Pontiac FIREBIRD 1972 Service Manual page 73

1A-14 1972 PONTIAC SERVICE MANUAL
OPERATIONAL TEST CHART
TEST CONDITIONS:
Hood
.................................................................................................................
.Raised
Front Doors
.............................................................................................................
Open
A/C Control Panel
Select Lever
.................................................................................................
A/C Mode
Blower Speed Switch
..............................................................................................
..HI
Temperature Lever..
........................................................................................
.Full Cold
Nozzles and Air Outlets.
...............................................................................................
.Open
Engine Speed
.....................................................................................................
.ZOO0 RPM
TEST READINGS:
*NOTE: These pressures are for engine with engine fan clutch engaged. With fan clutch disengaged, pressures
generally are 25-35 psi higher than shown here.
Ambient Air in Degrees F. (In
Auxiliary Fan Air Blast
Ahead of Condenser)
Air Quality
*Average Compressor Head
Pressure in PSI
Average P.O.A. Valve Pressure
@*PSI AT SEA LEVEL
Center Outlet Temperature in
Degrees F.
**NOTE: Interior pressure of the P.O.A. valve is isolated from exterior atmospheric pressure. As a result, the
controlling element (vacuum bellows) of the P.O.A. valve is able to operate independently
of
the effect of atmospheric
pressure. However, any gauge used to check the P.O.A. valve pressure will not be free {rom the effect of atmospheric
pressure. This altitude effect on the gauge must be taken into account when interpreting a reading. As the altitude
increases and atmospheric pressure goes down, the pressure reading on the gauge will go up.
The increase noted in the above readings will be approximately . 5 psi per 1,000 feet above sea level. For example at
90°F. in an arid climate at 2,000 feet above sea level, P.O.A. valve pressures would be 29 to 31 psi.
Fig. 1A-14 A/C Operational Test Chart
700
Arid
163
to
187
27.5
to
29.5
380
to
420
Humid
193
to
217
28.5
to
30.5
410
to
450
800
Arid
193
to
217
28
to
30
39O
to
430
Humid
223
to
247
29
to
31
43O
to
470
900
Arid
223
to
247
28
to
30
400
to
440
Humid
263
to
287
30
to
32
47O
to
510
1000
Arid
258
to
282
28
to
30
41°
to
450
1100
Humid
313
to
337
33
to
35
520
to
560
Arid
298
to
322
28.5
to
30.5
430
to
470
Humid
373
to
397
37.5
to
39.5
590
to
630