Placement And Installation; Charging; Refrigerant Charge And Check; All-Aluminum Coil Normal Operating Pressures - Txv - Lennox LGH Series Unit Information

II-PLACEMENT AND INSTALLATION
Make sure the unit is installed in accordance with the in­
stallation instructions and all applicable codes. See ac­
cessories section for conditions requiring use of the op­
tional roof mounting frame (C1CURB10).
III-CHARGING
WARNING
Refrigerant can be harmful if it is inhaled. Refrigerant
must be used and recovered responsibly.
Failure to follow this warning may result in person­
al injury or death.
IMPORTANT
Units equipped with a Hot Gas Reheat system MUST be
charged in standard cooling mode.
A-Refrigerant Charge and Check - All-Aluminum Coil
092H, 102H, 120H, 150S Units
WARNING-Do not exceed nameplate charge under any
condition.
This unit is factory charged and should require no further
adjustment. If the system requires additional refrigerant, re­
claim the charge, evacuate the system, and add required
nameplate charge.
NOTE - System charging is not recommended below 60_F
(15_C). In temperatures below 60_F (15_C), the charge
must be weighed into the system.
If weighing facilities are not available, or to check the
charge, use the following procedure:
IMPORTANT - Charge unit in standard cooling mode.
1- Make sure outdoor coil is clean. Attach gauge manifolds
and operate unit at full CFM in cooling mode with econo­
LGH/LCH092H All-Aluminum Coil Normal Operating Pressures - TXV
65 °F
Suct Disc
(psig) (psig)
110 235
120 235
Circuit
1
140 241
158 248
111 233
120 236
Circuit
2 140 239
158 247
Outdoor Coil Entering Air Temperature
75 °F 85 °F
Suct Disc Suct
(psig) (psig) (psig)
113 273 116
122 275 124
141 278 142
162 285 166
114 270 117
122 272 124
142 275 143
163 282 167
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 5 - 8) 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/LCH092 Circuit 1: At 95°F outdoor am­
bient and a measured suction pressure of 130psig, the
target liquid temperature is 96°F. For a measured liquid
temperature of 106°F, add charge in increments until
measured liquid temperature agrees with the target liq­
uid temperature.
TABLE 5
95 °F
Disc Suct Disc
(psig) (psig) (psig)
316 117 363
319 124 367
321 145 370
328 168 374
310 116 362
314 126 359
317 147 359
323 169 368
Page 47
105 °F 115 °F
Suct Disc Suct
(psig) (psig) (psig)
120 423 123
129 419 131
148 420 150
170 427 173
119 417 122
128 415 130
148 412 151
171 417 173
Disc
(psig)
478
480
479
481
481
482
472
473