Page 36
LGH/LCH156, 180, 210, 240, 300S
E-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 and operate unit in cooling
mode 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 9 through 20
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.
Add or remove charge in increments.
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.
TABLE 9
LG/LC Series 156H Std.
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
255
136
263
136
273
140
75
F
292
139
301
139
311
144
85
F
333
141
342
141
353
146
95
F
378
144
387
143
398
148
105
F
431
148
438
145
449
150
115
F
484
150
490
146
502
152
TABLE 10
LG/LC Series 156H Reheat
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
265
134
273
135
273
140
75
_
F
302
138
311
138
311
144
85
_
F
343
140
352
140
353
146
95
_
F
388
143
397
142
398
148
105
_
F
441
147
448
144
449
150
115
_
F
494
149
500
145
502
152
TABLE 11
LG/LC Series 180H Std.
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*
248
137
257
135
259
137
75
F
285
139
294
137
296
137
85
F
328
143
336
139
338
140
95
F
374
146
383
141
385
144
105
F
425
148
433
144
435
147
115
F
479
151
488
147
488
151
TABLE 12
LG/LC Series 180H Reheat
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*
258
136
267
133
259
137
75
F
295
138
304
135
296
137
85
F
338
142
346
137
338
140
95
F
384
145
393
139
385
144
105
F
435
147
443
142
435
147
115
F
488
150
498
145
488
151
TABLE 13
LG/LC Series 180U
Outdoor
Coil En
tering
Air Temp
Circuit 1
Circuit 2
Dis. +10
psig
Suc. +5
psig
Dis. +10
psig
Suc. +5
psig
65
F
246
135
256
136
75
F
282
138
293
139
85
F
324
140
336
142
95
F
368
142
387
145
105
F
407
145
421
147
115
F
461
148
475
151