Carrier 38AQ Specifications download pdf (Page 12)

Perloc_flcodelequimments,provideanadequatefuseddis-

connectswitchwithinsightofunitandoutofreachofchildren.

Provisionforlockingswitchopen(off)isadvisabletoplevent

powerfrombeingturnedonwhileunitisbeingserviced.Tile

disconnectswitch,luses,andfieldwiringmustcomplywith

localrequilements.RefertoTable7forelectric_fldata.

POWERWIRING- All powerwilingmustcomplywith

applicableloc_drequirements.Run powerwires fiom

disconnectswitchthroughunitpoweropeningandconnectto

terminalblockinsidetheunitcontrolbox.SeeFig.8-13.

UNBALANCED3-PHASESUPPLYVOLTAGE-- Never

operateamotorwhereaphaseimbalanceinsupplyvoltageis

gleaterthan2%.Usethefollowingformulatodeterminethe

percentageofvoltageimbalance:

%Voltagehnbalance:

= 100x max voltage deviation from average voltage

average voltage

EXAMPLE: Supply voltage is 460-3-60.

AB = 452 v

BC = 464 v

AC = 455 v

h B ¢

@ Average Voltage - 452 + 464 + 455

= 457 v

Determine maximum deviation from average voltage:

(AB) 457 - 452 = 5 v

(BC) 464 - 457 = 7 v

(AC) 457 - 455 = 2 v

Maximum deviation is 7 v. Determine percentage of voltage

imbahmce:

% Voltage hnbalance = 100 x

= 1.53%

This amount of phase imbalance is satisfactory as it is

below the maximum allowable of 2%.

IMPORTANT: Contact your local electric utility

company immediately if the supply voltage phase

imbalance is more than 2%.

Unit cabinet must have an uninterrupted, unbroken electri-

cal ground to minimize the possibility of personal injury if

an electrical fault should occm: This ground may consist of

electrical wire connected to unit ground lug in control com-

p_utment, or conduit approved for electrical ground when

installed in accordance with NEC (National Electrical

Code) (U.S.A.), ANSI/NFPA (American National Stan-

dards Institute/National Fire Protection Association)

(U.S.A.), and loc_d electric_d codes. Failure to follow this

w_u'ning could result in the installer being liable for per-

sonal injury of others.

IMPORTANT: Operation of unit on improper power ]

supply voltage or with excessive phase imbahmce con-

Istitutes abuse and is not covered by Carrier warranty.

GENERAL WIRING NOTES (See Fig. 8-13)

I. A crankcase heater is wired in the control circuit so it is

always operable as long as power supply disconnect is

on, even if any safety device is open or unit stop/stmt

switch is off.

2. The power-cimuit field supply disconnect should never be

open except when unit is being seia'iced or is to be down

fi_r a prolonged period When operation is resumed,

crunkcase heater should be eneqked fi_r 24 hours b@re

start-up. [_ s3_tem is to be shut down fi_r a prolonged

t)eiqod, it is recommended Nat the suction and dischaiig, e

vah'es be closed m prevent an (_rcessive accumulation of

refiqgerant in the conq)ressor oil.

3. Terminals for field power supply tue suitable for copper.

copper-clad Numinum, or aluminum conductors.

4. Cturier recommends an indoor airflow switch (field

supplied) be installed and interlocked with the outdoor

unit. This prevents the outdoor unit fi_)m operating if

indoor airflow Nils (broken Nn belt, etc.). Operafion of

the compressor in vacuum can damage bearing surfaces.

Install indoor airflow switch in a convenient location at

the indoor supply air duct and wire per Fig. 14.

CONTROL CIRCUIT WIRING -- Control voltage is 24 v.

See unit label diagram for field-supplied wiring detNls. Route

control wires through opening in unit end panel to connection

in unit control box.

CONTROL TRANSFORMER WIRING -- On multivoltage

units, check the transformer primary wiring connections. See

Fig. 9 or refer to unit label diagram.

For 38AO.ARO Units -- If unit will be operating at 400-3-50

power, remove the black wire (BLK) from the transformer pri-

mtuy connection labelled "460" and move it to the connection

labelled "400". See Fig. 9.

If unit will be operating at 208-3-60 power, remove black

wire (BLK) from the transformer primtuy connection labelled

"230" and move it to the connection labelled "208". See Fig. 9.

For 38AQS Units -- Transformers no. 1 and 2 are wired for a

230-v unit. |fa 208/230-v unit is to be mn with a 208-v power

supply, the transformers must be rewiled as follows:

1. Remove cap from red (208 v) wire.

2. Remove cap from orange (230 v) spliced wile.

3. Replace orange wire with red wile.

4. Recap both wires.

IMPORTANT: BE CERTAIN UNUSED WIRES ARE ]

CAPPED. Failure to do so may damage the transforlner.

Duplex 38AQS.ARQ with 40RMQ024 or 40RMQ028 -- In

order to properly connect two heat pump condensing units to a

single 40RMQ packaged air handler, it is necessary to add

field-supplied Fan Coil Relay Board(s), P/N 33ZCRLYBRD.

Relay botud(s) no. 1 and no. 2 should be installed in the control

box of condensing unit.

IMPORTANT: The common (COM) terminals from the

fan coil relay board(s) must be connected to the 'C' ter-

minal in condensing unit 'A'.

Route thermostat cable or equiwdent single leads of no. 18

AWG (American Wire Gage) colored wire from subbase termi-

nals through conduit in unit to low-voltage connections as

shown on unit wiring diagram and Fig. 12 and 13.

NOTE: For wire runs up to 50 ft, use no. 18 AWG insulated

wire (35 C minimum). For 51 to 75 ft, use no. 16 AWG insu-

lated wire (35 C minimum). For over 75 ft, use no. 14 AWG

insulated wire (35 C minimum). All wire huger than no. 18

AWG c_mnot be directly connected to the thermostat and will

require a junction box and a splice at the thermostat.

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Carrier 38AQ Specifications Page 12

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