Johnson Controls 13 SEER User Manual
Page 5
347337-UIM-A-0408
Johnson Controls Unitary Products
5
SECTION V: INSTALLATIONS REQUIRING
AN ADD-ON TXV KIT
For installations requiring a TXV kit, refer to the Installation Instructions
accompanying the TXV kit.
SECTION VI: EVACUATION
It will be necessary to evacuate the system to 500 microns or less. If a
leak is suspected, leak test with dry nitrogen to locate the leak. Repair
the leak and test again.
To verify that the system has no leaks, simply close the valve to the vac-
uum pump suction to isolate the pump and hold the system under vac-
uum. Watch the micron gauge for a few minutes. If the micron gauge
indicates a steady and continuous rise, it’s an indication of a leak. If the
gauge shows a rise, then levels off after a few minutes and remains
fairly constant, it’s an indication that the system is leak free but still con-
tains moisture and may require further evacuation if the reading is
above 500 microns.
SECTION VII: SYSTEM CHARGE
The factory charge in the outdoor unit includes enough charge for the
unit, a 15 ft. line set, and the smallest indoor coil match-up. Some
indoor coil matches may require additional charge. See tabular data
sheet provided in unit literature packet for charge requirements.
The “TOTAL SYSTEM CHARGE” must be permanently stamped on the
unit data plate.
Total system charge is determined as follows:
1.
Determine outdoor unit charge from tabular data sheet.
2.
Determine indoor coil adjustment from tabular data sheet.
3.
Calculate the line charge using the tabular data sheet if line length
is greater than 15 feet.
4.
Total system charge = item 1 + item 2 + item 3.
5.
Permanently stamp the unit data plate with the total amount of
refrigerant in the system.
Use the following charging method whenever additional refrigerant is
required for the system charge.
If a calibrated charging cylinder or accurate weighing device is avail-
able, add refrigerant accordingly. Otherwise, model-specific charging
charts are provided on the access panel of the unit. If mix matched TXV
indoor coils are used with these models, the following subcooling charg-
ing method must be used. Superheat charging charts are not valid with
TXV equipped systems.
SUBCOOLING CHARGING METHOD - MIXED MATCH
COILS
The recommended subcooling is 10°F
1.
Set the system running in the cooling mode by setting the thermo-
stat at least 6°F below the room temperature.
2.
Operate the system for a minimum of 15-20 minutes.
3.
Refer to the tabular data sheet for the recommended airflow and
verify this indoor airflow (it should be about 400 SCFM per ton).
4.
Measure the liquid refrigerant pressure P and temperature T at the
service valve.
5.
Calculate the saturated liquid temperature ST from Table 2.
6.
Subcooling temperature TC = Saturated Temperature (ST) - Liquid
Temp (T).
Add charge if the calculated subcooling temperature TC in Step 6 is
lower than the recommended level. Remove and recover the refrigerant
if the subcooling TC is higher than the recommended level. See Table
2.
Check flare caps on service ports to be sure they are leak tight. DO
NOT OVERTIGHTEN (between 40 and 60 inch - lbs. maximum).
Schrader valve core MUST NOT be installed with TXV installation.
Poor system performance or system failure could result.
Do not leave the system open to the atmosphere.
Refrigerant charging should only be carried out by a qualified air
conditioning contractor.
Compressor damage will occur if system is improperly charged. On
new system installations, charge system per tabular data sheet for
the matched coil and follow guidelines in this instruction.
Example: The pressure P and temperature T measured at the liq-
uid service port is 196 psig and 90°F, respectlvely. From Table 2,
the saturated temperature for 196 psig is 100°F. The subcooling
temperature TC = 100°-90°=10°F
TABLE 2: R-22 Saturated Properties
Pressure
PSIG
Temp °F
Pressure
PSIG
Temp °F
Pressure
PSIG
Temp °F
Pressure
PSIG
Temp °F
Pressure
PSIG
Temp °F
Pressure
PSIG
Temp °F
80
48
110
64
140
78
170
91
200
101
230
111
82
49
112
65
142
79
172
91
202
102
232
112
84
50
114
66
144
80
174
92
204
103
234
112
86
51
116
67
146
81
176
93
206
103
236
113
88
52
118
68
148
82
178
94
208
104
238
114
90
54
120
69
150
83
180
94
210
105
240
114
92
55
122
70
152
84
182
95
212
105
242
115
94
56
124
71
154
84
184
96
214
106
244
115
96
57
126
72
156
85
186
97
216
107
246
116
98
58
128
73
158
86
188
97
218
107
248
117
100
59
130
74
160
87
190
98
220
108
250
117
102
60
132
75
162
88
192
99
222
109
252
118
104
61
134
76
164
88
194
99
224
109
254
118
106
62
136
77
166
89
196
100
226
110
256
119
108
63
138
78
168
90
198
101
228
111
258
119