Subcooling Charging In Cooling Above 55°F Od Ambient; Subcooling Charging Below 55°F Od Ambient - In Heating Only - Trane 2TWR3 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 13 SEER 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 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 pres-
sure to match the table, or remove refrigerant to lower
the pressure. Again, wait 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.
SUBCOOL CHARGING TABLE CORRECTIONS FOR LINE LENGTH AND RISE
60
50
40
30
25
20
15
10
0 Subtract 5 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
Use Design Subcool Value from Table
10 20 25
TOTAL REFRIGERANT LINE LENGTH (FEET)
R-22 SUBCOOLING CHARGING TABLE
DESIGN SUBCOOLING VALUES (°F)
LIQUID
TEMP. 8
(°F)
LIQUID LINE PRESSURE (psi)
45 89
50 98
55 107
60 117
65 128
70 139
75 151
80 163
85 176
90 190
95 205
100 220
105 236
110 253
115 271
120 289
125 309
Add 5 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.
10 12 14
93 96 100
102 105 109
111 115 119
121 126 130
132 137 141
144 148 153
156 161 166
168 174 179
182 187 193
196 202 208
211 217 223
226 233 239
243 249 256
260 267 274
278 285 293
297 305 313
317 325 333
60 80
18-BC59D1-1