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SUBCOOLING
1. THE DIAGNOSTIC SCREEN ON THE THERMOSTAT OR OUTDOOR CONTROL 7-SEGMENT DISPLAY WILL SHOW INDOOR AND
OUTDOOR MOTOR CFMS OR RPMS.
2. MEASURE OUTDOOR AMBIENT TEMPERATURE.
3. CONNECT GAUGE SET.
4. CHECK LIQUID AND VAPOR LINE PRESSURES. COMPARE PRESSURES WITH COOLING MODE NORMAL OPERATING
PRESSURES IN THE APPLICABLE CHARGING STICKER, NORMAL OPERATING PRESSURES AT MAXIMUM CAPACITY.
NOTE
DIFFERENCES MAY MEAN IMPROPER CHARGE OR OTHER SYSTEM PROBLEM.
5. SET THERMOSTAT FOR HEAT/COOL DEMAND, DEPENDING ON MODE BEING USED:
USE
USING COOLING MODE
COOLING
MODE
SUBCOOLING VALUES (MAXIMUM / 100% CAPACITY) IN APPLICABLE CHARGING STICKER ARE BASED ON 70 TO
80°F (21-27°C) INDOOR RETURN AIR TEMPERATURE; IF NECESSARY, OPERATE HEATING TO REACH THAT
60ºF
TEMPERATURE RANGE; THEN SET THE INITIAL COOLING DEMAND AT MAXIMUM CAPACITY. THE PREFERRED METHOD IS
(15ºC)
TO USE THE "CHARGE MODE" JUMPER ON THE OUTDOOR CONTROL. SEE CHARGE MODE JUMPER SECTION ON PAGE 80.
USE
WHEN PRESSURES HAVE STABILIZED, CONTINUE WITH STEP 6.
HEATING
MODE
6. READ THE LIQUID LINE TEMPERATURE; RECORD IN THE LIQº SPACE.
7. READ THE LIQUID LINE PRESSURE; THEN FIND ITS CORRESPONDING TEMPERATURE IN THE TEMPERATURE/ PRESSURE
CHART LISTED IN THE APPLICABLE CHARGING STICKER AND RECORD IT IN THE SATº SPACE.
8. SUBTRACT LIQº TEMPERATURE FROM SATº TEMPERATURE TO DETERMINE SUBCOOLING; RECORD IT IN SCº SPACE.
9. COMPARE SCº RESULTS WITH APPLICABLE CHARGING STICKER, BEING SURE TO NOTE ANY ADDITIONAL CHARGE FOR
LINE SET AND/OR MATCH-UP.
10. IF SUBCOOLING VALUE IS GREATER THAN SHOWN IN APPLICABLE CHARGING STICKER FOR THE APPLICABLE UNIT,
REMOVE REFRIGERANT; IF LESS THAN SHOWN, ADD REFRIGERANT.
SATº
11. IF REFRIGERANT IS ADDED OR REMOVED, REPEAT STEPS 6 THROUGH 10 TO VERIFY CHARGE.
LIQº –
12. DISCONNECT GAUGE SET AND RE-INSTALL BOTH THE LIQUID AND SUCTION SERVICE VALVE CAPS.
SCº
=
Figure 53. Using HFC-410A Subcooling Method - High Speed (High Capacity)
°F
Psig
°F
Psig
32
100.8
48
137.1
33
34
105.0
50
142.2
35
107.1
51
144.8
36
52
147.4
37
111.4
53
150.1
38
113.6
54
152.8
115.8
55
155.5
40
118.0
56
158.2
41
120.3
57
161.0
42
122.6
58
43
125.0
166.7
44
127.3
60
45
61
172.6
46
132.2
62
175.4
47
134.6
CHARGING METHOD
-
THE REFERENCE TABLE IS A GENERAL GUIDE. EXPECT MINOR PRESSURE VARIATIONS. SIGNIFICANT
— WHEN THE OUTDOOR AMBIENT TEMPERATURE IS 60°F (15°C) AND ABOVE. TARGET
°F
Psig
°F
63
178.5
231.6
64
181.6
80
235.3
65
184.3
81
66
187.7
82
242.7
67
83
246.5
68
84
250.3
85
254.1
70
200.6
86
258.0
71
87
262.0
72
207.2
88
266.0
73
210.6
270.0
74
214.0
274.1
75
217.4
278.2
76
282.3
77
224.4
286.5
78
228.0
Table 32. HFC-410A Temperature (°F) - Pressure (Psig)
(All charging MUST be performed while system is operating
either at maximum speed or 100% demand.)
Psig
°F
Psig
°F
110
111
112
303.8
113
308.2
114
312.7
115
100
317.2
116
101
321.8
117
102
326.4
118
103
331.0
104
335.7
120
105
340.5
121
106
345.3
122
107
350.1
123
108
355.0
124
360.0
Psig
°F
Psig
365.0
125
141
370.0
126
451.8
142
375.1
127
457.6
143
380.2
128
463.5
144
385.4
145
130
475.6
146
131
481.6
147
401.3
132
487.8
148
406.7
133
412.2
134
500.2
150
417.7
135
506.5
151
423.2
136
152
428.8
137
153
434.5
138
525.8
154
440.2
532.4
155
140
°F
Psig
545.6
552.3
572.8
586.8
601.0
608.1
615.4
622.7
630.1
637.5
645.0
31-5000750 Rev. 1
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