Page 14
504954M 08/06
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 HFC−410A to
determine the saturation temperature for the liquid line
pressure reading. See table 4.
Table 4
HFC−410A Temperature (°F) − Pressure (Psig)
°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
4. Subtract the liquid line temperature from the saturation
temperature (according to the chart) to determine sub-
cooling.
(Saturation temperature − Liquid line tem-
perature = 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 HFC−410A refrigerant cylin-
der. It will be light maroon−colored. Refrigerant should
be added through the vapor line valve in the liquid
state.
NOTE − Some HFC−410A cylinders are equipped with a dip
tube that allows you to draw liquid refrigerant from the bot-
tom of the cylinder without turning the cylinder upside−
down. The cylinder will be marked if it is equipped with a dip
tube.
Table 5
Subcooling Values for Charging
Model Number
Second Stage (High Capacity)
Subcooling Values Conversion Temp. −
Liquid Line Temp.
°
F (
°
C)
HPXA16−024
11.0 + 1 (6 + .5)
HPXA16−036
8.5 + 1 (4.7 + .5)
HPXA16−048
7.5 + 1 (4.1 + .5)
HPXA16−060
7.0 + 1 (3.9 + .5)
Charge Using the Approach Method –
Outdoor Temperature > 65
F (18
C)
The following procedure is intended as a general guide and
is for use on expansion valve systems only. For best re-
sults, indoor temperature should be 70°F (21°C) to 80°F
(26°C). Monitor system pressures while charging.
1. Record outdoor ambient temperature using a digital
thermometer.
2. Attach high pressure gauge set and operate unit for
several minutes to allow system pressures to stabilize.
3. Compare stabilized pressures with those provided in
tables 6 and 7, Normal Operating Pressures."
IMPORTANT
Use tables 6 & 7 as a general guide when performing
maintenance checks. This is not a procedure for
charging the unit.
Minor variations in these pressures may be ex-
pected due to differences in installations. Signifi-
cant differences could mean that the system is not
properly charged or that a problem exists with some
component in the system.
Pressures higher than those listed indicate that the
system is overcharged. Pressures lower than those
listed indicate that the system is undercharged.
Continue to check adjusted charge using approach
values.
