Carrier 38AU - Manual (Page 14)

14
Fig. 8 — Location of Sight Glass(es) and Filter Driers
Typical 38AUD Systems
Fig. 9 — Typical Piping Connection Assembly
EVACUATION/DEHYDRATION — Evacuate and dehydrate
the connected refrigeration system(s) (excluding the 38AU
unit) to 500 microns using a two-stage vacuum pump attached
to the service ports outside the 38AU service valves, following
description in GTAC II, Module 4, System Dehydration.
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.
Allow high and low side pressures to equalize. If pressures do
not equalize readily, charge R-410A vapor (using special
service manifold 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 Reclamation for liquid charging procedures.
Example:
38AUZ*08
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 5 (38AUZ):
Liquid 1 /
2
in
Suction 1- 1 /
8
in.
Charge 12.9 lbs (at 75-ft linear length)
80% of Operating Charge:
0.80 x 12.9 = 10.3 lbs
Factory Shipping Charge: 4.9 lbs
Field-charge quantity: 10.3 lbs – 4.9 lbs = 5.4 lbs
For applications with linear line lengths greater than 100 ft
(30.5 m), contact your local Carrier representative.
Step 6 — Install Accessories
Accessories requiring modifications to unit wiring should be
completed now. These accessories may include Winter Start
controls, Low Ambient controls, phase monitor, Compressor
LOCout. Refer to the instructions shipped with the accessory.
Step 7 — Complete Electrical Connections
NOTE: Check all factory and field electrical connections
for tightness. Field-supplied wiring shall conform with the
limitations of 33°C (63°F) rise.
Field Power Supply —
If equipped with optional Powered Convenience Outlet: The
power source leads to the convenience outlet's transformer pri-
mary are not factory connected. Installer must connect these
leads according 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 and indoor fan contactor IFC
pressure lugs with unit field power leads.
All units are factory wired for the voltage shown on the name-
plate. Refer to unit label diagram for additional information.
Field power wires are connected to the unit at line-side pres-
sure lugs on compressor contactor C and TB1 (see wiring dia-
gram label for control box component arrangement) or at facto-
ry-installed option non-fused disconnect switch. Use copper
conductors only.
UNIT OPERATION AND SAFETY HAZARD
Failure to follow this warning could cause personal injury,
death and/or equipment damage.
Puron® (R-410A) refrigerant systems operate at higher
pressures than standard R-22 systems. Do not use R-22
service equipment or components on Puron refrigerant
equipment.
INDOOR
COIL CKT 2
AIRFLOW
SUCTION
CIRCUIT B
SUCTION
CIRCUIT A
AIRFLOW
15 DIAMS
MIN 10
DIAMS
8 DIAMS
MIN
TXV
SENSING
BULB
EQUALIZER LINE
SIGHT
GLASSES
TXV
CKT B
FILTER
DRIERS
DROP CONTROL
SOLENOID VALVE
CIRCUIT B
FLOW
DROP CONTROL
SOLENOID VALVE
CIRCUIT A
FLOW
TXV
SENSING
BULB
TXV
CKT A
8 DIAMS
MIN
15 DIAMS
MIN 10
DIAMS
Dual Circuit Coil Piping Configuration
For two circuit condensing units
LEGEND
TXV — Thermostatic Expansion Valve
Factory
High-Flow
Access Port
Service Valve
with Stem Cap
Field Service
Access Port
(Schrader core)
Sweat
Connection
ELECTRICAL SHOCK HAZARD
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 local electrical codes or in absence of
local codes, it is recommended that the U.S.A. standard
ANSI/NFPA 70, National Electrical Code (NEC), be
followed.