CHARGING INFORMATION FOR 13ACD UNIT SHIPPED WITH DRY NITROGEN CHARGE
This unit is factory shipped with a nitrogen gas holding charge to
prevent moisture infiltration. The 13ACD unit is intended as a replacement
component for an existing (previously installed) system. For best results,
indoor temperature should be between 70ºF (21ºC) and 80ºF (27ºC). Be sure
to monitor system pressures while charging. Charging should be done with
unit operating in the cooling mode.
Initial Weigh-In Charge
12. After evacuation of the outdoor unit, line set, and indoor unit is complete, close
the manifold gauge set valves. Disconnect vacuum pump from center hose of
gauge set.
13. Connect the center hose of the gauge set to a cylinder of HCFC-22 and purge
the hose. Then, place the cylinder upside down on a scale.
14. Open the high side manifold gauge valve and weigh in liquid refrigerant. Refer
to unit nameplate to determine correct weigh-in charge.
15. Close the high side manifold gauge valve when proper charge has been weighed
in.
Optimizing System Charge
NOTE — Refrigerant tank should be turned right-side-up to deliver refrigerant gas
during charge optimizing procedure.
1. Make sure the refrigerant cylinder is right-side-up so that it will deliver gas
during the charge optimizing procedure.
2. Set the thermostat for a cooling demand. Turn on power to the indoor unit and
close the outdoor unit disconnect switch to start the unit.
3. Allow unit to run for five minutes to allow pressures to stabilize.
4. Check and adjust indoor airflow using procedure provided below.
5. Use either approach, subcooling or superheat method (see table 3 and 4) to
optimize system charge. Adjust charge as necessary.
NOTE — Complete procedures for approach, subcooling and superheat methods
are located in the unit installation instruction.
6. Replace the stem and service port caps and tighten.
Adjusting Indoor Airflow
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. 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. Superheat (SH) Value RFC System - +5ºF
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 12141720232730333638404244
temperature 66 7 10121518212427303335384043
of ambient 65 ‐ 6 10 13 16 19 21 24 27 30 33 36 38 41
air entering 70 ‐ ‐ 7 1013161921242730333639
outdoor 75 ‐ ‐ ‐ 6 9 121518212428313437
unit (ºF) 80 ‐ ‐ ‐ ‐ 5 8 12 15 18 21 25 28 31 35
85 ‐‐‐‐‐‐811151922263033
90 ‐‐‐‐‐‐59131620242731
95 ‐‐‐‐‐‐‐6101418222529
100 ‐‐‐‐‐‐‐‐81216212428
105 ‐‐‐‐‐‐‐‐5913172226
110 ‐‐‐‐‐‐‐‐‐611152025
115 ‐‐‐‐‐‐‐‐‐‐8141824
ºF 50 52 54 56 58 60 62 64 66 68 70 72 74 76
[ Wet bulb temperature of air entering indoor coil ]
Charging Temperatures and Pressures
Model -18 -24 -30 -36 -42 -48 -60
Table 2- Normal Operating Pressures
1
°F(°C)
2
TXV System - Liquid Line (+10 psig) / Vapor Line (+5 psig)
65 (18) 138 / 79 148 / 79 147 / 75 155 / 79 147 / 78 144 / 77 152 / 73
70 (21) 148 / 80 160 / 79 159 / 75 169 / 80 158 / 78 152 / 77 164 / 75
75 (24) 160 / 80 174 / 80 172 / 76 183 / 81 172 / 79 163 / 78 177 / 77
80 (27) 174 / 81 188 / 81 186 / 77 199 / 81 189 / 79 179 / 78 192 / 78
85 (29) 188 / 81 203 / 81 201 / 77 215 / 82 205 / 80 195 / 79 208 / 79
90 (32) 204 / 81 220 / 82 216 / 78 233 / 82 222 / 81 212 / 80 225 / 80
95 (35) 219 / 82 236 / 83 233 / 79 252 / 83 241 / 81 229 / 80 243 / 80
100 (38) 236 / 82 253 / 83 250 / 80 271 / 83 259 / 82 245 / 81 261 / 81
105 (41) 253 / 83 272 / 84 268 / 80 291 / 84 279 / 82 265 / 81 280 / 82
110 (43) 272 / 84 291 / 85 287 / 81 311 / 85 299 / 83 287 / 82 299 / 83
115 (45) 291 / 84 311 / 85 306 / 82 331 / 86 320 / 84 309 / 83 320 / 83
°F(°C)
2
Fixed Orifice - Liquid Line (+10 psig) / Vapor Line (+5 psig)
65 (18) 139 / 67 147 / 71 148 / 65 162 / 75 158 / 72 151 / 71 152 / 68
70 (21) 149 / 70 159 / 73 161 / 67 174 / 76 170 / 75 161 / 73 165 / 71
75 (24) 161 /74 172 / 75 175 / 70 187 / 78 182 / 76 172 / 75 178 / 73
80 (27) 175 / 77 186 / 77 190 / 73 201 / 79 195 / 78 185 / 76 193 / 76
85 (29) 189 / 79 200 / 79 205 / 75 215 / 81 209 / 80 198 / 77 208 / 78
90 (32) 203 / 81 216 / 81 221 / 77 231 / 82 224 / 81 213 / 79 224 / 80
95 (35) 218 / 82 232 / 82 237 / 79 247 / 83 240 / 82 227 / 80 239 / 81
100 (38) 234 / 83 247 / 83 254 / 80 265 / 84 256 / 84 243 / 81 258 / 82
105 (41) 251 / 85 264 / 85 271 / 81 283 / 85 273 / 85 259 / 82 276 / 83
110 (43) 269 / 86 285 / 86 289 / 82 302 / 86 290 / 86 276 / 84 294 / 85
115 (45) 287 / 87 302 / 87 308 / 83 321 / 87 310 / 87 293 / 85 313 / 86
Table 3- Approach (APP) Values
3
- TXV System - ºF (ºC) +1ºF (0.5ºC)
All 6 (3.3) 6 (3.3) 8 (4.4) 12 (6.7) 5 (2.8) 6 (3.3) 7 (3.8)
Table 4- Subcooling (SC) Values
4
- TXV System - ºF (ºC) +1ºF (0.5ºC)
All 7 (3.8) 12 (6.7) 9 (5) 10 (5.6) 14 (8) 10 (5.6) 13 (7.2)
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
*2P1110* *P580366-01*
11/10 580366-01
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