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PRELIMINARY CHARGE
Before starting the unit, charge R-410A liquid refrigerant into the
high side of each 38AUQ circuit through the liquid service
valve(s). The amount of refrigerant added must be at least 80% of
the operating charge listed in Table 4 for LINEAR line length
LESS the factory charge quantity (if factory shipping charge has
not been removed). See the following example.
Allow high and low side pressures to equalize. If pressures do not
equalize readily, charge R-410A vapor (using special service man-
ifold with expansion device) into the suction line service port for
the low side of system to assure charge in the evaporator. Refer to
GTAC II, Module 5, Charging, Recover, Recycling, and Reclama-
tion for liquid charging procedures.
Example:
38AUQ*25
60 ft (18.3 m) linear line length
Equivalent line length 90 ft (27.4 m)
Cooling Liquid Lift: 20 ft (6.1 m)
Select line sizes from Table 4 (38AUQ):
Liquid 1/2 in. (provides liquid lift to 24 ft (7.3 m))
Vapor 1-1/8 in.
Charge (each circuit):
1/2 in. liquid line: 30.7 lb (at 75 ft linear length)
80% of Operating Charge:
0.80 x 30.7 = 24.6 lb
Factory Shipping Charge: 9 lb
Field-Charge (each circuit):
24.6 – 9.0 = 15.6 lb
For linear line lengths longer than 125 ft (38.1 m), contact your lo-
cal Carrier representative for system charge value.
Step 6 — Install Accessories
Accessories requiring modifications to unit wiring should be com-
pleted now. These accessories may include Winter Start controls,
Low Ambient controls, phase monitor, Compressor Lockout. Re-
fer to the instructions shipped with the accessory. Additionally, for
low ambient controls, refer to Table 8.
Table 8 — Minimum Outdoor Air Operating
Temperature
PERCENT
UNIT
COMPRESSOR
CAPACITY
38AUQ*16
100
38AUQ*25
100
NOTE(S):
a. Applies to Cooling mode of operation only.
b. Wind baffles (field-supplied and field-installed) are recommended for all units
with low ambient head pressure control. Refer to Low Ambient Control Instal-
lation Instructions (shipped with accessory) for details.
MINIMUM OUTDOOR TEMP
°F (°C)
a
Head Pressure
Standard Unit
Control
b
35 (1.7)
–20 (–28.9)
35 (1.7)
–20 (–28.9)
Step 7 — Complete Electrical Connections
Failure to follow this warning could result in personal injury or
death.
Do not use gas piping as an electrical ground.
Unit cabinet must have an uninterrupted, unbroken electrical
ground to minimize the possibility of personal injury if an
electrical fault should occur. This ground may consist of
electrical wire connected to unit ground lug in control
compartment, or conduit approved for electrical ground when
installed in accordance with NEC (National Electrical Code);
ANSI/NFPA 70, latest edition (in Canada, Canadian Electrical
Code CSA [Canadian Standards Association] C22.1), and
local electrical codes.
NOTE: Check all factory and field electrical connections for tight-
ness. Field-supplied wiring shall conform with the limitations of
63°F (33°C) rise.
FIELD POWER SUPPLY
If equipped with optional Powered Convenience Outlet: The pow-
er source leads to the convenience outlet's transformer primary are
not factory connected. Installer must connect these leads accord-
ing to required operation of the convenience outlet. If an always-
energized convenience outlet operation is desired, connect the
source leads to the line side of the unit-mounted disconnect.
(Check with local codes to ensure this method is acceptable in
your area.) If a de-energize via unit disconnect switch operation of
the convenience outlet is desired, connect the source leads to the
load side of the unit disconnect. On a unit without a unit-mounted
disconnect, connect the source leads to compressor contactor C
with unit field power leads.
All units except 208/230-v units are factory wired for the voltage
shown on the nameplate. If the 208/230-v unit is to be connected
to a 208-v power supply, the control transformer must be rewired
by moving the black wire with the 1/4 in. female spade connector
from the 230-v connection and moving it to the 208-v 1/4 in. male
terminal on the primary side of the transformer. Refer to unit label
diagram for additional information.
Field power wires are connected to the unit at line-side pressure
lugs on compressor contactor C and TB1 (see wiring diagram la-
bel for control box component arrangement) or at factory-installed
option non-fused disconnect switch. Max wire size is no.4 AWG
(copper only).
NOTE: TEST LEADS - Unit may be equipped with short leads
(pigtails) on the field line connection points on contactor C or op-
tional disconnect switch. These leads are for factory run-test pur-
poses only; remove and discard before connecting field power
wires to unit connection points. Make field power connections di-
rectly to line connection pressure lugs only.
FIRE HAZARD
Failure to follow this warning could result in intermittent oper-
ation or performance satisfaction. Do not connect aluminum
wire between disconnect switch and condensing unit. Use only
copper wire. (See Fig. 8.)
12
WARNING
WARNING
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