Subcooling Charging In Cooling Above 55°F Od Ambient; Subcooling Charging Below 55°F Od Ambient - In Heating Only - Trane 4TWR3 Installer's Manual

Installer's Guide
SUBCOOLING CHARGING IN COOLING ABOVE 55°F OD AMBIENT
The Trane company has always recommended installing
Trane approved matched indoor and outdoor systems.
All Trane split systems are ARI rated with only TXV indoor
systems.
The benefits of installing approved indoor and outdoor split
systems are maximum efficiency, optimum performance and
the best overall system reliability.
The following charging methods are therefore
prescribed for systems with indoor TXVs.
1. Subcooling (in the cooling mode) is the only
recommended method of charging above
55°F ambient temperatures.
2. For best results - the indoor temperature
should be kept between 70°F to 80°F. Add
system heat if needed.
3. At start-up, or whenever charge is removed
or added, the system must be operated for a
minimum twenty (20) minutes to stabilize
before accurate measurements can be made.
4. Measure Liquid Line Temperature and
Refrigerant Pressure at service valves.
5. Determine total refrigerant line length,
and height (lift) if indoor section is above
the condenser.
6. Determine the Design Subcool Charging
Temperature from the unit nameplate.
7. Locate this value in the appropriate column
of the Subcooling Charging Table. Locate
your liquid line temperature in the left
column of the table, and the intersecting
liquid line pressure under your nameplate
subcool value column. Add refrigerant to
raise the pressure to match the table, or
SUBCOOL CHARGING TABLE CORRECTIONS FOR LINE LENGTH AND RISE
60
50
40
30
25
20
15
10
0
Subtract 10 psig from S.C. Table Pressure
SUBCOOLING CHARGING BELOW 55°F OD AMBIENT – IN HEATING ONLY
1. The Subcool Charging Method in cooling is not recom-
mended below 55°F outdoor ambient.
2. The only recommended method of charging at outdoor
ambients below 55°F, is to weigh in the charge in the
heating mode.
3. Use Nameplate charge plus standard charge adders for
line length.
6
LIQUID
TEMP
( F)
˚
55
60
65
70
75
80
85
90
95
100
105
110
115
120
125
Installer's Guide for charging method.
Use Design Subcool Value from Table
10 20 25
TOTAL REFRIGERANT LINE LENGTH (FEET)
remove refrigerant to lower the pressure. Again, wait
twenty (20) minutes for the system conditions to stabilize
before adjusting charge again.
8. When system is correctly charged, you can refer to
System Pressure Curves (in Service Facts) to verify
typical performance.
R-410A REFRIGERANT CHARGING CHART
DESIGN SUBCOOLING (
8 9 10
LIQUID GAGE PRESSURE (PSI)
179 182 185
195 198 201
211 215 218
229 232 236
247 251 255
267 271 275
287 291 296
309 313 318
331 336 341
355 360 365
381 386 391
407 413 418
435 441 446
464 470 476
495 501 507
Refer to Service Facts or
Add 10 psig to Subcool Charging Table Pressure
30 40
4. Check liquid line temperature and pressure (at the
OD valves) to obtain a minimum of 10°F subcooling.
5. Add charge if a minimum of 10°F subcooling is not obtained
with the nameplate charge plus line length correction.
6. It is important to return in the spring or summer to
accurately charge the system in the cooling mode at
outdoor ambients above 55°F.
˚ F)
11 12 13
188 191 195 198
204 208 211 215
222 225 229 232
240 243 247 251
259 263 267 271
279 283 287 291
300 304 309 313
322 327 331 336
346 351 355 360
370 376 381 386
396 402 407 413
424 429 435 441
452 458 464 470
482 488 495 501
514 520 527 533
From Dwg. D154557P01 Rev. 2
60 80
18-BC51D1-4
14