Carrier 38AUD*12 Series, Installation, Start-Up And Service Instructions Manual, Page: 17 / 80

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Fig. 14 — Weatherproof Cover Installation
All Units —
Voltage to compressor terminals during operation must be
within voltage range indicated on unit nameplate. See Tables
10 and 11. On 3-phase units, voltages between phases must be
balanced within 2% and the current within 10%. Use the
formula shown in the legend for Tables 10 and 11, Note 5 (see
page 19) to determine the percent of voltage imbalance.
Operation on improper line voltage or excessive phase
imbalance constitutes abuse and may cause damage to
electrical components. Such operation would invalidate any
applicable Carrier warranty.
Field Control Wiring — 38AU unit control voltage is 24 v.
See Figs 23 and 24 for typical field control connections and the
unit’s label diagram for field-supplied wiring details. Route
control wires to the 38AU unit through the opening in unit’s
end panel to the connections terminal board in the unit’s
control box.
Remainder of the system controls connection will vary
according to the specific construction details of the indoor
section (air handler or packaged fan coil). Figs 15 (38AUZ)
and 16 (38AUD) depict typical connections to a Carrier 40RU
fan coil unit. Plan for field connections carefully and install
control wiring correctly per the project plan. Additional
components and supplemental transformer accessory may be
required.
The 38AU unit requires an external temperature control device.
This device can be a thermostat (field-supplied) or a
PremierLink controller (available as a field-installed accessory,
for use on a Carrier Comfort Network or as a stand alone
control).
Thermostat —
Install a Carrier-approved accessory thermostat according to
installation instructions included with the accessory. Locate the
thermostat accessory on a solid wall in the conditioned space to
sense average temperature in accordance with the thermostat
installation instructions.
38AUZ Unit – 38AUZ unit is a single-stage cooling unit. If no
economizer function is required, select a single-stage cooling
thermostat. If an integrated economizer function is required,
select a two—stage cooling thermostat.
38AUD Unit – 38AUD unit is a two-stage cooling unit. Select
a two-stage cooling thermostat.
Select a thermostat cable or equivalent single leads of different
colors with minimum of four leads for 38AUZ unit or five
leads for 38AUD units. Check the thermostat installation
instructions for additional features which might require
additional conductors in the cable.
For wire runs up to 15 m (50 ft.), use no. 18 AWG (American
Wire Gage) insulated wire (35°C minimum). For 15 to 23 m
(50 to 75 ft.), use no. 16 AWG insulated wire (35°C minimum).
For over 23 m (75 ft.), use no. 14 AWG insulated wire (35°C
minimum). All wire sizes larger than no. 18 AWG cannot be
directly connected to the thermostat and will require a junction
box and splice at the thermostat.
PremierLink (accessory installation) – Refer to Form 33CS-
58SI for details on connecting the PremierLink controller and
its various sensors.
Fig. 15 — Typical Remote Thermostat Connections
— 38AUZ
Fig. 16 — Typical Remote Thermostat Connections
— 38AUD
RECEPTACLE
NOT INCLUDED
COVER – WHILE-IN-USE
WEATHERPROOF
BASE PLATE FOR
GFCI RECEPTACLE
Note 1: Typical multi-function marking. Follow manufacturer’s configuration
instructions to select Y2.
Note 2: Y2 to economizer required on single-stage cooling units when
integrated economizer function is desired
Note 3: Connect only if thermostat requires 24-vac power source.
Note 4: Connect W1 and W2 if supplemental heaters are installed
Field Wiring
R
Y1
G
O/B/Y2
C
W2
W1
(Notes 1, 2)
(Note 3)
(Note 4)
(Note 4)
Note 1: Typical multi-function marking. Follow manufacturer’s configuration
instructions to select Y2.
Note 2: Connect only if thermostat requires 24-vac power source.
Note 3: Connect W1 and W2 if supplemental heaters are installed
Field Wiring
R
Y1
G
O/B/Y2
C
W2
W1
(Notes 1)
(Note 3)
(Note 3)
(Note 3)