Carrier 38AUQ appendix Field Control Wiring, Thermostat

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.

COVER – WHILE-IN-USE	RECEPTACLE
WEATHERPROOF
	NOT INCLUDED

BASE PLATE FOR

GFCI RECEPTACLE

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.

R

G

Y1

O/B/Y2

(Notes 1, 2)

W1

W2

(Note 4)

C

(Note 3)

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

Fig. 13 — Typical Remote Thermostat Connections

13