20
without dip tubes; cylinders with dip tubes will have a
labe l indicating this feature. For a cylinder with a dip
tube, place the cylinder in the upright position (access
valve at the top) when removing liquid refrigerant for
charging. For a cylinder without a dip tube, invert the
cylinder (access valve on the bottom) when removing
liquid refrigerant.
Because Puron (R--410A) refrigerant is a blend, it is strongly
recommended that refrigerant always be removed from the
cylinder as a liquid. Admit liquid refrigerant into the system
in the dis charge line. If addin g refrig eran t into the suctio n
line, use a commercial metering/exp an s ion device at the
gauge manifold; remove liquid from the cylinder , pass it
through the metering device at the gauge set and then pass it
into the suctio n lin e as a v apo r. D o not remo ve Puro n
(R–410A) refrigerant from the cylinder as a vapor .
Preliminary Charge —
Before starting the unit, charge R-410A liquid refrigerant
into the high side of each 38AU circuit through the liquid
service valve(s). The amount of refrigerant added must be
at least 80% of the operating charge listed in Tables 5 or 6
for LINEAR line length LESS the factory charge quantity
(if factory shipping charge has not been removed). See
example below.
Note: See “Adjust Re frigerant Charge” on pa ge 27 for
details on refrigerant charge adjustment. Be sure tha t al l
condenser fans are operating and that the HGBP solenoid
valve (if the unit has the factory installed hot gas bypass
option) is de--activated while charging the unit.
Allow high and low side pressures to equalize. If pressures
do not equalize rea dily, charge R-410A vapor (using spe-
cial service manifold with expansion device) into the suc-
tion line service port for the low side of system to assure
charge in the evapora tor. Refer to GTAC II, Module 5,
Charging, Recove r, Recycling, and Reclamation for liquid
charging procedures.
Example:
38AUD*25 (RTPF)
60-ft (18.3 m) linear line length
Equivalent line length 90-ft (27.4 m)
Liquid Lift: 20-ft (6.1 m)
Select line sizes from Table 6 (38AUD):
Liquid
1
/
2
in
Suction 1-
1
/
8
in.
Charge
Circuit 1: 23.0 lbs (at 75-ft linear length)
Circuit 2: 22.0 lbs
80% of Operating Charge:
Circuit 1: 0.80 x 23.0 = 18.4 lbs
Circuit 2: 0.80 x 22.0 = 17.6 lbs
Factory Shipping Charge: 15 lbs
Field-Charge
Circuit 1: 18.4 -- 15 = 3.4 lbs
Circuit 2: 17.6 -- 15 = 2.6 lbs
For line ar line lengths longer than 125 ft (38 m), conta ct
your local Carrier representative for system charge value.
Step 7 — Install Accessories
Accessories requiring modificati ons to uni t wiring should
be completed now. These accessories may include Winter
Start controls and Low Ambient controls. Refer to the
instructions shipped with the accessory.
Step 8 — Complete Electrical Connections
ELECTRICAL SHOCK HAZARD
Failure to follow this warning could result in personal
injury or death.
Do not use gas pi ping as an el ectrical ground. Unit
cabi net must have an uninterrupted, unbroke n
electrical ground to minimize the possibility of
personal injury if an electrical fault should occur. This
ground may consist of electri cal wire connected to
unit ground l ug in control compartment, or conduit
approved for e lectrical 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.
!
WARNING
Note: Check all factory and field electrical connections
for tightness. Field-supplied wiring shall conform with the
limitations of 63F(33C) rise.
Field Power Supply —
If equipped with optiona l Powered Convenience Outl et:
The power source leads to the convenienc e outl et’s
transformer primary are not factory connected. Installer
must connect these leads according to required operation
of the convenience outlet. If an always-energized
conveni ence outlet operation is desired, connect the
source leads to the line side of the unit-mounted
disconnec t. (Check with local codes to ensure this method
is acceptable in your area.) If a de-energize via unit
disconnec t switch operation of the convenience outlet is
desired, connect the source leads to the load side of t he
unit disconnect. On a unit without a unit-mounted
disconnec t, connect the source leads to compressor
contactor C and indoor fan contactor IFC pressure lugs
with unit field power leads..
Field power wires are connected to th e unit at line-side
pressure lugs on compressor contactor C and TB1 (see
wiring diagram label for control box component
arrangement) or at factory-installed option non-fused
disconnect switch. Max wire size is #4 AWG (copper only).
Note: TEST LEADS - Unit may be equipped with short
lea ds (pigtails) on the field line connection points on
conta ctor C or optional disconnect switch. These leads are
for factory run-test purposes only; remove and discard
before connecting field power wires to unit connection
points. Make field power connect ions directly to line
connec tion pressure lugs only.
38AU
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