Bryant 591B User Manual
Page 7
EXAMPLE:
To calculate additional charge requried for a 25-ft line set:
25 ft - 15 ft = 10 ft X 0.6 oz/ft = 6 oz of additional charge.
B.
COOLING ONLY PROCEDURE
UNITS WITH COOLING MODE PURON® TXV
Units installed with cooling mode TXV require charging by the
subcooling method.
1. Operate unit a minimum of 10 minutes before checking
charge.
2. Measure liquid service valve pressure by attaching an
accurate gage to service port.
3. Measure liquid line temperature by attaching an accurate
thermistor type or electronic thermometer to liquid line near
outdoor coil.
4. Refer to unit rating plate for required subcooling tempera-
ture.
5. Refer to Table 3. Find the point where required subcooling
temperature intersects measured liquid service valve pres-
sure.
6. To obtain required subcooling temperature at a specific
liquid line pressure, add refrigerant if liquid line tempera-
ture is higher than indicated or reclaim refrigerant if
temperature is lower. Allow a tolerance of ± 3°F.
UNITS WITH INDOOR PISTONS
Units installed with indoor pistons require charging by the super-
heat method.
The following procedure is valid when indoor airflow is within ±
21 percent of its rated CFM.
1. Operate unit a minimum of 10 minutes before checking
charge.
2. Measure suction pressure by attaching an accurate gage to
suction valve service port.
3. Measure suction temperature by attaching an accurate
thermistor type or electronic thermometer to suction line at
service valve.
4. Measure outdoor air dry-bulb temperature with thermom-
eter.
5. Measure indoor air (entering indoor coil) wet-bulb tempera-
ture with a sling psychrometer.
TABLE 3—REQUIRED LIQUID-LINE TEMPERATURE (°F)
LIQUID
PRESSURE AT
SERVICE VALVE
(PSIG)
REQUIRED SUBCOOLING
TEMPERATURE
(°F)
8
10
12
14
16
18
189
58
56
54
52
50
48
195
60
58
56
54
52
50
202
62
60
58
56
54
52
208
64
62
60
58
56
54
215
66
64
62
60
58
56
222
68
66
64
62
60
58
229
70
68
66
64
62
60
236
72
70
68
66
64
62
243
74
72
70
68
66
64
251
76
74
72
70
68
66
259
78
76
74
72
70
68
266
80
78
76
74
72
70
274
82
80
78
76
74
72
283
84
82
80
78
76
74
291
86
84
82
80
78
76
299
88
86
84
82
80
78
308
90
88
86
84
82
80
317
92
90
88
86
84
82
326
94
92
90
88
86
84
335
96
94
92
90
88
86
345
98
96
94
92
90
88
354
100
98
96
94
92
90
364
102
100
98
96
94
92
374
104
102
100
98
96
94
384
106
104
102
100
98
96
395
108
106
104
102
100
98
406
110
108
106
104
102
100
416
112
110
108
106
104
102
427
114
112
110
108
106
104
439
116
114
112
110
108
106
450
118
116
114
112
110
108
462
120
118
116
114
112
110
474
122
120
118
116
114
112
486
124
122
120
118
116
114
499
126
124
122
120
118
116
511
128
126
124
122
120
118
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