Carrier 38AUQ User Manual

Page 13

Press the gasket over the screw heads. Slip the backing plate

over the screw heads at the keyhole slots and align with the

gasket; tighten the two screws until snug (do not over-tighten).
Mount the weatherproof cover to the backing plate as shown in

Fig. 12. Remove two slot fillers in the bottom of the cover to

permit service tool cords to exit the cover. Check for full

closing and latching.

Fig. 12 — Weatherproof Cover Installation

All Units —
Voltage to compressor terminals during operation must be

within voltage range indicated on unit nameplate. See Table 8.

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 Table 8, Note 5 (see pages 14) 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 —
38AUQ unit control voltage is 24 v. See Fig. 19 for typical

field control connections and the unit’s label diagram for field-

supplied wiring details. Route control wires to the 38AUQ 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. Fig. 13 depicts typical connections to a Carrier 40RUQ

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 38AUQ 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. For

complete economizer function, select a two—stage cooling

thermostat. Locate the thermostat accessory on a solid wall in

the conditioned space to sense average temperature in

accordance with the thermostat installation instructions.
If the thermostat contains a logic circuit requiring 24-v power,

use a thermostat cable or equivalent single leads of different

colors with minimum of five leads. If the thermostat does not

require a 24-v source (no “C” connection required), use a

thermostat cable or equivalent with minimum of four leads.

Check the thermostat installation instructions for additional

features which might require additional conductors in the

cable.
For wire runs up to 50 ft. (15 m), use no. 18 AWG (American

Wire Gage) insulated wire (35°C minimum). For 50 to 75 ft.

(15 to 23 m), use no. 16 AWG insulated wire (35°C minimum).

For over 75 ft. (23 m), 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. 13 — Typical Remote Thermostat Connections

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 W2 if supplemental heater installed

Field Wiring

O/B/Y2

(Notes 1, 2)

(Note 3)

(Note 4)