6
18-BC51D1-4
Installer’s Guide
SUBCOOLING CHARGING IN COOLING ABOVE 55°F OD AMBIENT
SUBCOOLING CHARGING BELOW 55°F OD AMBIENT – IN HEATING ONLY
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
Add 10 psig to Subcool Charging Table Pressure
20
15
Use Design Subcool Value from Table
10
0
Subtract 10 psig from S.C. Table Pressure
10
20
25
30
40
60
80
TOTAL REFRIGERANT LINE LENGTH (FEET)
REFRIGERANT
LINE LIFT (FEET)
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.
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.
8
9
10
11
12
13
14
55
179
182
185
188
191
195
198
60
195
198
201
204
208
211
215
65
211
215
218
222
225
229
232
70
229
232
236
240
243
247
251
75
247
251
255
259
263
267
271
80
267
271
275
279
283
287
291
85
287
291
296
300
304
309
313
90
309
313
318
322
327
331
336
95
331
336
341
346
351
355
360
100
355
360
365
370
376
381
386
105
381
386
391
396
402
407
413
110
407
413
418
424
429
435
441
115
435
441
446
452
458
464
470
120
464
470
476
482
488
495
501
125
495
501
507
514
520
527
533
R-410A REFRIGERANT CHARGING CHART
Refer to Service Facts or
Installer's Guide for charging method.
LIQUID
TEMP
(
˚
F)
DESIGN SUBCOOLING (
˚
F)
LIQUID GAGE PRESSURE (PSI)
From Dwg. D154557P01 Rev. 2
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.
