Carrier 48TJD008-014 Installation, Start-Up And Service Instructions Manual page 26

Single-package rooftop heating/cooling units
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Condenser-Fan Adjustment (Fig. 40)
1. Shut off unit power supply.
2. Remove condenser-fan assembly (grille, motor, motor cover,
and fan) and loosen fan hub setscrews.
3. Adjust fan height as shown in Fig. 40.
4. Tighten setscrews and replace condenser-fan assembly.
48TJ UNIT VOLTAGE
208/230 V
460 V and 575 V
Fig. 40 — Condenser-Fan Adjustment
Manual Outdoor-Air Damper —
blade is required, see Manual Outdoor-Air Damper section
on page 11.
Economizer Adjustment —
mizer sections on pages 12 and 15.
Condenser Coil Grille —
factory-installed. No adjustments are required.
Refrigerant Charge —
is listed on unit nameplate (also refer to Table 1). Refer to
Carrier GTAC 2-5 Charging, Recovery, Recycling, and Rec-
lamation training manual and the following procedures.
Unit panels must be in place when unit is operating dur-
ing charging procedure.
NO CHARGE — Use standard evacuating techniques. After
evacuating system, weigh in the specified amount of refrig-
erant (refer to Table 1).
LOW CHARGE COOLING — Using Cooling Charging
Charts, Fig. 41-44, vary refrigerant until the conditions of
the appropriate chart are met. Note the charging charts are
different from the type normally used. The charts are based
on charging the units to the correct superheat for the various
operating conditions. Accurate pressure gage and tempera-
ture sensing device are required. Connect the pressure gage
FAN HEIGHT ''A'' (in.)
2.75
3.50
If outdoor-air damper
Refer to Optional Econo-
Condenser coil grille is shipped
Amount of refrigerant charge
to the service port on the suction line. Mount the tempera-
ture sensing device on the suction line and insulate it so that
outdoor ambient temperature does not affect the reading. Indoor-
air cfm must be within the normal operating range of the
unit.
TO USE COOLING CHARGING CHART — Take the out-
door ambient temperature and read the suction pressure gage.
Refer to appropriate chart to determine what suction tem-
perature should be. If suction temperature is high, add re-
frigerant. If suction temperature is low, carefully recover some
of the charge. Recheck the suction pressure as charge is ad-
justed. Example (Fig. 44, Circuit 2):
Outdoor Temperature . . . . . . . . . . . . . . . . . . . . . . . . . . 85 F
Suction Pressure . . . . . . . . . . . . . . . . . . . . . . . . . . . 74 psig
Suction Temperature should be . . . . . . . . . . . . . . . . . . 56 F
(Suction temperature may vary ± 5 F.)
If Chargemaster charging device is used, temperature and
pressure readings must be accomplished using the charging
charts.
Fig. 41 — Cooling Charging Chart; 48TJ008
26

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