7
Run the remote on low stage cooling for 10 minutes until refrig-
erant pressures stabilize. Use the following guidelines and meth-
ods to check unit operation and ensure that the refrigerant
charge is within limits. Charge the unit on low stage.
1. Purge gauge lines. Connect service gauge manifold to
base-valve service ports.
2. Temporarily install a thermometer on the liquid line at
the liquid line service valve and 4-6" from the compressor
on the suction line. Ensure the thermometer makes
adequate contact and is insulated for best possible
readings. Use liquid line temperature to determine sub-
cooling and vapor temperature to determine superheat.
3. Check subcooling and superheat. Systems with TXV
application should have a subcooling of 5 to 7ºF and
superheat of 7 to 9 ºF.
a.
If subcooling and superheat are low,
adjust
TXV to 7
to 9 ºF superheat, then check subcooling.
NOTE:
To adjust superheat, turn the valve stem
clockwise to increase and counter clockwise to de-
crease.
b.
If subcooling is low and superheat is high,
add
charge
to raise subcooling to 5 to 7 ºF then check super-
heat.
c.
If subcooling and superheat are high,
adjust
TXV
valve to 7 to 9 ºF superheat, then check subcooling.
d.
If subcooling is high and superheat is low,
adjust
TXV valve to 7 to 9 ºF superheat and
remove
charge
to lower the subcooling to 5 to 7 ºF.
NOTE:
Do
NOT
adjust the charge based on suction
pressure unless there is a gross undercharge.
4. Disconnect manifold set, installation is complete.
NOTE:
Check the Schrader ports for leaks and tighten valve
cores if necessary. Install caps finger-tight.
SUPERHEAT FORMULA =
SUCT. LINE TEMP. - SAT. SUCT. TEMP.
LIQUID PRESSURE
PSIG
R-22
R-410A
200
101
70
210
105
73
220
108
76
225
110
78
235
113
80
245
116
83
255
119
85
265
121
88
275
124
90
285
127
92
295
130
95
305
133
97
325
137
101
355
144
108
375
148
112
405
155
118
415
157
119
425
n/a
121
435
n/a
123
445
n/a
125
475
n/a
130
500
n/a
134
525
n/a
138
550
n/a
142
575
n/a
145
600
n/a
149
625
n/a
152
SATURATED LIQUID PR ESSU RE
TEMPER ATU RE CHART
SATURATED LIQUID
TEMPERATURE ºF
SUCTION PRESSURE
PSIG
R-22
R-410A
50
26
1
52
28
3
54
29
4
56
31
6
58
32
7
60
34
8
62
35
10
64
37
11
66
38
13
68
40
14
70
41
15
72
42
16
74
44
17
76
45
19
78
46
20
80
48
21
85
50
24
90
53
26
95
56
29
100
59
31
110
64
36
120
69
41
130
73
45
140
78
49
150
83
53
160
86
56
170
90
60
SATURATED SUCTION PRESSURE
TEMPERATURE CHART
SATURATED SUCTION
TEMPERATURE ºF
Содержание CONDENSING UNITAIR CONDITIONING
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