Buick LeSabre 1965 Service Manual page 758

ACCESSORIES
HEATER SYSTEM 1 1 - 2 5
CLAMP OUTLET HOSE
INLET HOSE
CLAMP
CLAMP
NIPPLE—
1 L
CLAMP
45000 SERIES-300 CU. INCH ENGINE
NIPPLE IN WATER MANIFOLD
WATER HOSE
CLAMP
WATER HOSE
46000 AND 48000 SERIES- 401 AND 425 CU. INCH ENGINE
Figure 11-31—Heater System Water Flow
the blower motor, (2) the heater
assembly which houses the tem-
perature door, the outside air
door, the defroster door, and also
the heater core, (3) and a heater-
defroster control assembly which
regulates the opening and closing
of the doors in the heater
assembly.
The flow of coolant through the
heater system is as shown in
Figure 11-31.
a. Description of Air Flow
The air flow begins at air intake
grille located on the cowl forward
of the windshield (see Figure
11-32). The outside air passes
through the air intake grille into
the cowl air chamber, and then
into the blower and air inlet as-
sembly. The air flows thru the
blower and to the h e a t e r
assembly.
At the heater assembly, the air
stream divides and may flow
through the h e a t e r core or
through the duct by-passing the
core. The regulation of the flow
of air at this point is controlled
by the temperature door. When
the door is fully closed, air flow
through heater core is blocked
and all air is forced to circulate
around the core. When the door
is fully open, the air stream
through the by-pass around the
core is blocked and all air is
forced through the heater core.
Intermediate positioning of the
door mixes heated and unheated
air in proportionate amounts.
After the air passes through or
around, or both through and
around the heater core, it flows
past the outside air door and is
directed to the defroster door.
When the defroster door is closed
all air is channeled to the front
floor area. When the defroster
door is fully open all air is ducted
to the defroster outlets. Inter-
mediate positioning of the de-
froster valve apportions air to
both the defroster and the floor.
Depending on how much heat is
being directed to the defroster
outlet, the balance of the air
stream will flow through the cen-
ter heater outlet ( s e e Figure
11-33) to the front floor area.
b. Description and Operation
of Heater System Controls
The heater system is regulated
by three control levers which
function as follows:
1. TEMPERATURE Lever - This
lever opens and closes the tem-
perature door thereby controlling
the amount of air either by-pass-
ing or flowing thru the heater
core. Moving of the lever to the
right opens door and diverts the
air thru the heater core propor-
tionate to the travel of the lever.
2. HEATER Lever - This lever
regulates the outside air door
and the defroster door of the
heater assembly. When the lever