Chevrolet 10 Series 1970, Service Manual

Page: 32 / 671

HEATER AND AIR CONDITIONING 1A-2
O U T S ID E A IR
INLET
FLO O R OUTLETS
F ig . 2 —T i l t C ab H e a te r S chem atic
r e c e iv in g its a irflo w fro m the cowl vent plenum chamber.
Engine coolant constantly flow s through the h eater core
during engine operation. H eater output is adjusted by
va ry in g the a irflo w and a ir tem perature through the s y s ­
tem . A dash mounted th ree le v e r control system is em ­
ployed. One le v e r con trols the h e a te r-d e fro s te r a ir
d e fle c to r. The second le v e r opens the a ir door and op­
e ra te s the th ree speed fan switch. The third le v e r o p e r­
ates a tem peratu re door which passes the a irflo w eith er
through the heater c o re , around the co re, o r p a rtia lly
through and p a rtia lly around the core.
TILT CAB HEATER
Th e T ilt Cab H eater is mounted on the toe board inside
the cab. Outside a ir flo w s through a g r ille in the fron t
end panel and a cross to the heater a ir in let (fig. 2). A
fo u r le v e r dash control regu lates the fan speed, de­
fr o s t e r , heater, co re tem peratu re, and a irflo w . The fan
sw itch , d e fro s te r, and a ir va lve operate s im ila r ly to the
D eluxe A ir H eater. The T ilt Cab H eater tem perature
co n tro l, h ow ever, regu lates coolant flo w through the
h ea ter co re v ia a th erm ostatic va lve which is mounted on
the c o re .
CONTROLS
DELUXE AIR HEATER
The deluxe a ir heater con trols are located in the center
o f the dash, b elow the ash tray. In operation, three
le v e r s con trol a ll heater operations (fig. 3).
DEF Lever
M oving the DEF (d e fro s te r) le v e r to the righ t m oves
an a ir d e fle c to r in the d istrib u tor duct which channels the
a ir flo w p a rtia lly o r fu lly to the d e fro s te r a ir outlets.
A IR -FA N Lever
When this le v e r is fu lly le ft, no a ir passes through the
system . M oving the le v e r to the right about on e-th ird of
its tr a v e l opens the a ir door in the a ir distribu tor duct.
M oving the le v e r fu rth er to the right operates the three
speed b low er switch.
HEAT Lever
When this le v e r is fu lly left, the tem perature door in
the b lo w er duct causes the a irflo w to bypass the heater
c o re . M oving the le v e r to the right m oves the tem p era ­
tu re door allow ing som e a ir to pass through the co re and
som e to bypass the core. W ith the le v e r fu lly right, all
a ir flow in g through the system passes through the core.
F ig . 3 — D e lu xe A ir H e a te r C o n tro l Panel
CHEVROLET TRUCK SERVICE MANUAL