Lennox LCH092H Unit Information page 51

mizer disabled until system stabilizes (approximately five
minutes). Make sure all outdoor air dampers are closed.
2 Check each system separately with all stages operat­
ing. Compare the normal operating pressures (see ta­
bles 4 - 7) 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.
65 °F
Suct Disc
(psig) (psig)
110 234
118 236
Circuit 1
136 240
157 248
112 232
119 237
Circuit 2
134 243
155 253
LGH/LCH092H Normal Operating Pressures - All-Aluminum - TXV
Outdoor Coil Entering Air Temperature
75 °F
Suct Disc Suct
(psig) (psig) (psig)
112 273 115
120 275 123
139 278 142
159 284 163
115 269 117
122 273 125
139 279 143
156 287 161
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 LCH092 Circuit 1: At 95°F outdoor ambient
and a measured suction pressure of 130psig, the target
liquid temperature is 96°F. For a measured liquid tem­
perature of 106°F, add charge in increments until mea­
sured liquid temperature agrees with the target liquid
temperature.
TABLE 4
85 °F 95 °F
Disc Suct Disc
(psig) (psig) (psig)
317 116 367
319 125 369
320 145 369
325 166 373
313 118 371
316 128 367
320 146 370
328 165 376
Page 51
105 °F 115 °F
Suct Disc Suct
(psig) (psig) (psig)
119 428 121
127 426 130
147 422 150
168 424 171
120 441 122
129 431 132
149 424 151
169 427 172
Disc
(psig)
503
497
483
482
523
508
488
487