5. If no leak is found during initial start-up procedures, com-
plete the transfer of refrigerant gas (see Pumpout and
Refrigerant Transfer Procedures section, page 64.)
6. If no leak is found after a retest:
a. Transfer the refrigerant to the utility vessel or other
storage tank and perform a standing vacuum test as
outlined in the Standing Vacuum Test section, this page.
b. If the machine fails this test, check for large leaks
(Step 2b).
c. Dehydrate the machine if it passes the standing vacuum
test. Follow the procedure in the Machine Dehydra-
tion section. Charge machine with refrigerant (see
Pumpout and Refrigerant Transfer Procedures section,
page 64.)
7. If a leak is found, pump the refrigerant back into the util-
ity vessel or other storage tank.
8. Transfer the refrigerant until machine pressure is at
18 in. Hg (41 kPa absolute).
9. Repair the leak and repeat the procedure, beginning from
Step 2g to ensure a leaktight repair. (If machine is opened
to the atmosphere for an extended period, evacuate it be-
fore repeating leak test.)
Standing Vacuum Test — When performing the stand-
ing vacuum test, or machine dehydration, use a manometer
or a wet bulb indicator. Dial gages cannot indicate the small
amount of acceptable leakage during a short period of time.
1. Attach an absolute pressure manometer or wet bulb in-
dicator to the machine.
2. Evacuate the vessel (see Pumpout and Refrigerant Trans-
fer Procedures section, page 64) to at least 18 in. Hg vac,
ref 30-in. bar (41 kPa), using a vacuum pump or the pump-
out unit.
3. Valve off the pump to hold the vacuum and record the
manometer or indicator reading.
4. a. If the leakage rate is less than 0.05 in. Hg (.17 kPa) in
24 hours, the machine is sufficiently tight.
b. If the leakage rate exceeds 0.05 in. Hg (.17 kPa) in
24 hours, repressurize the vessel and test for leaks. If
refrigerant is available in the other vessel, pressurize
by following Steps 2-10 of Return Refrigerant To Nor-
mal Operating Conditions section, page 66. If not, use
nitrogen and a refrigerant tracer. Raise the vessel pres-
sure in increments until the leak is detected. If refrig-
erant is used, the maximum gas pressure is approxi-
mately 70 psig (483 kPa) at normal ambient temperature.
5. Repair leak, retest, and proceed with dehydration.
Table 5A — HFC-134a Pressure — Temperature (F)
TEMPERATURE (F) PRESSURE (psi)
0 6.50
2 7.52
4 8.60
6 9.66
8 10.79
10 11.96
12 13.17
14 14.42
16 15.72
18 17.06
20 18.45
22 19.88
24 21.37
26 22.90
28 24.48
30 26.11
32 27.80
34 29.53
36 31.32
38 33.17
40 35.08
42 37.04
44 39.06
46 41.14
48 43.28
50 45.48
52 47.74
54 50.07
56 52.47
58 54.93
60 57.46
62 60.06
64 62.73
66 65.47
68 68.29
70 71.18
72 74.14
74 77.18
76 80.30
78 83.49
80 86.17
82 90.13
84 93.57
86 97.09
88 100.70
90 104.40
92 108.18
94 112.06
96 116.02
98 120.08
100 124.23
102 128.47
104 132.81
106 137.25
108 141.79
110 146.43
112 151.17
114 156.01
116 160.96
118 166.01
120 171.17
122 176.45
124 181.83
126 187.32
128 192.93
130 198.66
132 204.50
134 210.47
136 216.55
138 222.76
140 229.09
49
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