Lennox EL23XCV Series Manual page 79

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 49. Using HFC-410A Subcooling Method - High Speed (High Capacity)
°F Psig °F Psig
32 100.8 48 137.1
33 102.9 49 139.6
34 105.0 50 142.2
35 107.1 51 144.8
36 109.2 52 147.4
37 111.4 53 150.1
38 113.6 54 152.8
39 115.8 55 155.5
40 118.0 56 158.2
41 120.3 57 161.0
42 122.6 58 163.9
43 125.0 59 166.7
44 127.3 60 169.6
45 129.7 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
TABLE 21. HFC-410A Temperature (°F) - Pressure (Psig)
.
°F Psig °F Psig
63 178.5 79 231.6
64 181.6 80 235.3
65 184.3 81 239.0
66 187.7 82 242.7
67 190.9 83 246.5
68 194.1 84 250.3
69 197.3 85 254.1
70 200.6 86 258.0
71 203.9 87 262.0
72 207.2 88 266.0
73 210.6 89 270.0
74 214.0 90 274.1
75 217.4 91 278.2
76 220.9 92 282.3
77 224.4 93 286.5
78 228.0
(All charging MUST be performed while system is operating
either at maximum speed or 100% demand.)
°F Psig °F
94 290.8 110
95 295.1 111
96 299.4 112
97 303.8 113
98 308.2 114
99 312.7 115
100 317.2 116
101 321.8 117
102 326.4 118
103 331.0 119
104 335.7 120
105 340.5 121
106 345.3 122
107 350.1 123
108 355.0 124
109 360.0
Page 79
Psig °F Psig °F
365.0 141
125 445.9
370.0 126 451.8 142
375.1 127 457.6 143
380.2 128 463.5 144
385.4 129 469.5 145
390.7 130 475.6 146
396.0 131 481.6 147
401.3 132 487.8 148
406.7 133 494.0 149
412.2 134 500.2 150
417.7 135 506.5 151
423.2 136 512.9 152
428.8 137 519.3 153
434.5 138 525.8 154
440.2 139 532.4 155
140 539.0
Psig
545.6
552.3
559.1
565.9
572.8
579.8
586.8
593.8
601.0
608.1
615.4
622.7
630.1
637.5
645.0