Lennox LCH060H4E

Page 45
If weighing facilities are not available, or to check the
charge, use the following procedure:
IMPORTANT - Charge unit in standard cooling mode
high stage only
.
1- Make sure outdoor coil is clean. Attach gauge manifolds
and operate unit at full CFM in cooling mode with econo
mizer disabled until system stabilizes (approximately five
minutes). Make sure all outdoor air dampers are closed.
2- Compare the normal operating pressures (see tables
17 - 25) to the pressures obtained from the gauges.
Check unit components if there are significant differ
ences.
3- Measure the outdoor ambient temperature and the suc
tion pressure. Refer to the appropriate circuit charging
curve to determine a target liquid temperature.
Note - Pressures are listed for sea level applications.
4- Use the same thermometer to accurately measure the
liquid temperature (in the outdoor section).
D If measured liquid temperature is higher than the
target liquid temperature, add refrigerant to the
system.
D If measured liquid temperature is lower than the
target liquid temperature, recover some refrigerant
from the system.
5- Add or remove charge in increments. Allow the system
to stabilize each time refrigerant is added or removed.
6- Continue the process until measured liquid tempera
ture agrees with the target liquid temperature. Do not
go below the target liquid temperature when adjusting
charge. Note that suction pressure can change as
charge is adjusted.
7- Example LGH/LCH036H: At 95°F outdoor ambient and
a measured suction pressure of 130psig, the target liq
uid temperature is 98°F. For a measured liquid temper
ature of 106°F, add charge in increments until mea
sured liquid temperature agrees with the target liquid
temperature.
TABLE 17
LGH/LCH036S/H NORMAL OPERATING PRESSURES - ALL-ALUMINUM COIL
Outdoor Coil Entering Air Temperature
65 °F 75 °F 85 °F 95 °F 105 °F 115 °F
Suct
(psig)
Disc
(psig)
Suct
(psig)
Disc
(psig)
Suct
(psig)
Disc
(psig)
Suct
(psig)
Disc
(psig)
Suct
(psig)
Disc
(psig)
Suct
(psig)
Disc
(psig)
114 239 117 279 118 329 119 381 122 441 124 516
121 242 123 284 126 328 128 379 129 442 132 517
138 252 142 291 145 335 148 382 151 434 152 506
156 266 160 301 164 344 168 393 172 446 175 503
TABLE 18
LGH/LCH036S/H REHEAT NORMAL OPERATING PRESSURES - ALL-ALUMINUM COIL
Outdoor Coil Entering Air Temperature
65 °F 75 °F 85 °F 95 °F 105 °F 115 °F
Suct
(psig)
Disc
(psig)
Suct
(psig)
Disc
(psig)
Suct
(psig)
Disc
(psig)
Suct
(psig)
Disc
(psig)
Suct
(psig)
Disc
(psig)
Suct
(psig)
Disc
(psig)
113 236 116 273 117 316 119 362 119 415 121 480
121 240 124 276 126 318 129 363 130 414 132 475
138 251 142 288 144 330 147 375 150 425 153 482
153 268 159 301 164 342 168 388 171 439 175 496
TABLE 19
LGH/LCH048S/H NORMAL OPERATING PRESSURES - ALL-ALUMINUM COIL
Outdoor Coil Entering Air Temperature
65 °F 75 °F 85 °F 95 °F 105 °F 115 °F
Suct
(psig)
Disc
(psig)
Suct
(psig)
Disc
(psig)
Suct
(psig)
Disc
(psig)
Suct
(psig)
Disc
(psig)
Suct
(psig)
Disc
(psig)
Suct
(psig)
Disc
(psig)
114 244 117 282 116 329 116 383 118 457 119 551
123 249 125 288 125 332 125 382 127 446 134 486
139 259 142 298 146 341 148 388 148 447 155 499
155 274 161 313 164 357 168 404 171 457 176 511