TM 9-4110-255-14
5-16. REFRIGERANT SYSTEM PRESSURE CHECK.
This task covers:
a. Testing
INITIAL SETUP
Equipment Conditions:
Service manifold installed (para 5-9).
Testing.
(1) Check that all four service manifold valves are closed.
(2) Service manifold compound and pressure gages should indicate the same pressure. Check the reading
with the appropriate column in Table 5-1. If the system is even partially charged, the pressure should be
approximately equal to that shown in the table for the appropriate ambient temperature. If the pressure is
considerably less than shown in the table, the system does not contain enough refrigerant to continue the
pressure check. Leak test the refrigeration system (para 5-13).
Table 5-1. Pressure Temperature Relationship of Saturated Refrigerant R-134a
Temperature
Pressure
Temperature
Pressure
kg/cm2
kg/cm2
Deg F
Deg C
psia
Deg F
Deg C
psia
-20
-28.88
12.95
5.87
60
15.55
72.09
32.69
-18
-27.77
13.63
6.18
62
16.66
74.69
33.87
-16
-26.66
14.35
6.50
64
17.77
77.36
35.08
-14
-25.55
15.09
6.84
66
18.88
80.09
36.32
-12
-24.44
15.87
7.19
68
20.00
82.90
37.60
-10
-23.33
16.67
7.56
70
21.11
85.79
38.91
-8
-22.22
17.51
7.94
72
22.22
88.75
40.25
-6
-21.11
18.38
8.33
74
23.33
91.79
41.63
-4
-20.00
19.29
8.74
76
24.44
94.90
43.04
-2
-18.88
20.23
9.17
78
25.55
98.09
44.49
0
-17.77
21.20
9.61
80
26.66
101.37
45.98
2
-16.66
22.22
10.07
82
27.77
104.73
47.50
4
-15.55
23.27
10.55
84
28.88
108.16
49.06
6
-14.44
24.35
11.04
86
30.00
111.69
50.66
8
-13.33
25.48
11.55
88
31.11
115.30
52.16
10
-12.22
26.65
12.08
90
32.22
118.99
53.97
12
-11.11
27.86
12.63
92
33.33
122.78
55.69
14
-10.00
29.11
13.20
94
34.44
126.65
57.44
16
-8.88
30.41
13.79
96
35.55
130.62
59.24
18
-7.77
31.75
14.40
98
36.66
134.68
61.08
20
-6.66
33.14
15.03
100
37.77
138 83
62.59
5-30
