GMC 1986 P-Truck Service Manual page 69

1B-6 AIR CONDITIONING
33. Accum ulator
130. Exapansion Tube (Orifice)
124. Evaporator
600. Compressor
601. Condenser
604. Pressure Cycling Switch
605. Oil Bleed Hole
606. Dessicant Bag
REFRIGERANT
PRESSURE - TEMPERATURE
RELATIONSHIP
The table below indicates the pressure of Refriger­
ant-12 at various temperatures. For instance, a
drum of Refrigerant at a temperature of 26.6°C
(80°F) will have a pressure of 579.9 kPa (84.1 psi).
If it is heated to 51.6°C (125°F), the pressure will
increase to 1 154.9 kPa (167.5 psi). It also can be
used conversely to determine the temperature at
which Refrigerant - 12 boils under various pres­
sures. For example, at a pressure of 207.5 kPa
(30.1 psi), Refrigerant - 12 boils at 0°C (32°F).
Figure 7—Pressure Temperature Relationship of Refrigerant-12
L.
M.
and leaves as high pressure liquid.
N.
tor, reducing its pressure and warm blower air
across evaporator core causes boiling o ff of liquid
O.
Figure 6—CCOT A/C System Components
-
12
°C
-29.8
-28.8
-23.3
-20.5
-17.7
-15.0
-12.2
- 9.4
- 6.6
- 3.8
- 1.1
1.6
4.4
7.2
10.0
" HPV" - High pressure vapor leaving compressor.
" HPL" - Vapor is cooled down by condenser air flow
" LPL" - O rifice meters the liquid R-12 into evapora-.
into vapor.
" LPV" - Leaves evaporator as low pressure vapor
and returns with the small amount of . . .
" LPV/lpi" - Low pressure liquid that didn't boil o ff
com pletely back to the compressor to be com ­
pressed again.
°F kPa
PSIG
21.7 0 Atmos­
pheric
Pressure
-20 16.5 2.4
-10
31.0 4.5
-5 46.9 6.8
0 63.4 9.2
5 81.4 11.8
10 101.4 14.7
15 17.7
122.0
20 145.5 21.1
25 169.6 24.6
30
196.5 28.5
0 32 207.5 30.1
35 224.8 32.6
40 255.1 37.0
45 287.5 41.7
50 322.0 46.7
606
F-00075
°C °F kPa PSIG
12.7
55 358.5 52.0
15.5 60 397.8 57.7
18.3 65 439.2 63.7
21.1 70 482.7 70.1
23.8 75 530.2 76.9
26.6 80 579.9 84.1
29.4 85 632.3 91.7
32.2 90 686.7
99.6
35.0 95 745.3 108.1
37.7 100 806.0 116.9
40.5 105 870.2 126.2
43.3 110 937.7 136.0
46.1 115 1010.1 146.5
48.8 120 1083.2 157.1
51.6 125 1154.9 167.5
54.4
130 1234.2 179.0
60.0 140 1410.0 204.5
F-00177