Lennox LCH036 Installation Instructions Manual page 35

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:
1- Attach gauge manifolds and operate unit in cooling
mode on HIGH SPEED with economizer disabled
until system stabilizes (approximately five minutes).
Make sure outdoor air dampers are closed.
2- Use a thermometer to accurately measure the
outdoor ambient temperature.
3- Apply the outdoor temperature to tables 14 through
27 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.
S Add or remove charge in increments.
S 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 14
LG/LC 036S NORMAL OPERATING PRESSURES
Outdoor Coil
Entering Air Temp
655 F
755 F
855 F
955 F
1055 F
1155 F
LGH/LCH036, 048, 060, 072
Discharge Suction + 5
+10 psig psig
267 138
305 140
350 142
398 146
451 147
507 150
LG/LC 036S REHEAT NORMAL OPERATING
Outdoor Coil
Entering Air Temp
655 F
755 F
855 F
955 F
1055 F
1155 F
LG/LC 036H NORMAL OPERATING PRESSURES
Outdoor Coil
Entering Air Temp
655 F
755 F
855 F
955 F
1055 F
1155 F
LG/LC 036H REHEAT NORMAL OPERATING
Outdoor Coil
Entering Air Temp
655 F
755 F
855 F
955 F
1055 F
1155 F
LG/LC 048S NORMAL OPERATING PRESSURES
Outdoor Coil
Entering Air Temp
655 F
755 F
855 F
955 F
1055 F
1155 F
LG/LC 048S REHEAT NORMAL OPERATING
Outdoor Coil
Entering Air Temp
655 F
755 F
855 F
955 F
1055 F
1155 F
Page 35
TABLE 15
PRESSURES
Discharge Suction + 5
+10 psig
261
300
342
387
437
490
TABLE 16
Discharge Suction + 5
+10 psig
262
293
345
389
439
493
TABLE 17
PRESSURES
Discharge Suction + 5
+10 psig
262
299
342
388
437
491
TABLE 18
Discharge Suction + 5
+10 psig
259
299
343
390
442
497
TABLE 19
PRESSURES
Discharge Suction + 5
+10 psig
259
298
340
388
439
495
psig
138
141
144
148
150
153
psig
142
145
147
149
152
155
psig
139
141
144
147
150
153
psig
129
138
146
148
157
160
psig
139
143
145
148
151
154