Page 30
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
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
-
ING STAGE 3
2 - Use a thermometer to accurately measure the
outdoor ambient temperature.
3 -
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
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.
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
TABLE 5
Outdoor
Coil
Entering
CIRCUIT 1 CIRCUIT 1
Dis-
charge
+10 psig
Suction
Discharge
+10 psig
Suction
244 132 236
281 134 271 146
322 136 309 148
366 138
139 399
464 141 449
TABLE 6
Outdoor
Coil
Entering
CIRCUIT 1 CIRCUIT 1
Dis-
charge
+10 psig
Suction
Discharge
+10 psig
Suction
139 139
286 140 291 140
326 141 331 141
370 142 376 143
417 144 426 146
468 146 481 148
TABLE 7
Outdoor
Coil
Entering
CIRCUIT 1 CIRCUIT 1
Dis-
charge
+10 psig
Suction
Discharge
+10 psig
Suction
139 130
283 142 296 133
321 141 336 133
370 146 389 138
417 148 141
469 492 144
TABLE 8
Outdoor
Coil
Entering
CIRCUIT 1 CIRCUIT 1
Discharge
+10 psig
Suction
Discharge
+10 psig
Suction
248 126
128 293 127
326 130 334 129
372 132 379 131
420 426 134
139 477 137
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