Weigh In Charge; Subcooling Charge - Lennox XP14 SERIES Unit Information

Pre−Charge Maintenance Checks
Use table 5 as a general guide when performing maintenance checks. This is not a procedure for charging the
unit (Refer to Charging / Checking Charge section). Minor variations in these pressures may be expected due to
differences in installations. Significant differences could mean that the system is not properly charged or that
a problem exists with some component in the system.
Normal Operating Pressures − Liquid +10 and Vapor +5 PSIG* (Cooling)
XP14−018
Liquid /
Vapor
5F (5C)**
60 (15) 346 / 139
50 (10) 323 / 117
40 (4) 306 / 98
30 (−1) 278 / 84
20 (−7) 273 / 66
65 (18) 226 / 140
70 (21) 244 / 141
75 (24) 263 / 142
80 (27) 283 / 143
85 (29) 302 / 144
90 (32) 328 / 145
95 (35) 351 / 146
100 (38) 376 / 147
105 (41) 402 / 148
110 (38) 430 / 149
115 (45) 465 / 150
*IMPORTANT These are most popular match−up pressures. Indoor match up, indoor air quality, and indoor
load cause pressures to vary.
**Temperature of the air entering the outside coil.

Weigh in Charge

1. Recover the refrigerant from the unit.
2. Conduct leak check; evacuate as previously outlined.
3. Weigh in the unit nameplate charge plus any charge re-
quired for line set differences from 15 feet and any extra
indoor unit match−up amount per table 7. (If weighing
facilities are not available, use the subcooling method.)
TABLE 6
Charge per Line Set Lengths
Liquid Line Oz. per 5 ft. (g per 1.5m) adjust from
Set Diameter 15 ft. (4.6m) line set*
3/8 in. (9.5mm) 3 ounce per 5 ft. (85g per 1.5m)
NOTE − *If line length is greater than 15 ft. (4.6 m), add this amount. If
line length is less than 15 ft. (4.6 m), subtract this amount.
IMPORTANT
XP14−024 XP14−030
Liquid / Liquid /
Vapor Vapor
352 / 138 338 / 137
331 / 114 334 / 112
304 / 99 312 / 93
299 / 80 302 / 74
283 / 66 280 / 53
233 / 137 238 / 138
252 / 138 263 / 139
271 / 140 279 / 139
292 / 141 299 / 140
314 / 142 324 / 141
338 / 143 340 / 142
361 / 145 375 / 145
387 / 146 397 / 145
412 / 147 424 / 147
441 / 148 454 / 150
471 / 151 485 / 150
TABLE 5
XP14−036 XP14−042
Liquid/ Liquid /
Vapor Vapor
Heating
350 / 134 373 / 139
331 / 117 363 / 117
313 / 97 348 / 97
298 / 83 336 / 74
284 / 66 322 / 64
Cooling
220 / 138 223 / 125
236 / 140 241 / 130
256 / 141 261 / 134
276 / 142 282 / 138
298 / 143 302 / 139
321 / 144 326 / 140
344 / 144 349 / 141
369 / 146 374 / 142
394 / 147 399 / 143
421 / 148 428 / 145
449 / 149 455 / 146

Subcooling Charge

Requirements these items are required for charging:
Manifold gauge set connected to unit.
Thermometers for measuring outdoor ambient, liquid line,
and vapor line temperatures.
When to use cooling mode When outdoor temperature
is 60°F (15°C) and above, use cooling mode to adjust
charge.
When to use heating mode When the outdoor tempera-
ture is below 60°F (15°C), use the heating mode to adjust
the charge.
Adding Charge for Indoor Match−Up Table 7 lists all the
Lennox recommended indoor unit matches along with the
charge levels for the various sizes of outdoor units.
Page 18
XP14−048 XP14−060
Liquid / Liquid /
Vapor Vapor
355 / 130 351 / 117
336 / 113 333 / 105
315 / 88 316 / 88
296 / 72 308 / 70
286 / 64 300 / 61
231 / 136 243 / 136
248 / 139 263 / 137
271 / 140 282 / 138
291 / 142 306 / 139
312 / 143 327 / 140
335 / 144 351 / 141
359 / 145 376 / 142
384 / 146 401 / 143
411 / 148 426 / 145
439 / 149 452 / 146
468 / 150 484 / 148