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LGH/LCH036, 048, 060, 072
C-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.
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 14
LG/LC 036S NORMAL OPERATING PRESSURES
Outdoor Coil
Entering Air Temp
Discharge
+
10 psig
Suction + 5
psig
655 F 267 138
755 F 305 140
855 F 350 142
955 F 398 146
1055 F 451 147
1155 F 507 150
TABLE 15
LG/LC 036S REHEAT NORMAL OPERATING
PRESSURES
Outdoor Coil
Entering Air Temp
Discharge
+
10 psig
Suction + 5
psig
655 F 261 138
755 F 300 141
855 F 342 144
955 F 387 148
1055 F 437 150
1155 F 490 153
TABLE 16
LG/LC 036H NORMAL OPERATING PRESSURES
Outdoor Coil
Entering Air Temp
Discharge
+
10 psig
Suction + 5
psig
655 F 262 142
755 F 293 145
855 F 345 147
955 F 389 149
1055 F 439 152
1155 F 493 155
TABLE 17
LG/LC 036H REHEAT NORMAL OPERATING
PRESSURES
Outdoor Coil
Entering Air Temp
Discharge
+
10 psig
Suction + 5
psig
655 F 262 139
755 F 299 141
855 F 342 144
955 F 388 147
1055 F 437 150
1155 F 491 153
TABLE 18
LG/LC 048S NORMAL OPERATING PRESSURES
Outdoor Coil
Entering Air Temp
Discharge
+
10 psig
Suction + 5
psig
655 F 259 129
755 F 299 138
855 F 343 146
955 F 390 148
1055 F 442 157
1155 F 497 160
TABLE 19
LG/LC 048S REHEAT NORMAL OPERATING
PRESSURES
Outdoor Coil
Entering Air Temp
Discharge
+
10 psig
Suction + 5
psig
655 F 259 139
755 F 298 143
855 F 340 145
955 F 388 148
1055 F 439 151
1155 F 495 154
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