Carrier Gemini 38AU07 Series Installation Instructions Manual page 22

THERMOSTAT
Install a Carrier-approved accessory thermostat according
to installation instructions included with the accessory. For
typical thermostat connections see Fig. 20 (38AUZ) and 21
(38AUD) Locate the thermostat accessory on a solid wall in
the conditioned space to sense average temperature in accor-
dance with the thermostat installation instructions.
(Note 3)
(Note 2)
(Note 2)
(Note 1)
Note 1: Connect only if thermostat requires 24-vac power source.
Note 2: Connect W1 and W2 if supplemental heaters are installed
Note 3: Y2 connection for Single Circuit/2-Stage units only
Field Wiring
Fig. 20 — Typical Remote Thermostat Connections -
38AUZ
(Note 1)
(Note 3)
(Note 3)
(Note 2)
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
Fig. 21 — Typical Remote Thermostat Connections -
38AUD
38AUZ UNIT
38AUZ(A,B) 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.
38AUZ(D,E) is a single circuit, two-stage cooling unit.
Select a two-stage cooling thermostat.
The 38AUD is a dual-circuit, two-stage cooling unit. Se-
lect a two-stage cooling thermostat.
Select a thermostat cable or equivalent single leads of dif-
ferent colors with minimum of four leads for 38AUZ(A,B) or
five leads for 38AUD/38AUZ(D,E) unit. Check the thermo-
stat 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 (Amer-
ican 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 re-
quire a junction box and splice at the thermostat.
PREMIERLINK (ACCESSORY INSTALLATION)
Refer to Installation, Start-Up and Configuration Instruc-
tions for PremierLink Retrofit Rooftop Controller for details on
connecting the PremierLink controller and its various sensors.
If the unit will be operating at 208-3-60 power, remove the
black wire (BLK) from the transformer primary connection
labeled "230" and move it to the connection labeled "208".
See Fig. 22.
Fig. 22 — Control Transformer Wiring
EXTERNAL DEVICES
The 38AU control transformers provide 24-v NEC Class 2
power sources to energize external control devices. These de-
vices will include the indoor fan motor contactor (or control
relay). These devices may also include liquid line solenoid
valve (two on 38AUD model), economizer control relay, sup-
plemental electric heater contactors or control relays and oth-
er devices selected by system designer.
Control transformer TRAN1 provides control power
through terminal R to C on the field connection terminal strip
TB for supply fan motor interlock. This source may also be
used to energize economizer control relay and electric heater
contactors or relays. Maximum available power is 20 va.
Check concurrent loadings by external control devices. If the
maximum concurrent loading exceeds 20 va, purchase and in-
stall the accessory Transformer-Relay package (available for
208/230 and 460-v units).
38AUD Only
Control transformer TRAN3 provides control power
through terminals A1 (9) and A2 (10) to C for liquid line so-
lenoids. Maximum available power is 75 va. These outputs
are switched ON/OFF by the Solenoid Valve Relays.
22