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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
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
LGH/LCH092H All-Aluminum Coil Normal Operating Pressures - TXV
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)
Circuit
1
110 235 113 273 116 316 117 363 120 423 123 478
120 235 122 275 124 319 124 367 129 419 131 480
140 241 141 278 142 321 145 370 148 420 150 479
158 248 162 285 166 328 168 374 170 427 173 481
Circuit
2
111 233 114 270 117 310 116 362 119 417 122 481
120 236 122 272 124 314 126 359 128 415 130 482
140 239 142 275 143 317 147 359 148 412 151 472
158 247 163 282 167 323 169 368 171 417 173 473
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