13ACX CHARGING INFORMATION
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 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
(RFC)
Suction line saturation temperature minus suction line temperature.
Outdoor
Temp (ºF)
65
70
75
80
85
90
95
100
105
Superheat
(ºF)
35
30
25
22
18
12
8
5
5
All measurements are at the service valves and are based on 80db / 67wb indoor temperature.
Table 3. RFC Sizes
Unit Size
-18
-24
-30
-36
-42
-48
-60
RFC Size
0.053
0.057
0.063
0.072
0.074
0.082
0.090
Table 4. Normal Operating Pressures
1
Size
-18
-24
-30
-36
-42
-48
-60
°F(°C)
2
Fixed Orifice (RFC)
- Liquid Line (+10 psig) / Vapor Line (+5 psig)
65 (18)
233 / 121
246 / 126
245 / 123
261 / 134
246 / 126
247 / 125
248 / 124
70 (21)
250 / 124
265 / 129
265 / 126
281 / 136
263 / 128
266 / 128
266 / 126
75 (24)
270 / 128
286 / 132
286 / 129
301 / 138
284 / 131
286 / 131
288 / 130
80 (27)
291 / 131
307 /135
308 / 132
324 / 140
305 / 133
307 / 133
309 / 133
85 (29)
313 / 134
330 / 137
331 / 135
346 / 142
327 / 135
329 / 135
330 / 135
90 (32)
335 / 136
353 / 140
355 / 138
371 / 144
350 / 138
353 / 138
354 / 138
95 (35)
359 / 138
378 / 142
380 / 140
396 / 146
374 / 140
377 / 140
377 / 140
100 (38)
383 / 140
402 / 143
405 / 142
422 / 148
399 / 142
403 / 142
406 / 142
105 (41)
409 / 142
428 / 145
431 / 144
448 / 150
424 / 144
428 / 144
431 / 144
110 (43)
436 / 145
456 / 147
458 / 146
477 / 151
452 / 146
455 / 146
457 / 146
115 (46)
464 / 147
486 / 149
487 / 148
506 / 153
481 / 148
483 / 147
484 / 148
°F(°C)
2
TXV System
- Liquid Line (+10 psig) / Vapor Line (+5 psig)
65 (18)
233 / 132
244 / 137
248 / 127
263 / 135
238 / 132
235 / 132
241 / 130
70 (21)
251 / 133
263 / 138
263 / 131
281 / 138
262 / 133
254 / 132
260 / 130
75 (24)
265 / 133
285 / 139
284 / 132
302 / 140
280 / 134
276 / 134
280 / 132
80 (27)
292 / 135
307 / 140
307 / 134
325 / 142
301 / 136
298 / 134
299 / 134
85 (29)
314 / 136
329 / 141
330 / 135
349 / 142
327 / 137
323 / 135
321 / 135
90 (32)
338 / 137
354 / 142
355 / 136
375 / 143
353 / 138
350 / 137
344 / 134
95 (35)
362 / 138
379 / 143
380 / 137
404 / 144
377 / 140
377 / 138
371 / 135
100 (38)
388 / 140
404 / 144
407 / 138
433 / 145
404 / 141
406 / 140
400 / 137
105 (41)
415 / 141
438 / 145
434 / 139
462 / 147
435 / 142
430 / 141
428 / 139
110 (43)
444 / 142
464 / 147
465 / 141
494 / 149
465 / 143
464 / 142
458 / 141
115 (45)
475 / 143
495 / 148
497 / 142
527 / 150
499 / 144
495 / 143
484 / 142
Table 5. Approach (APP) Values
3
-
TXV System - ºF (ºC) +1ºF (0.5ºC)
All
8 (4.4)
11 (6.1)
10 (5.5)
13 (7.2)
7 (3.9)
7 (3.9)
13 (7.2)
Table 6. Subcooling (SC) Values
4
-
TXV System - ºF (ºC) +1ºF (0.5ºC)
65
5 (2.8)
8 (4.4)
5 (2.8)
3 (1.7)
8 (4.4)
6 (3.3)
4 (2.2)
75
5 (2.8)
8 (4.4)
6 (3.3)
3 (1.7)
9 (5.0)
7 (3.9)
4 (2.2)
85
5 (2.8)
8 (4.4)
6 (3.3)
4 (2.2)
9 (5.0)
7 (3.9)
5 (2.8)
95
6 (3.3)
9 (5.0)
7 (3.9)
4 (2.2)
10 (5.5)
8 (4.4)
5 (2.8)
105
7 (3.9)
9 (5.0)
8 (4.4)
5 (2.8)
11 (6.1)
9 (5.0)
5 (2.8)
115
9 (5.0)
10 (5.5)
8 (4.4)
5 (2.8)
11 (6.1)
9 (5.0)
4 (2.2)
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
*2P52013*
*P580450-01*
5/2013
580450-01
