Chevrolet 70 Series 1970, Service Manual

Page: 154 / 841

CAB AND BODY MOUNTINGS 1-123
P. O . A . OR
SUCTION THROTTLING VALVE
X
EVAPORATOR
[
COMPRESSOR
________
/
TO
"CONDENSER
10 HI
J-5725-02
D RU M .
I 1 ! ‘i i
J-6272-01
FROM RECEIVER-DEHYDRATOR
K 3 7 "
REFRIGERANT-12
Figure 23—Hook Up of Gauges and Charging Equipment
p s ig ). For higher le v e ls , se t valve K-lb. p e r - s q .-
in. higher for each
1 ,0 0 0
feet of elevation.
14. R em ove charging m anifold gauge s e t, te st
fitting gauge, and in sta ll the fitting cap s.
DEPRESSURIZING THE SYSTEM
Any tim e the sy ste m is to be opened, it must
fir s t be d e p ressu r ized . D e p r e ssu r iz e the sy ste m
a s follow s:
NOTE: In stall gauge se t to co m p resso r gauge
fittin g s (fig.
2 2
) (sam e connections a s shown in
fig u r e s
2 1
and
2 2
).
1. R em ove cap s from gauge fittin gs at com ­
p r e s s o r .
2. With both v a lv e s on the m anifold gauge se t
(J-5725-04) c lo se d (c lo ck w ise), attach m anifold
h o se s to co m p r e sso r fittin g s, using (J-5420) Schra­
der valve adapter at the suction gauge fitting and
(J-9459) Schrader valve adapter at the d isch arge
gauge fittin g.
3. C rack open the high p r e s s u r e valve on man­
ifold gauge s e t to allow slo w escap e of refrigeran t
from the sy ste m through the m anifold gauge s e t
and out the cen ter fitting and h o se. (P la ce end of
h o se in clean container.) If o il d rips from the hose
into the container, refrigeran t i s escaping too
rapidly.
4. When h issin g c e a s e s (indicating a ll r e fr ig ­
erant has escaped) c lo s e v a lv es on m anifold gauge
s e t by turning valve clock w ise.
EVACUATING THE SYSTEM
When the refrig era tio n sy ste m is d e p r e ssu r ­
iz e d and opened for s e r v ic e , so m e a ir w ill enter
the lin e s r e g a r d le ss of how quickly the openings
a r e capped. In order to rem ove th is a ir and as
much a s p o ssib le o f the m o istu re it contains, the
com p lete sy ste m m ust be "evacuated." Evacuating
i s m erely the p r o c e s s of rem oving a ll a ir from the
sy ste m , thereby creatin g a vacuum in the sy stem .
CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL