Lennox LGM102U - Subcooling Method for Charge Verification

Page 37
TABLE 14 581030-01
LGM/LCM102U Reheat
Outdoor
Coil
Entering
Air Temp
Circuit 1 Circuit 2
Dis
charge
+
10 psig
Suction
+
5 psig
Dis
charge
+
10 psig
Suction
+
5 psig
655 F 264 140 266 137
755 F 301 139 300 139
855 F 349 141 341 141
955 F 399 144 390 144
1055 F 450 146 440 147
1155 F 508 149 494 150
TABLE 15 581031-01
LGM/LCM120U No Reheat
Outdoor
Coil
Entering
Air Temp
Circuit 1 Circuit 2
Dis
charge
+
10 psig
Suction
+
5 psig
Dis
charge
+
10 psig
Suction
+
5 psig
655 F 258 132 263 131
755 F 296 137 302 133
855 F 337 139 344 135
955 F 383 141 389 137
1055 F 439 142 438 140
1155 F 490 145 494 143
TABLE 16 581032-01
LGM/LCM120U Reheat
Outdoor
Coil
Entering
Air Temp
Circuit 1 Circuit 2
Dis
charge
+10 psig
Suction
+
5 psig
Dis
charge
+10 psig
Suction
+
5 psig
655 F 272 131 255 133
755 F 309 135 294 135
855 F 350 138 335 137
955 F 396 139 381 139
1055 F 452 141 430 142
1155 F 503 144 485 145
TABLE 17 581033-01
LGM/LCM150U No Reheat
Outdoor
Coil
Entering
Air Temp
Circuit 1 Circuit 2
Dis
charge
+
10 psig
Suction
+
5 psig
Dis
charge
+
10 psig
Suction
+
5 psig
655 F 267 122 270 113
755 F 308 128 313 120
855 F 355 133 363 127
955 F 399 136 407 130
1055 F 448 139 456 132
1155 F 503 142 510 136
TABLE 18 581034-01
LGM/LCM150U Reheat
Outdoor
Coil
Entering
Air Temp
CIRCUIT 1 CIRCUIT 2
Dis
charge
+
10 psig
Suction
+
5 psig
Dis
charge
+
10 psig
Suction
+
5 psig
655 F 313 123 259 113
755 F 353 129 302 121
855 F 401 134 351 127
955 F 445 137 396 130
1055 F 493 140 445 133
1155 F 548 143 499 137
Charge Verification - Subcooling Method - AHRI Test
ing
1-
Attach gauge manifolds to discharge and suction lines. With
the economizer disabled, operate the unit in cooling mode
at high speed using the following mobile service app menu
path:
RTU MENU > SERVICE > COMPONENT TEST > COOLING
>COOL 4
2- Use the liquid line pressure and a PT chart to determine
the saturated liquid temperature.
3- Measure the liquid line temperature at the condenser
outlet.
Subcooling Temperature = Liquid Saturated Tempera
ture Minus Liquid Temperature.
4-
Refer to table 19 for subcooling temperatures. A subcooling
temperature greater than this value indicates an overcharge.
A subcooling temperature less than this value indicates an
undercharge.
TABLE 19
SUBCOOLING TEMPERATURE
Unit
Liquid Temp. Minus Ambient Temp.
1st Stage 2nd Stage
092
12°F + 1 (6.7°C +
0.5)
15°F + 1 (8.3°C + 0.5)
092 Reheat
17°F + 1 (9.4°C +
0.5)
15°F + 1 (8.3°C + 0.5)
102
11°F + 1 (6.1°C +
0.5)
14°F + 1 (7.7°C + 0.5)
102 Reheat
19°F + 1 (6.7°C +
0.5)
14°F + 1 (7.7°C + 0.5)
120 9°F + 1 (5.0°C + 0.5) 13°F + 1 (7.2°C + 0.5)
120 Reheat
15°F + 1 (8.3°C +
0.5)
8°F + 1 (4.4°C + 0.5)
150
10°F + 1 (5.6°C +
0.5)
11°F + 1 (6.1°C + 0.5)
150 Reheat
22°F + 1 (12°C +
0.5)
8°F + 1 (4.4°C + 0.5)