Lennox 13ACX Installation And Service Procedure page 36

FOR COMPLETE CHARGING DETAILS, REFER TO THE OUTDOOR UNIT INSTALLATION INSTRUCTION.
AIRFLOW CHECK - Both airflow and refrigerant charge must be monitored
for a proper system set‐up. It may be necessary to alternately check and
adjust the airflow and the refrigerant charge.
NOTE - Be sure that filters and indoor and outdoor coils are clean before testing.
To determine temperature drop across indoor coil (Delta-T), measure the entering air dry
bulb (DB) and wet bulb (WB) temperatures at the indoor coil. Find Delta-T in table 1. Measure
coil's leaving air DB and subtract that value from entering air DB. The measured difference
should be within +3ºF (+1.8ºC) of table value; if too low, decrease the indoor fan speed (refer
to indoor unit for information). If the Delta-T is too high, increase the indoor fan speed. Repeat
charging procedure and Delta-T (air flow adjustment) procedure until both are correct.
Example:
assume entering air DB - 72, WB - 64, leaving DB - 53. Therefore, Delta-T should
be 15 (per table); delta across coil is 72 - 53 or 19 (which is 4ºF higher than table value); action
necessary: increase fan speed.
Table 1. Evaporator Coil Delta-T
Dry bulb 80 24 24 24 23 23 22 22 22 20 19 18 17 16 15
temperature 78 23 23 23 22 22 21 21 20 19 18 17 16 15 14
of air 76 22 22 22 21 21 20 19 19 18 17 16 15 14 13
entering 74 21 21 21 20 19 19 18 17 16 16 15 14 13 12
indoor 72 20 20 19 18 17 17 16 15 15 14 13 12 11 10
coil (ºF) 70 19 19 18 18 17 17 16 15 15 14 13 12 11 10
ºF 57 58 59 60 61 62 63 64 65 66 67 68 69 70
[ Wet bulb temperature of air entering indoor coil
Table 2. Superheat (SH) Value
40 15 18 20 23 26 29 32 34 38 41 43 46 48 51
45 13 16 18 21 24 27 30 33 36 39 41 44 46 49
50 11 14 16 19 22 25 28 31 34 37 39 42 44 47
Dry bulb 55 9 12 14 17 20 23 27 30 33 36 38 40 42 44
temperature 66 7 10 12 15 18 21 24 27 30 33 35 38 40 43
of ambient 65 ‐ 6 10 13 16 19 21 24 27 30 33 36 38 41
air entering 70 ‐ ‐ 7 10 13 16 19 21 24 27 30 33 36 39
outdoor 75 ‐ ‐ ‐ 6
unit (ºF) 80 ‐ ‐ ‐ ‐
85 ‐ ‐ ‐ ‐
90 ‐ ‐ ‐ ‐
95 ‐ ‐ ‐ ‐
100 ‐ ‐ ‐ ‐
105 ‐ ‐ ‐ ‐
110 ‐ ‐ ‐ ‐
115 ‐ ‐ ‐ ‐
ºF 50 52 54 56 58 60 62 64 66 68 70 72 74 76
[ Wet bulb temperature of air entering indoor coil
07/09
*2P0709*
RFC System - +5ºF
9 12 15 18 21 24 28 31 34 37
5 8 12 15 18 21 25 28 31 35
‐ ‐ 8 11 15 19 22 26 30 33
‐ ‐ 5 9 13 16 20 24 27 31
‐ ‐ ‐ 6 10 14 18 22 25 29
‐ ‐ ‐ ‐ 8 12 16 21 24 28
‐ ‐ ‐ ‐ 5 9 13 17 22 26
‐ ‐ ‐ ‐ ‐ 6 11 15 20 25
‐ ‐ ‐ ‐ ‐ ‐ 8 14 18 24
CHARGING INFORMATION
Size
Table 3. Normal Operating Pressures
2
°F(°C) TXV System - Liquid Line (+10 psig) / Vapor Line (+5 psig)
65 (18) 233 / 132
70 (21) 251 / 133
75 (24) 265 / 133
80 (27) 292 / 135
85 (29) 314 / 136
90 (32) 338 / 137
95 (35) 362 / 138
100 (38) 388 / 140
105 (41) 415 / 141
110 (43) 444 / 142
115 (45) 475 / 143
2
°F(°C) Fixed Orifice (RFC) - Liquid Line (+10 psig) / Vapor Line (+5 psig)
65 (18) 233 / 121
70 (21) 250 / 124
]
75 (24) 270 / 128
80 (27) 291 / 131
85 (29) 313 / 134
90 (32) 335 / 136
95 (35) 359 / 138
100 (38) 383 / 140
105 (41) 409 / 142
110 (43) 436 / 145
115 (46) 464 / 147
Table 4. Approach (APP) Values
All 4 (2.2)
Table 5. Subcooling (SC) Values
All 10 (5.6)
1 Typical pressures; indoor evaporator match up, indoor air quantity, and evaporator load will cause
the pressures to vary.
2 Temperature of air entering outside coil.
3 Approach = Liquid Line Temp. minus Outdoor Ambient Temperature
4 Subcooling = Saturation Temp. minus Liquid Line Temp Temperature
]
-18 -24 -30 -36
1
244 / 137 248 / 127 263 / 135
263 / 138 263 / 131 281 / 138
285 / 139 284 / 132 302 / 140
307 / 140 307 / 134 325 / 142
329 / 141 330 / 135 349 / 142
354 / 142 355 / 136 375 / 143
379 / 143 380 / 137 404 / 144
404 / 144 407 / 138 433 / 145
438 / 145 434 / 139 462 / 147
464 / 147 465 / 141 494 / 149
495 / 148 497 / 142 527 / 150
246 / 126 245 / 123 261 / 134
265 / 129 265 / 126 281 / 136
286 / 132 286 / 129 301 / 138
307 /135 308 / 132 324 / 140
330 / 137 331 / 135 346 / 142
353 / 140 355 / 138 371 / 144
378 / 142 380 / 140 396 / 146
402 / 143 405 / 142 422 / 148
428 / 145 431 / 144 448 / 150
456 / 147 458 / 146 477 / 151
486 / 149 487 / 148 506 / 153
3
-
TXV System - ºF (ºC) +1ºF (0.5ºC)
8 (4.4) 8 (4.4) 11 (6.1)
4
-
TXV System - ºF (ºC) +1ºF (0.5ºC)
10 (5.6) 9 (5.0) 12 (6.7)
*P580052-01*
-42 -48 -60
238 / 132 235 / 132 241 / 130
262 / 133 254 / 132 260 / 130
280 / 134 276 / 134 280 / 132
301 / 136 298 / 134 299 / 134
327 / 137 323 / 135 321 / 135
353 / 138 350 / 137 344 / 134
377 / 140 377 / 138 371 / 135
404 / 141 406 / 140 400 / 137
435 / 142 430 / 141 428 / 139
465 / 143 464 / 142 458 / 141
499 / 144 495 / 143 484 / 142
246 / 126 247 / 125 248 / 124
263 / 128 266 / 128 266 / 126
284 / 131 286 / 131 288 / 130
305 / 133 307 / 133 309 / 133
327 / 135 329 / 135 330 / 135
350 / 138 353 / 138 354 / 138
374 / 140 377 / 140 377 / 140
399 / 142 403 / 142 406 / 142
424 / 144 428 / 144 431 / 144
452 / 146 455 / 146 457 / 146
481 / 148 483 / 147 484 / 148
9 (5.0) 8 (4.4) 9 (5.0)
9 (5.0) 9 (5.0) 7 (3.9)
580052-01