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F-Refrigerant Charge and Check - Fin/Tube Coil & RFC
LGH/LCH092H, 102H, 120H, 150S
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
60F (15C). In temperatures below 60F (15C), 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 standard cooling mode.
1- Make sure outdoor coil is clean. Attach gauge
manifolds and operate unit at full CFM 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. Compare the normal operating pressures
(see table 18) to the pressures obtained from the
gauges. Check unit components if there are
significant differences.
3- Measure the outdoor ambient temperature and the
suction pressure. Refer to the appropriate circuit
charging curve to determine a target liquid
temperature.
Note - Pressures are listed for sea level applications.
4- Use the same thermometer to accurately measure the
liquid temperature (in the outdoor section).
If measured liquid temperature is higher than
the target liquid temperature, add refrigerant to
the system.
If measured liquid temperature is lower than
the target liquid temperature, recover some
refrigerant from the system.
5- Add or remove charge in increments. Allow the
system to stabilize each time refrigerant is added or
removed.
6- Continue the process until measured liquid
temperature agrees with the target liquid
temperature. Do not go below the target liquid
temperature when adjusting charge. Note that
suction pressure can change as charge is adjusted.
7- Example LGH/LCH150 Circuit 1: At 95°F outdoor
ambient and a measured suction pressure of
130psig, the target liquid temperature is 96°F. For a
measured liquid temperature of 106°F, add charge in
increments until measured liquid temperature agrees
with the target liquid temperature.
TABLE 18
LGH/LCH150S Normal Operating Pressures - Fin/Tube - RFC
Outdoor Coil Entering Air Temperature
65 F 75 F 85 F 95 F 105 F 115 F
Suct
(psig)
Disc
(psig)
Suct
(psig)
Disc
(psig)
Suct
(psig)
Disc
(psig)
Suct
(psig)
Disc
(psig)
Suct
(psig)
Disc
(psig)
Suct
(psig)
Disc
(psig)
Circuit 1
108 253 112 295 114 338 117 384 119 438 122 501
114 255 119 296 122 342 125 390 127 444 129 501
119 257 129 303 136 348 141 403 145 460 149 522
125 264 136 308 146 358 155 413 161 470 167 530
Circuit 2
108 273 111 314 114 356 117 400 119 451 121 508
115 277 119 318 122 362 125 409 128 460 129 512
124 284 131 327 137 372 141 422 145 474 147 532
131 289 140 334 148 382 155 434 160 486 163 541
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