Bryant R-22 Application Manual And Service Manual page 44

OUTDOOR TEMP (°F)
55
60
65
70
75
80
85
90
95
100
105
110
115
Where a dash appears, do not attempt to charge system under these conditions or refrigerant slugging may occur.
SUPERHEAT TEMP
(°F)
0
2
4
6
8
10
12
14
16
18
20
22
24
26
28
30
32
34
36
38
40
a TXV, the subcooling method must be used. Heat pumps must be
operating in the cooling mode. To charge by superheat, a service
technician needs an accurate superheat thermocouple or
thermistor-type thermometer, a sling psychrometer, and a gage
manifold. Do not use mercury or small-dial-type thermometers as
they are not adequate for this type of measurement. Then use 1 of
the following procedures:
SUPERHEAT CHARGING METHOD
1. Operate a unit a minimum of 10 minutes before checking
charge.
2. Measure vapor pressure by attaching a gage to vapor
valve-service port.
3. Measure vapor-line temperature by attaching a service
thermometer to unit vapor line near vapor valve. On a heat
pump, attach to the suction tube between the accumulator
and the compressor. Insulate thermometer for accurate
readings.
4. Measure outdoor-air, dry-bulb temperature with a second
thermometer.
TABLE 21—SUPERHEAT CHARGING TABLE
INDOOR COIL ENTERING AIR TEMP (°F WET BULB)
50 52 54 56
9 12 14 17
7 10 12 15
— 6 10 13
— — 7 10
— — — 6
— — — —
— — — —
— — — —
— — — —
— — — —
— — — —
— — — —
— — — —
TABLE 22—REQUIRED VAPOR TEMPERATURE (°F)
61.5 64.2 67.1
35 37 39
37 39 41
39 41 43
41 43 45
43 45 47
45 47 49
47 49 51
49 51 53
51 53 55
53 55 57
55 57 59
57 59 61
59 61 63
61 63 65
63 65 67
65 67 69
67 69 71
69 71 73
71 73 75
73 75 77
75 77 79
58 60 62 64
20 23 26 29
18 21 24 27
16 19 21 24
13 16 19 21
9 12 15 18
5 8 12 15
— — 8 11
— — 5 9
— — — 6
— — — —
— — — —
— — — —
— — — —
VAPOR PRESSURE AT SERVICE PORT (PSIG)
70.0 73.0
41 43
43 45
45 47
47 49
49 51
51 53
53 55
55 57
57 59
59 61
61 63
63 65
65 67
67 69
69 71
71 73
73 75
75 77
77 79
79 81
81 83
5. Measure indoor-air (entering indoor coil), wet-bulb tem-
perature with a sling psychrometer.
6. Locate outdoor temperature and evaporator entering air
wet-bulb temperature in Table 21. At this intersection note
the superheat.
7. Locate superheat temperature located in previous step and
vapor pressure in Table 22. At this intersection note
vapor-line temperature.
8. If unit has a higher vapor-line temperature than charted
temperature, add refrigerant until charted temperature is
reached.
9. If unit has a lower vapor-line temperature than charted
temperature, bleed refrigerant until charted temperature is
reached.
10. If outdoor-air temperature or pressure at vapor valve
changes, charge to new vapor-line temperature indicated on
chart.
SUBCOOLING CHARGING METHOD
1. Operate unit a minimum of 15 minutes before checking
charge.
—44—
66 68 70 72
32 35 37 40
30 33 35 38
27 30 33 36
24 27 30 33
21 24 28 31
18 21 25 28
15 19 22 26
13 16 20 24
10 14 18 22
8 12 15 20
5 9 13 17
— 6 11 15
— — 8 14
76.0 79.2 82.4
45 47 49
47 49 51
49 51 53
51 53 55
53 55 57
55 57 59
57 59 61
59 61 63
61 63 65
63 65 67
65 67 69
67 69 71
69 71 73
71 73 75
73 75 77
75 77 79
77 79 81
79 81 83
81 83 85
83 85 87
85 87 89
74 76
42 45
40 43
38 41
36 39
34 37
31 35
30 33
27 31
25 29
23 27
22 26
20 25
18 23
85.7
51
53
55
57
59
61
63
65
67
69
71
73
75
77
79
81
83
85
87
89
91