Lennox LGH094U Unit Information page 52

TABLE 15
LGH/LCH150S Fin/Tube Coil - TXV
CIRCUIT 1
Outdoor
Dis­
Coil
charge Suction
Entering
+5 psig
+10 psig
Air Temp
655 F 275
755 F 312
855 F 354
955 F 398
1055 F 449
1155 F 500
TABLE 16
LGH/LCH150S Fin/Tube Coil Hot Gas Reheat - TXV
CIRCUIT 1
Outdoor
Dis­
Coil
Suction
charge
Entering
+10 psig +5 psig
Air Temp
655 F 280
755 F 319
855 F 360
955 F 407
1055 F 455
1155 F 510
TABLE 17
LGH/LCH150H Fin/Tube - TXV
CIRCUIT 1
Outdoor
Dis­
Coil
Suction
charge
Entering
+10 psig +5 psig
Air Temp
65°F 276
75°F 317
85°F 357
95°F 399
105°F 450
115°F 502
TABLE 18
LGH/LCH150H Fin/Tube Hot Gas Reheat - TXV
CIRCUIT 1
Outdoor
Dis­
Coil
Suction
charge
Entering
+5 psig
+10 psig
Air Temp
65° F 296
75° F 334
85° F 378
95° F 422
105° F 470
115° F 520
Charge Verification - Approach Method - AHRI Testing
(Fin/Tube Coil Continued)
1- Using the same thermometer, compare liquid tempera­
ture to outdoor ambient temperature.
Approach Temperature = Liquid temperature (at con­
denser outlet) minus ambient temperature.
2- Approach temperature should match values in table 19.
An approach temperature greater than value shown indi­
cates an undercharge. An approach temperature less
than value shown indicates an overcharge.
CIRCUIT 2
Dis­
charge Suction
+5 psig
+10 psig
140 298 139
142 335 141
143 374 142
146 419 146
149 465 148
151 514 150
CIRCUIT 2
Dis­
Suction
charge
+10 psig +5 psig
136 296 136
141 335 141
142 376 143
144 420 144
147 466 147
150 518 150
CIRCUIT 2
Dis­
Suction
charge
+10 psig +5 psig
131 275 125
133 314 128
136 363 131
139 408 136
142 457 140
145 509 142
CIRCUIT 2
Dis­
Suction
charge
+5 psig
+10 psig
135 286 135
137 318 136
139 364 138
142 409 140
144 458 142
147 509 146
3- The approach method is not valid for grossly over or
undercharged systems. Use tables 9 through 18 as a
guide for typical operating pressures.
APPROACH TEMPERATURE - FIN/TUBE COIL - TXV
Unit
092 6°F + 1 (3.3°C + 0.5)
102 6°F + 1 (3.3°C + 0.5)
120 & 150S 6°F + 1 (3.3°C + 0.5)
150H 4°F + 1 (2.2°C + 0.5)
092, 120 & 150
6°F + 1 (3.3°C + 0.5)
Hot Gas Reheat
102
6°F + 1 (3.3°C + 0.5)
Hot Gas Reheat
F-Refrigerant Charge and Check - Fin/Tube Coil & RFC
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, re­
claim 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 standard cooling mode.
1- Make sure outdoor coil is clean. Attach gauge manifolds
and operate unit at full CFM in cooling mode with econo­
mizer disabled until system stabilizes (approximately five
minutes). Make sure all outdoor air dampers are closed.
2- Check each system separately with all stages operat­
ing. Compare the normal operating pressures (see table
20) to the pressures obtained from the gauges. Check
unit components if there are significant differences.
3- Measure the outdoor ambient temperature and the suc­
tion 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).
D If measured liquid temperature is higher than the
target liquid temperature, add refrigerant to the
system.
D 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 tempera­
ture agrees with the target liquid temperature. Do not
go below the target liquid temperature when adjusting
Page 52
TABLE 19
Liquid Temp. Minus Ambient Temp.
1st Stage 2nd Stage
7°F + 1 (3.9°C + 0.5)
9°F + 1 (5.0°C + 0.5)
10°F+1 (5.6°C + 0.5)
6°F+1 (3.3°C + 0.5)
8°F + 1
(4.4°C + 0.5)
9°F + 1
(5.0°C + 0.5)
LGH/LCH150S