolant with all hoses connected, and will be installed as a single unit. Therefore, installation time of the 1956 air conditioner kit should be greatly reduced.
Specific instructions on field installation will be covered in subsequent service information.
Heavy duty front springs are used in factory produced automobiles equipped with an air conditioner unit. Heavy duty front springs are not included in the field installation kit but are available at extra cost upon customer request.
- In the 1956 automobiles equipped with air conditioner, the condenser coil is mounted in front of the radiator as it was on the 1955 models. Air passing around the condenser tubes removes heat from the high pressure gas and condenses it to a liquid. The condenser thickness has been increased by 1/2 inches, thereby sufficiently increasing the area exposed to air passage to handle increased compressor capacity. Continuous rolled steel tubing is used for condenser fabrication in 1956.
- Receiver Dehydrator. In 1956 the dehydrator has been combined with the receiver, forming one compact unit as in 1955 after jobs. The receiver dehydrator performs two functions by acting as (1) a storage tank, insuring a continuous flow of liquid Freon into the expansion valve and (2) as a dehydrator removing any foreign moisture from the liquid Freon. The receiver dehydrator is located in a vertical position and is directly connected to the right side of the condenser unit. The position of the receiver dehydrator reduces the possibility of damage due to the stones and minor collision.
- Sight Glass. In 1956, the sight glass is located on the line from the receiver dehydrator to the thermostatic expansion valve. See figure 11-7.
The 1956 sight glass functions in the same manner as it did on 1955 air conditioner units.
The 1956 evaporator functions in the same manner as did the evaporator on all previous models. The cooled air, however, in 1956, is forced through ducts to the three adjustable outlets, one located on the right side, one located on the left side, and one on the top center of the instrument panel. See figure 11-9.
- The 1956 compressor is functionally the same as the Frigidaire axial type used in 1955. The compressor speed has been increased from 4000 R.P.M. in 1955 at 100 M.P.H. to 5000 R.P.M. at 100 M.P.H. in 1956. A 25 % efficiency increase has resulted from this increase in compressor speed which was achieved by reducing the diameter of compressor pulley. In 1956 the compressor main shaft has been increased in diameter and the clutch is now keyed to the shaft. The clutch has been redesigned to give greater durability at higher R.P.M. The compressor is located on the right side of the engine in the same position as in 1955. Clutch service will be covered in subsequent service information.
- Hot Gas By-Pass Valve. The w1rmg, rheostats relays, and solenoid used for temperature control in 1955 units have been completely eliminated. In their place is a single hot gas by-pass valve. The hot gas by-pass valve as used in 1956 is located near the blower on a Freon gas line running from compressor to evaporator. See figure 11-8.
This valve not only regulates the interior car temperature but prevents evaporator freeze up by keeping the evaporator gas pressure up to 30 pounds per square inch minimum at all times. This minimum pressure is maintained by a spring-loaded valve within the hot gas by-pass valve assembly.
The lower right hand temperature control lever on the instrument panel air conditioner controls is connected to the hot gas by-pass valve by a bowden wire. See figure 11-8 and 11-4. The hot gas by-pass valve is regulated according to the temperature level desired by the operator. The hot gas by-pass valve controls interior temperature by controlling evaporator pressure. The gas pressure is regulated by a variable, spring loaded valve within the hot gas by-pass valve assembly. The spring tension and resulting gas pressure is increased or decreased by moving the air conditioner temperature control. See figure 11-4. Cooling effect is reduced when the gas pressure in the evaporator is high, and is increased when the pressure of the Freon in the evaporator is decreased.
11-3 INTERIOR AIR CIRCULATION
In 1956 the air circulation in the car interior is of new Buick design. The underseat heater and rear air conditioner directors have been replaced in 1956 by four outlets, two located at either end of the instrument panel, one located at the top, and one located behind the center of the instrument panel. See figures 11-9 and 11-2. The two outlets on either end of the instrument panel are used for both heated and air conditioned air. The outlet at the top center of the instrument panel is used only for air conditioned air, while the lower outlet behind the instrument panel center is for heated air only.
The outlets on either end of instrument panel are adjustable. They may be adjusted to direct air up, down, inward toward the center of the car, or outward toward the door panels. Heated or air conditioned air is circulated to the rear seat area when the instrument panel outlets are adjusted so that air is directed along the door panels. See figure 11-10.
The center outlet on the instrument panel is for air conditioning only, and is adjustable to direct cooled air to either front or rear compartments.
In 1956 outside air is used exclusively for heating when an air conditioner is not installed. Recirculated air, along with outside air is used when an air conditioner is installed. A fixed orifice in the evaporator case proportions the outside air to total air that is to be air conditioned. The right outside air vent valve is automatically opened to allow recirculation when the air conditioning unit is operating.
A spring loaded pressure relief valve in the right outside air vent valve is necessary to prevent cold air from entering the car when the heater blower is off. This valve is used only when air conditioning unit is installed, permitting air to recirculate and enter the heating core when the heater blower is on.
In 1956 the same outside air ventilation system is used as in 1955.