Lennox Elite XP14018, Unit Information

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Page 18
Pre−Charge Maintenance Checks
IMPORTANT
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.
TABLE 5
Normal Operating Pressures − 10 and Vapor +5 PSIG* (Cooling)
XP14−018 XP14−024 XP14−030 XP14−036 XP14−042 XP14−048 XP14−060
5
F (
5
C)**
Liquid /
Vapor
Liquid /
Vapor
Liquid /
Vapor
Liquid/
Vapor
Liquid /
Vapor
Liquid /
Vapor
Liquid /
Vapor
Heating
60 (15) 346 / 139 352 / 138 338 / 137 350 / 134 373 / 139 355 / 130 351 / 117
50 (10) 323 / 117 331 / 114 334 / 112 331 / 117 363 / 117 336 / 113 333 / 105
40 (4) 306 / 98 304 / 99 312 / 93 313 / 97 348 / 97 315 / 88 316 / 88
30 (−1) 278 / 84 299 / 80 302 / 74 298 / 83 336 / 74 296 / 72 308 / 70
20 (−7) 273 / 66 283 / 66 280 / 53 284 / 66 322 / 64 286 / 64 300 / 61
Cooling
65 (18) 226 / 140 233 / 137 238 / 138 220 / 138 223 / 125 231 / 136 243 / 136
70 (21) 244 / 141 252 / 138 263 / 139 236 / 140 241 / 130 248 / 139 263 / 137
75 (24) 263 / 142 271 / 140 279 / 139 256 / 141 261 / 134 271 / 140 282 / 138
80 (27) 283 / 143 292 / 141 299 / 140 276 / 142 282 / 138 291 / 142 306 / 139
85 (29) 302 / 144 314 / 142 324 / 141 298 / 143 302 / 139 312 / 143 327 / 140
90 (32) 328 / 145 338 / 143 340 / 142 321 / 144 326 / 140 335 / 144 351 / 141
95 (35) 351 / 146 361 / 145 375 / 145 344 / 144 349 / 141 359 / 145 376 / 142
100 (38) 376 / 147 387 / 146 397 / 145 369 / 146 374 / 142 384 / 146 401 / 143
105 (41) 402 / 148 412 / 147 424 / 147 394 / 147 399 / 143 411 / 148 426 / 145
110 (38) 430 / 149 441 / 148 454 / 150 421 / 148 428 / 145 439 / 149 452 / 146
115 (45) 465 / 150 471 / 151 485 / 150 449 / 149 455 / 146 468 / 150 484 / 148
*IMPORTANTThese 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
Set Diameter Oz. per 5 ft. (g per 1.5m) adjust from
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.
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.