Lennox LCH036 Installation Instructions Manual page 176

D-Refrigerant Charge and Check
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 cooling mode. Make sure hot
gas reheat is not energized.
1- Attach gauge manifolds and operate unit in cooling
mode at full CFM with economizer disabled until system
stabilizes (approximately five minutes). Make sure all
outdoor air dampers are closed.
2- Check each system separately with all stages operating.
3- Use a thermometer to accurately measure the outdoor
ambient temperature.
4- Apply the outdoor temperature to tables 7 through 18 to
determine normal operating pressures. Pressures are
listed for sea level applications at 80°F dry bulb and
67°F wet bulb return air.
5- 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.
6- If discharge pressure is high, remove refrigerant from
the system. If discharge pressure is low, add refrigerant
to the system.
S Add or remove charge in increments.
S Allow the system to stabilize each time
refrigerant is added or removed.
7- Use the following approach method along with the
normal operating pressures to confirm readings.
LGH/LCH420S - R410A - CAV
Circuit 1 Circuit 2
Outdoor
Coil En­
Dis. Suc. Dis.
tering Air
+10 +5 +10
Temp psig psig psig
65_F* 270 131 317
75_F 313 134 341
85_F 355 136 391
95_F 396 138 446
105_F 446 140 500
115_F 500 142 552
TABLE 7
Circuit 3 Circuit 4
Suc. Dis. Suc. Dis.
+5 +10 +5 +10
psig psig psig psig
136 291 134 291
139 331 137 331
142 375 138 370
144 418 140 412
147 464 141 452
150 513 142 507
Circuit 1
Outdoor
Coil En­
Dis.
tering Air
+10
Temp psig
65_F* 280
75_F 330
85_F 380
95_F 420
105_F 495
115_F 535
Circuit 1
Outdoor
Coil En­
DIs
tering Air
+10
Temp psig
65_F* 230
75_F 290
85_F 320
95_F 390
105_F 440
115_F 500
Circuit 1
Outdoor
Coil En­
DIs
tering Air
+10
Temp psig
65_F* 250
75_F 300
85_F 330
95_F 390
105_F 420
115_F 470
Circuit 1
Outdoor
Coil En­
DIs
tering Air
+10
Temp psig
65_F* 270
75_F 313
85_F 355
95_F 396
105_F 446
115_F 500
Circuit 1
Outdoor
Coil En­
DIs
Suc.
tering Air
+10
+5
Temp psig
psig
65_F* 282
133
75_F 336
134
85_F 389
137
95_F 429
139
105_F 502
141
143 115_F 547
Page 32
TABLE 8
LGH/LCH420S - R410A - VFD
Circuit 2 Circuit 3
Suc. Dis. Suc. Dis.
+5 +10 +5 +10
psig psig psig psig
112 310 115 310
115 360 118 350
117 410 121 400
121 470 125 450
124 530 128 510
128 590 131 570
TABLE 9
LGH/LCH420H - R410 - CAV
Circuit 2 Circuit 3
Suc Dis Suc DIs
+5 +10 +5 +10
psig psig psig psig
127 300 133 260
134 330 135 300
135 380 137 340
137 430 139 390
143 490 142 440
146 550 144 500
TABLE 10
LGH/LCH420H - R410 - VFD
Circuit 2 Circuit 3
Suc Dis Suc DIs
+5 +10 +5 +10
psig psig psig psig
121 280 124 260
124 320 126 305
126 370 127 340
130 420 131 400
131 470 132 450
134 540 134 510
TABLE 11
LGH/LCH480S - R410A - CAV
Circuit 2 Circuit 3
Suc Dis Suc DIs
+5 +10 +5 +10
psig psig psig psig
131 317 136 291
134 341 139 331
136 391 142 375
138 446 144 418
140 500 147 464
142 552 150 513
TABLE 12
LGH/LCH480S - R410A - VFD
Circuit 2 Circuit 3
Suc Dis Suc DIs
+5 +10 +5 +10
psig psig psig psig
114 317 116 315
116 361 118 353
119 414 121 403
122 470 124 451
126 529 128 511
130 595 131 576
LGH/LCH420, 480, 540, 600
Circuit 4
Suc. Dis. Suc.
+5 +10 +5
psig psig psig
137 312 141
140 350 143
142 380 141
144 435 143
146 490 147
148 550 150
Circuit 4
Suc DIs Suc
+5 +10 +5
psig psig psig
130 270 130
132 300 131
135 340 132
136 370 133
139 430 137
141 490 139
Circuit 4
Suc DIs Suc
+5 +10 +5
psig psig psig
140 270 140
142 306 142
143 350 144
146 390 147
147 460 148
149 520 150
Circuit 4
Suc DIs Suc
+5 +10 +5
psig psig psig
134 291 133
137 331 134
138 370 137
140 412 139
141 452 141
142 507 143
Circuit 4
Suc DIs Suc
+5 +10 +5
psig psig psig
138 316 139
139 351 143
142 396 145
144 441 144
147 498 147
149 558 150