Perform Ance D A T - Chevrolet 10 Series 1970 Service Manual

F ig . 28—Compressor C o n n e c to r B lock — T yp ica l
com pare the perform an ce of the system being tested with
the standards below:
1. D oors and windows closed.
shade.)
2. Hood up and engine exhaust suitably ventilated.
3. V eh icle in N E U T R A L with engine running at 2000 rpm.
4. A ir Conditioning controls set fo r -
• Maximum cooling.
Four-Season System
and tem perature le v e r at " C old ."
GM C h evrolet System - Right knob at " C ity ."
• High b low er speed.
5. Gauge set installed.
6. System settled out (run-in approxim ately 10 minutes).
7. A th erm om eter placed in fron t of veh icle g r ille and
another in the righ t hand dash outlet (Four-Season
and GM C h evrolet System s) o r right re a r outlet
(Roof-M ounted System s).
PERFORMANCE DATA
The follow in g P e rfo rm a n c e Data define norm al op era ­
tion of the system under the above conditions.
(V eh icle inside o r in
- Upper le v e r on "In s id e "
R ela tive
HEATER AND AIR CONDITIONING 1A-19
hum idity does not appear in the tables because a fte r run­
ning the p re sc rib e d length of tim e on re circ u la te d a ir
and maximum cooling, the rela tive humidity of the a ir
passing o v e r the evaporator core w ill rem ain at approx­
im a tely 35% to 40% re g a rd le s s of the ambient tem pera­
ture o r humidity.
Should e x c essive head p ressu res be encountered at
h igher ambient tem peratu res, an 18" fan placed in front
o f the veh icle and blowing into the condenser w ill p rovid e
the ex tra circu lation of a ir needed to bring the p ressu res
to within the lim its specified.
NOTE: H igher tem peratures
w ill occur at higher ambient tem peratu res.
areas of high humidity it is p ossib le to have
therm om eter and gauge readings approach but
not reach the figu res listed in the perform an ce
tables and s till have a sa tisfa ctory operating
unit. H ow ever, it is im portant to rem em b er that
low p ressu re has a d ire c t relationship to nozzle
outlet tem peratu re. If p ressu re is too low, ic e
w ill gradually fo rm on the evaporator fins, r e ­
strictin g a irflo w into the passenger a rea and
resu ltin g in insu fficien t o r no cooling.
Four-Season A ir Conditioning
(R e frig e ra n t Charge - 3 Lbs. - 4 O z.)
T em p era tu re of
A ir Entering
Condenser
Engine rpm
C om p ressor Head 145-
P re s s u re 155
E vap orator P re s s u re
at P O A See Chart Under E vaporator
D isch arge A ir 38-
T em p, at Right 41
Hand Outlet
Roof M ounted A ir Conditioning
(R e frig e ra n t Charge - 4 lb s .- 8 o z.)
T em p era tu re of
A ir Entering 70°
Condenser
Engine rpm
155-
C o m p resso r
Head P r e s s u r e * 165
Suction P r e s ­
10
su re p si*
D isch arge A ir 37-
Tem p era tu re* 44
and p ressu res
In
100° 110° 120°
2000
185- 200- 215- 255- 285-
195 210 225 265 295
Dependent Upon Altitude
C ontrol V a lve (PO A )
48-
38- 40- 41- 43-
41 43 44 46 51
110°
80° 90° 100° 120°
2000
165- 175- 200- 240- 275-
175 185 285
240 250
10 10 10 14 18
37- 38- 41- 46- 49-
44 45 48 53 56
CHEVROLET TRUCK SERVICE MANUAL