Lennox HSXA15 SERIES, Installation Instructions Manual, Page: 16 / 18

Page 16
listed indicate that the system is undercharged. Verify
pressures with the R410A refrigerant pressure chart in
table 6. Verify adjusted charge using the approach
method.
Approach Method
4 − Use the same digital thermometer you used to check
the outdoor ambient temperature to check the liquid
line temperature.
5 − The difference between the ambient and liquid temper-
atures should match values given in table 4. If the val-
ues don’t agree with the those in table 4, add refriger-
ant to lower the approach temperature, or recover re-
frigerant from the system to increase the approach
temperature.
Table 4
Model Number
Approach Temperature
Liquid Line Temp. − Outdoor Ambient °F (°C)
HSXA15−024 8 ± 1 (4.5 ± .5)
HSXA15−030 8 ± 1 (4.5 ± .5)
HSXA15−036 6 ± 1 (3.3 ± .5)
HSXA15−042 9 ± 1 (5 ± .5)
HSXA15−048 8 ± 1 (4.5 ± .5)
HSXA15−060 12 ± 1 (6.7 ± .5)
NOTE − For best results, the same electronic thermometer
should be used to check both outdoor ambient and liquid line
temperatures.
Table 5
Normal Operating Pressure
s
(Liquid ±10 and Vapor ±5 psig)
Mode
Outdoor Coil
Entering Air
HSXA15−024 HSXA15−030 HSXA15−036 HSXA15−042 HSXA15−048 HSXA15−060
Mode
Entering Air
Temp. °F (°C)
Liquid
Vapor
Liquid
Vapor
Liquid
Vapor
Liquid
Vapor
Liquid
Vapor
Liquid
Vapor
65
(18.3)
239 129 232 130 235 128 241 131 226 130 240 130
75
(23.9)
278 131 271 132 276 130 282 133 266 132 279 132
TXV
85
(29.4)
321 133 314 135 320 132 326 135 310 135 321 135
95
(35.0)
368 135 360 137 367 134 373 137 356 137 368 137
105
(40.6)
420 138 412 140 421 137 424 139 407 139 418 140