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Unit Start−Up and Operation
Each 13CHA packaged cooling unit is factory−charged with
R−22 refrigerant. The compressor is hermetically sealed,
internally sprung and base−mounted with rubber−insulated
hold−down bolts.
Pre−Start Check List:
1 − Make sure refrigerant lines do not rub against the cabi-
net or each other.
2 − Inspect all electrical wiring, both factory− and field−
installed, for loose connections.
3 − Check voltage at the disconnect switch. Voltage must
be within the range listed on the unit nameplate. If not,
consult power company and have voltage condition
corrected before starting unit.
4 − Recheck voltage with unit running. If power is not with-
in the range listed on the unit nameplate, stop the unit
and consult the power company. Check unit amper-
age. Refer to unit nameplate for correct running amps.
5 − Make sure filter is in place before unit start−up.
6 − Before placing the unit into full operation, energize the
unit for three false starts. Energize the compressor
just long enough for it to make a few revolutions, wait
five to seven minutes before repeating a second and
third time.
Cooling Sequence of Operation
When the thermostat calls for cooling, the R" to Y" circuit
is closed to energize the compressor contactor. The
contactor brings on both the compressor and outdoor fan.
The thermostat also closes the R" to G" circuit to energize
the circulating air blower. When the cooling demand is
satisfied, the thermostat opens the circuits, as well as the
compressor contactor. The compressor and outdoor fan
immediately stop. The circulating air blower continues
operating through a 90−second delay.
Unit compressors have internal protection. If there is an
abnormal rise in the compressor temperature, the
protector will open and the compressor will stop.
System Performance
For maximum performance of this cooling system, the
operating temperatures and pressure should be checked
and superheat determined at Standard ARI test conditions
of 82
F outdoor temperature / 80
F indoor dry bulb / 67
F
indoor wet bulb. If superheat measured deviates from
values in table 2, refrigerant charge should be adjusted
accordingly for maximum performance.
Table 2
Suction Superheat Values
Unit Model No.
Suction Superheat
82
F OD / 80
F IDDB
/ 67
F IDWB
13CHA−24
22
F
13CHA−30
20
F
13CHA−36
20
F
13CHA−42
20
F
13CHA−48
20
F
13CHA−60
20
F
Verify system performance using table 3 as a general guide.
Table 3 should not be used for charging unit. Minor varia-
tions in these pressures may be expected due to differences
in installations. Significant differences could mean that the
system is not properly charged or that a problem exists with
some component in the system.
Used carefully, this table could serve as a useful service
guide. Data is based on 80
°
F dry bulb / 67
°
F wet bulb return
air. Allow unit operation to stabilize before taking pressure
readings.
Table 3
Normal Operating Pressures
80
°
F db / 67
°
F wb RETURN AIR
Air Temperature Entering Outdoor Coil (
°
F)
UNIT
PRESSURE
65
70
75
80
82
85
90
95
100
104
105
110
115
13CHA−24
78
80
82
84
85
86
88
90
91
92
92
93
94
13CHA−30
78
79
81
82
83
84
85
87
87
88
88
89
90
13CHA−36
Suction
79
80
81
83
83
84
85
86
87
88
88
89
90
13CHA−42
Suction
75
76
78
79
80
81
83
84
87
89
89
90
91
13CHA−48
76
77
79
80
81
82
83
85
85
86
86
88
91
13CHA−60
78
79
81
82
83
84
85
87
88
89
89
91
92
13CHA−24
131
146
161
176
182
191
207
221
238
250
250
268
286
13CHA−30
132
148
164
181
187
197
213
229
246
259
259
277
295
13CHA−36
Liquid
146
161
176
191
197
206
221
236
250
262
262
280
298
13CHA−42
Liquid
129
144
159
175
181
190
205
221
236
248
248
267
286
13CHA−48
131
146
161
177
183
193
208
223
240
253
253
272
291
13CHA−60
143
159
175
191
197
206
221
238
252
264
264
283
302
