Lennox LHT Series Service Manual page 30

TABLE 6
156 Compressor 1 Frequency 56Hz - 581167-01
Outdoor
Circuit 1
Coil En-
tering Air
Temp⁰F
Dis. +10 Suc. +5
psig
65 218
75 262
85 305
95 350
105 400
110 454
TABLE 7
180 Compressor 1 Frequency 56Hz - 581168-01
Outdoor
Circuit 1
Coil En-
tering Air
Temp⁰F
Dis. +10 Suc. +5
psig
65 243
75 280
85 321
95 366
105 415
110 469
Circuit 2
Dis. +10 Suc. +5
psig psig psig
110 232 118
129 279 138
146 319 144
149 365 148
152 416 150
155 471 153
Circuit 2
Dis. +10 Suc. +5
psig psig psig
133 248 132
137 286 135
141 328 138
144 374 140
146 424 143
149 477 146
240 Compressor 1 Frequency 68Hz - 581169-01
Outdoor
Coil En-
tering Air
Temp⁰F
Dis. +10
psig
65 260
75 297
85 338
95 384
105 434
110 485
B-Charge Verification - Approach Method - AHRI
Testing (Fin/Tube Coil)
1 - 1- Using the same thermometer, compare liquid
temperature to outdoor ambient temperature.
Approach Temperature = Liquid temperature (at
outdoor coil outlet) minus ambient temperature.
2 - Approach temperature should match values in table
9. An approach temperature greater than value
shown indicates an undercharge. An approach
temperature less than value shown indicates an
overcharge.
3 - The approach method is not valid for grossly over or
undercharged systems. Use tables 6, 7 and 8 as a
guide for typical operating pressures.
APPROACH TEMPERATURES - FIN/TUBE COIL
Unit
156 5°F + 1 (2.8°C +0.5) 4.0°F + 1 (2.2°C +0.5)
180 2°F + 1 (1.1°C +0.5) 5.0°F + 1 (2.8°C +0.5)
240 6°F + 1 (3.3°C +0.5)
Page 30
TABLE 8
Circuit 1 Circuit 2
Suc. +5 Dis. +10
psig psig
135 264
136 304
138 346
140 394
142 443
144 494
TABLE 9
Liquid Temp. Minus Ambient Temp.
1st Stage 2nd Stage
6°F + 1 (3.3°C +0.5)
Suc. +5
psig
135
136
138
140
142
144