Lennox KCA092, Installation Instructions Manual

Page: 19 / 32

Page 19
2- Check each system separately with all stages
operating. Compare the normal operating pressures
(see tables 4 - 10) 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 KG/KC 092S Circuit 1: At 95°F outdoor
ambient and a measured suction pressure of
130psig, the target liquid temperature is 103°F. For a
measured liquid temperature of 112°F, add charge in
increments until measured liquid temperature agrees
with the target liquid temperature.
TABLE 4
092S Normal Operating Pressures
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
103 243 107 282 110 325 113 371 116 423 119 473
110 249 113 286 117 327 120 369 123 422 126 472
122 259 127 297 131 339 135 386 139 436 142 493
135 272 140 310 145 351 150 396 155 447 159 501
Circuit 2
106 243 111 282 113 323 117 368 119 417 123 466
113 249 117 285 120 325 123 365 126 415 130 468
127 268 131 304 135 342 139 385 143 434 147 493
141 287 146 324 150 363 154 405 159 451 163 502
092S Charging Curves
60
70
80
90
100
110
120
130
100 110 120 130 140 150 160
Liquid Temperature (
°
F)
Suction Pressure (psig)
Outdoor Temperature (°F)
115°
105°
95°
85°
75°
65°
Circuit 1
Circuit 2