Chevrolet 30 Series 1967 Service Manual page 30

HEATER AND AIR CONDITIONING 1A-2
pression formed in the toe board.
the air passes by a shut-off valve which is either closed
or fully open. The air then passes through the defroster
valve which directs the airflow to the floor outlet, to both
floor and defroster outlets, or to the defroster outlets.
Since temperature is adjusted by controlling airflow
through the core, the core is continuously supplied with
hot coolant while the engine is running.
temperature, and defroster controls are located on the
panel between the steering column and dash (fig. 4).
TILT CAB HEATER
The Tilt Cab Heater is mounted on the toe board inside
From the core housing
The blower, air,
the cab. Outside air flows through a grille in the front
end panel and across to the heater air inlet. A four lever
dash control regulates the fan speed, defroster, heater
core temperature, and airflow (fig.
defroster, and air valve operate similarly to the Deluxe
Air Heater. The Tilt Cab Heater temperature control,
however, regulates coolant flow through the heater core
via a thermostatic valve which is mounted on the core.
CONTROLS
DELUXE AIR HEATER
DEF Lever
Moving the DEF (defroster) lever to the right moves an
air deflector in the distributor duct which channels the
airflow partially or fully to the defroster air outlets.
AIR FAN Lever
When this lever is fully left, no air passes through the
system. Moving the lever to the right about one-third of
its travel opens the air door in the air distributor duct.
Moving the lever further to the right operates the three
speed blower switch.
HEAT Lever
When this lever is fully left, the temperature door in
the blower duct causes the airflow to bypass the heater
core. Moving the lever to the right moves the tempera­
ture door allowing some air to pass through the core and
some to bypass the core. With the lever fully right, all
air flowing through the system passes through the core.
CHEVY VAN HEATER
AIR Knob
Pulling the AIR knob will open an air shut-off door
located in the distributor duct. Air will not flow through
the system with the knob pushed in.
FAN-HEAT Knob
Pulling the FAN-HEAT knob fully out moves a deflector
which causes the entire airflow to pass through the heater
core. When the knob is fully in, the entire air-flow
passes around the heater core. Any intermediate position
of the knob allows some air to bypass the core and some
to pass through it in proportion to the knob setting.
Turning the knob operates the three speed blower switch.
DEFROSTER Knob
Pulling the DEFROSTER knob moves a deflector in the
air distributor which directs the airflow to the defroster
outlets. When the knob is fully in, all air is discharged
through the floor outlets. Intermediate positions of the
knob split the airflow between the floor and defroster
outlets in proportion to knob setting.
). The fan switch,
6
CHEVROLET TRUCK SERVICE MANUAL