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If weighing facilities are not available or if you are charging
the unit during warm weather, follow one of the other pro-
cedures outlined below.
Subcooling
Method
- Outdoor
Temperature
< 65°F (18°C)
When the outdoor ambient temperature
is below 65°F
(18°C), use the subcooling method to charge the unit. It
may be necessary to restrict air flow through the outdoor
coil to achieve pressures in the 325-375 psig (2240-2585
kPa) range--higher
pressures are necessary for checking
the charge. Block equal sections of air intake panels and
move obstructions sideways until the liquid pressure is in
the 325-375 psig (2240-2585 kPa) range. See figure 18.
Blocking
Outdoor
Coil
__
*Outdoor coil should be blocked one
_Y
I side at a time with cardboard
If [I
I or plastic sheet until proper testing
]),11
I .P rF:Su_.U:ied:
d r:nri___ho e v dn' '
)-...
CARDBOARD
OR PLASTIC SHEET
Figure
18
1. With the manifold gauge hose still on the liquid service
port and the unit operating stably, use a digital ther-
mometer to record the liquid line temperature.
2. At the same time, record the liquid line pressure reading.
3. Use a temperature/pressure
chart for R-410A (table 4)
to determine saturation temperature for the liquid line
pressure reading.
4. Subtract the liquid line temperature from the saturation
temperature
(from table 4) to determine subcooling.
(Saturation temp. - Liquid line temp. = Subcooling)
5. Compare the subcooling value with those in table 5. If
subcooling is greater than shown, recover some refrig-
erant. If subcooling is less than shown, add some re-
frigerant. Be aware of the R-410A refrigerant cylinder.
It will be light maroon-colored.
Refrigerant should be
added through the vapor line valve in the liquid state.
NOTE - Some R-410A cylinders are equipped with a
dip tube that allows you to draw liquid refrigerant from
the bottom of the cylinder without turning the cylinder
upside-down.
The cylinder
will be marked if it is
equipped with a dip tube.
Table 4
R-410A Temp.
(°F) - Pressure
(Psig) Chart
°F
Psig
°F
Psig
°F
Psig
°F
Psig
32
100.8
63
178.5
94
290.8
125
445.9
33
102.9
64
181.6
95
295.1
126
451.8
34
105.0
65
184.3
96
299.4
127
457.6
35
107.1
66
187.7
97
303.8
128
463.5
36
109.2
67
190.9
98
308.2
129
469.5
37
111.4
68
194.1
99
312.7
130
475.6
38
113.6
69
197.3
100
317.2
131
481.6
39
115.8
70
200.6
101
321.8
132
487.8
40
118.0
71
203.9
102
326.4
133
494.0
41
120.3
72
207.2
103
331.0
134
500.2
42
122.6
73
210.6
104
335.7
135
506.5
43
125.0
74
214.0
105
340.5
136
512.9
44
127.3
75
217.4
106
345.3
137
519.3
45
129.7
76
220.9
107
350.1
138
525.8
46
132.2
77
224.4
108
355.0
139
532.4
47
134.6
78
228.0
109
360.0
140
539.0
48
137.1
79
231.6
110
365.0
141
545.6
49
139.6
80
235.3
111
370.0
142
552.3
50
142.2
81
239.0
112
375.1
143
559.1
51
144.8
82
242.7
113
380.2
144
565.9
52
147.4
83
246.5
114
385.4
145
572.8
53
150.1
84
250.3
115
390.7
146
579.8
54
152.8
85
254.1
116
396.0
147
586.8
55
155.5
86
258.0
117
401.3
148
593.8
56
158.2
87
262.0
118
406.7
149
601.0
57
161.0
88
266.0
119
412.2
150
608.1
58
163.9
89
270.0
120
417.7
151
615.4
59
166.7
90
274.1
121
423.2
152
622.7
60
169.6
91
278.2
122
428.8
153
630.1
61
172.6
92
282.3
123
434.5
154
637.5
62
175.4
93
286.5
124
440.2
155
645.0
Table 5
Subcooling
Values
for Charging
Model
Number
SPA036
SPA048
SPA060
Second Stage (High Capacity)
Subcooling
Values Conversion
- Liquid Line Temp. °F (°C)
8.5 + 1 (4.7 + .5)
7.5 + 1 (4.1 + .5)
7.0 + 1 (3.9 + .5)
Temp.
504867M
06/06
Page 14
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