Chevrolet 10 Series 1970 Service Manual page 41

EVAPORATOR
PRESSURE
CONTROL
VALVE
(P .O .A .)
BLOWER ASSEMBLY
HEATER HOSES
UNDERDASH
FORWARD
TO DEFROSTER
OUTLETS
FLOOR OUTLET
c o o le r a ir, m oving the le v e r tow ard C O O L w ill send
so m e a ir through the evap orator co re (in operative when
the O U T L E T S le v e r is set fo r heater operation) which in
e ffe c t bypasses the heater core
output.
A ir Control Lever
When the control is p ro p e rly adjusted, fu ll le ft position
("IN S ID E ") w ill supply 100% recircu la ted inside a ir, and
m ovin g the le v e r to the word "O U T S ID E " w ill supply
100% outside a ir to the system .
t r o ls a vacuum switch which in turn actuates an a ir inlet
door in the plenum below the a ir inlet g r ille and a r e c ir ­
culating a ir door in the kick pad.
vacuum also clo ses the Hot W a ter Shut O ff V a lve, p r e ­
venting coolant flo w through the heater core.
Defroster
A s the A ir control knob is m oved to the righ t fro m the
"O U T S ID E " position toward the word D EFRO STER the
d iv e r te r door within the distribu tor duct m oves to send a
portion of the a irflo w to the d e fro s te r ducts.
position of the A IR knob, as indicated on the panel, is the
D E -IC E position which sends the total a irflo w to the
d e fro s te r ducts.
EVAPORATOR
CORE ASSEMBLY
EXPANSION
VALVE
WATER
VALVE
F ig . 18—Four-Season System C om ponents — 10-30 Series Shown
resu lting in le s s heat
L e v e r m ovem ent con­
In the full le ft position,
Fu ll " r ig h t"
HEATER AND AIR CONDITIONING 1A-11
UNDERHOOD FORWARD
MUFFLER COMPRESSOR
^ ASSEMBLY
HEATER CORE
A N D DISTRIBUTOR
ASSEMBLY
RIGHT DASH OUTLET
TO CENTER DASH OUTLET
TO LEFT DASH OUTLET
Fan Switch
The fan switch controls the operation of the th ree
speed b low er m otor.
ROOF M O UNTED SYSTEM
The Roof-M ounted System is a v a ila b le fo r C IO -20 s e rie s
Suburban Trucks.
Th is system is s im ila r to the Four-Season System in
placem en t of the com p ressor, condenser and r e c e iv e r -
dehydrator (fig. 19). It d iffe rs fro m the Four-Season
System in that it:
1. O perates independently of the heater system .
2. O perates on re circu la ted (inside) a ir only.
3. U tiliz e s a th erm ostatic switch instead of an evapora­
to r control (P O A ) va lve to control outlet a ir tem p er­
ature.
The roof-m ounted system incorporates a b low er evap­
o ra to r unit which is mounted to the inner ro of panel at the
r e a r of the veh icle. An overhead central a ir distribu tor
duct, which contains adjustable outlets, extends forw a rd
fro m the b lo w er-e va p o ra to r unit to the windshield header
panel. The re frig e ra n t lin es are routed fro m the engine
com partm ent to the b lo w er-ev a p o ra to r unit between the
CONDENSER
RECEIVER-
DEHYDRATOR
CHEVROLET TRUCK SERVICE MANUAL