Lennox LCM156U, Installation Instructions Manual

Page: 21 / 48

Page 21
508117-01 2/2021
D-Refrigerant Charge and Check - Fin/Tube Coil
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,
reclaim 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 normal cooling mode.
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:
SERVICE>TEST>COOL>COOL 4
2- Use a thermometer to accurately measure the
outdoor ambient temperature.
3- Apply the outdoor temperature to tables 5 through 14
to determine normal operating pressures. Pressures
are listed for sea level applications at 80 ° F dry bulb
and 67 ° F wet bulb return air.
4- Compare the normal operating pressures to the
pressures obtained from the gauges. Minor
variations in these pressures may be expected due to
differences in installations. Significant differences
could mean that the system is not properly charged
or that a problem exists with some component in the
system.
Correct any system problems before
proceeding.
5- If discharge pressure is high, remove refrigerant from
the system. If discharge pressure is low, add
refrigerant to the system.
Add or remove charge in increments.
Allow the system to stabilize each time
refrigerant is added or removed.
6- Use the following approach method along with the
normal operating pressures to confirm readings.
TABLE 5
156 Std. Compressor 1 Frequency 56Hz - 581014-01
Outdoor
Coil En­
tering
Air
Temp
Circuit 1 Circuit 2 Circuit 3
Dis.
+10
psig
Suc.
+5
psig
Dis.
+10
psig
Suc.
+5
psig
Dis.
+10
psig
Suc.
+5
psig
65°F 228 127 256 131 258 140
75°F 267 130 295 134 298 148
85°F 309 133 337 136 340 153
95°F 352 135 383 139 387 156
105°F 403 139 432 142 433 159
115°F 457 142 485 145 486 162
TABLE 6
156 Reheat Compressor 1 Frequency 56Hz - 581015-01
Outdoor
Coil
Entering
Air
Temp
Circuit 1 Circuit 2 Circuit 3
Disch.
+10
psig
Suct.
+5
psig
Disch.
+10
psig
Suct.
+5
psig
Disch.
+10
psig
Suct.
+5
psig
65°F 230 123 274 127 260 140
75°F 267 126 313 129 299 144
85°F 309 129 353 132 341 147
95°F 355 133 398 135 385 150
105°F 404 135 447 137 432 153
115°F 463 139 507 140 485 156
TABLE 7
180 Std. Compressor 1 Frequency 56Hz - 581016-01
Outdoor
Coil
Entering
Air
Temp
Circuit 1 Circuit 2 Circuit 3
Disch.
+10
psig
Suct.
+5
psig
Disch.
+10
psig
Suct.
+5
psig
Disch.
+10
psig
Suct.
+5
psig
65°F 232 123 276 131 279 141
75°F 267 129 313 133 315 147
85°F 311 132 360 136 362 151
95°F 357 135 406 138 408 154
105°F 403 137 456 141 455 158
115°F 456 140 511 144 510 161
TABLE 8
180 Reheat Compressor 1 Frequency 56Hz - 581017-01
Outdoor
Coil
Entering
Air
Temp
Circuit 1 Circuit 2 Circuit 3
Disch.
+10
psig
Suct.
+5
psig
Disch.
+10
psig
Suct.
+5
psig
Disch.
+10
psig
Suct.
+5
psig
65°F 233 122 291 129 267 132
75°F 270 127 330 131 307 138
85°F 313 129 373 133 348 143
95°F 360 134 430 137 398 147
105°F 411 136 472 139 441 149
115°F 469 139 531 142 495 152
TABLE 9
210 Std. Compressor 1 Frequency 48Hz - 581018-01
Outdoor
Coil En­
tering
Air
Temp
Circuit 1 Circuit 2 Circuit 3 Circuit 4
Dis
+10
psig
Suc
+5
psig
Dis.
+10
psig
Suc
+5
psig
Dis.
+10
psig
Suc
+5
psig
Dis.
+10
psig
Suc.
+5
psig
65°F 245 125 255 127 253 139 259 140
75°F 283 127 294 130 290 143 299 146
85°F 323 129 336 133 330 146 343 149
95°F 368 131 386 136 376 148 393 151
105°F 418 134 435 139 425 152 440 153
115°F 472 137 489 142 479 154 496 155