Bryant 558F User Manual

Page 10

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VI. STEP 6 — MAKE ELECTRICAL CONNECTIONS

A. Field Power Supply

Unit is factory wired for voltage shown on nameplate.

When installing units, provide a disconnect, per NEC
(National Electrical Code) requirements, of adequate size
(Table 2).

All field wiring must comply with NEC and local
requirements.

Route power lines through control box access panel or unit
basepan (Fig. 4-6) to connections as shown on unit wiring
diagram and Fig. 12.

Operating voltage to compressor must be within voltage
range indicated on unit nameplate. On 3-phase units, volt-
ages between phases must be balanced within 2% and the
current must be balanced within 10%.

Use the following formula to determine the percentage of
voltage imbalance.

Percentage of Voltage Imbalance

EXAMPLE: Supply voltage is 460-3-60.

AB = 452 v
BC = 464 v
AC = 455 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 percent voltage imbalance:

= 1.53%

This amount of phase imbalance is satisfactory as it is below
the maximum allowable 2%.

IMPORTANT: If the supply voltage phase imbalance is
more than 2%, contact your local electric utility company
immediately.

Unit failure as a result of operation on improper line voltage
or excessive phase imbalance constitutes abuse and may
cause damage to electrical components.

B. Field Control Wiring

Install a Bryant-approved accessory thermostat assembly or
light commercial thermidistat for units equipped with Per-
fect Humidity™ Dehumidification option, according to the
installation instructions included with the accessory. Locate
thermostat assembly on a solid wall in the conditioned space
to sense average temperature.

Route thermostat cable or equivalent single leads of no. 18
AWG (American Wire Gage) colored wire from subbase ter-
minals through conduit in unit to low-voltage connections as
shown on unit label wiring diagram and in Fig. 13.

NOTE: For wire runs up to 50 ft, use no. 18 AWG insulated
wire (35 C minimum). For 50 to 75 ft, use no. 16 AWG
insulated wire (35 C minimum). For over 75 ft, use no. 14
AWG insulated wire (35 C minimum). All wire larger than
no. 18 AWG cannot be directly connected to the thermostat
and will require a junction box and splice at the thermostat.

Set heat anticipator settings as indicated in Table 3. Settings
may be changed slightly to provide a greater degree of com-
fort for a particular installation.

CAUTION: The correct power phasing is critical in

the operation of the scroll compressors. An incorrect
phasing will cause the compressor to rotate in the
wrong direction. This may lead to premature compres-
sor failure.

= 100 x

max voltage deviation from average voltage
average voltage

Average Voltage =

455 + 464 + 455
3

1371
3

= 457

Percentage of Voltage Imbalance = 100 x

7
457

Fig. 11 — Make Electrical Connections

TB1 MAXIMUM WIRE SIZE

LEGEND

Fig. 12 — Field Power Wiring Connections

UNIT
558F

VOLTAGE

208/230

460

All

350 kcmil

2/0

EQUIP — Equipment
GND

— Ground

kcmil

— Thousand Circular Mils

NEC

— National Electrical Code

— Terminal Block

REMOVABLE JUMPER

RED

BLU

PNK

ORN

VIO

BLK

BRN

WHT

THERMOSTAT ASSEMBLY

UNIT LOW-VOLTAGE CONNECTIONS

Fig. 13 — Field Control Thermostat Wiring