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IV- SYSTEMS SERVICE CHECKS
WARNING
Refrigerant can be harmful if it is inhaled. Refrigerant
must be used and recovered responsibly.
Failure to follow this warning may result in personal
injury or death.
A-Charging
WARNING-Do not exceed nameplate charge under
any condition.
This unit is factory charged and should require no further
adjustment. If the system requires additional refrigerant,
reclaim the charge, evacuate the system, and add re-
quired nameplate charge.
NOTE - System charging is not recommended below 60°F
(15°C). In temperatures below 60°F (15°C) , the charge
must be weighed into the system.
If weighing facilities are not available, or to check the
charge, use the following procedure:
1 - Attach gauge manifolds to discharge and suction
lines. With the economizer disabled, operate the unit
in cooling mode at high speed using the following
mobile service app menu path:
SERVICE > COMPONENT TEST > COOLING > COOL-
ING STAGE 3
2 - Use a thermometer to accurately measure the
outdoor ambient temperature.
3 - Apply the outdoor temperature to TABLE 5 through
TABLE 9 to determine normal operating pressures.
Pressures are listed for sea level applications at
80F dry bulb and 67F wet bulb return air.
4 - Compare the normal operating pressures to
the pressures obtained from the gauges. Minor
variations 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. Correct any system problems before
proceeding.
5 - If discharge pressure is high, remove refrigerant
from the system. If discharge pressure is low, add
refrigerant to the system.
•
Add or remove charge in increments.
•
Allow the system to stabilize each time refrigerant
is added or removed.
6 - Use the following subcooling method along with the
normal operating pressures to confirm readings.
Outdoor
Coil
Entering
Air Temp ⁰ F
65
75
85
95
105
115
Outdoor
Coil
Entering
Air Temp ⁰ F
65
75
85
95
105
115
Outdoor
Coil
Entering
Air Temp ⁰ F
65
75
85
95
105
115
Outdoor
Coil
Discharge
Entering
Air Temp ⁰ F
65
75
85
95
105
115
Page 30
TABLE 5
LDT078 - 581118-01
CIRCUIT 1
Dis-
Suction
Discharge
charge
+5 psig
+10 psig
+10 psig
244
132
236
281
134
271
322
136
309
366
138
354
415
139
399
464
141
449
TABLE 6
LDT092 - 581119-01
CIRCUIT 1
Dis-
Suction
Discharge
charge
+5 psig
+10 psig
+10 psig
250
139
253
286
140
291
326
141
331
370
142
376
417
144
426
468
146
481
TABLE 7
LDT102 - 581120-01
CIRCUIT 1
Dis-
Suction
Discharge
charge
+5 psig
+10 psig
+10 psig
245
139
258
283
142
296
321
141
336
370
146
389
417
148
435
469
151
492
TABLE 8
LDT120 - 581121-01
CIRCUIT 1
Suction
Discharge
+10 psig
+5 psig
+10 psig
248
126
256
285
128
293
326
130
334
372
132
379
420
135
426
475
139
477
CIRCUIT 1
Suction
+5 psig
145
146
148
150
152
154
CIRCUIT 1
Suction
+5 psig
139
140
141
143
146
148
CIRCUIT 1
Suction
+5 psig
130
133
133
138
141
144
CIRCUIT 1
Suction
+5 psig
125
127
129
131
134
137
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