Carrier 48HDT - Manual (Page 19)

Fig. 35 — Condenser Air Fan Adjustment
Lubrication
COMPRESSORS — Each compressor is charged
with correct amount of oil at the factory.
FAN MOTOR BEARINGS — No lubrication of
condenser or evaporator fan motors is required for
first 5 years of operation. Annually thereafter, clean
and repack bearings with a suitable bearing grease.
Condenser Air Fan Adjustment (Fig. 35) — Shut
off unit power supply. Remove condenser fan
assembly (grille, motor, motor cover and fan) and
loosen fan hub setscrews. Adjust fan height as
shown in Fig. 35. Tighten setscrews and replace
condenser fan assembly.
Manual Outdoor Air Damper (Downshot Units
Only) — If outdoor air damper blade adjustment is
required, see Optional Manual Outdoor Air
Damper Section.
Economizer Adjustment (Downshot Units) —
Refer to Economizer section under Installation.
Refrigerant Charge — Amount of refrigerant
charge is listed on unit nameplate (also refer to
Table 1). Refer to Carrier Standard Service Tech­
niques Manual, Chapter 1, Refrigerants.
Unit panels must be in place when unit is oper­
ating during charging procedure.
NO CHARGE — Use standard evacuating tech­
niques. After evacuating system, weigh in the speci­
fied amount of refrigerant. (Refer to Table 1.)
LOW CHARGE COOLING — Using Cooling
Charging Chart, Fig. 36 through 41, vary refrigerant
until the conditions of the chart are met. Note the
charging chart is different from type normally used.
Chart is based on charging the units to the correct
superheat for the various operating conditions.
Accurate pressure gage and temperature sensing
device are required. Connect the pressure gage 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 (maximum 3750;
minimum 2250).
TO USE COOLING CHARGING CHART ^
Take the outdoor ambient temperature and read the
suction pressure gage. Refer to chart to determine
what suction temperature should be. If suction tem­
perature is high, add refrigerant. If suction tempera­
ture is low, carefully blow some of the charge. Re­
check the suction pressure as charge is adjusted.
Example; (Fig. 40)
Outdoor Temperature........................................... 85 F
Suction Pressure............................................. 70 psig
Suction Temperature should be............................52 F
(Suction Temperature may vary ± 5 F.)
(A
<
O
g 620-
Q l
O
=i
^ 551
iii
tr
§483
iij
L.
: 345
276
o 90
80
60
50
207 30
OUTDOOR TEMP
(F) (C)
115 46
105 41
95 35
85 29
75 24
1 1 1 1
65 18
20 30 40 50 60 70
SUCTION LINE TEMPERATURE (F)
-I 4 10 16 21
SUCTION LINE TEMPERATURE (C)
Fig. 36 — Cooling Charging Chart;
48LDT004
<
w620 <
0
.
o
551
] 483
^414
:345-
276-
80
? 70
60
50
40
207 30
(F) (C)
115 46
105 41
1 1 1 1 1
Mi tr
95 35
M i l l
8 5 2 9
7 5 2 4
1 1 1 1 1
6 5 1 8
20 3 0 40 50 60 70
SUCTION LINE TEMPERATURE (F)
-I 4 10') 16 21
SUCTION LINE TEMPERATURE (C)
Fig. 37 — Cooling Charging Chart;
48HDT,LDT005
19