Step 6 - Make Electrical Connections - Bryant DuraPac 558F Installation & Service Instructions Manual

Fig. 11 — Make Electrical Connections
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%.
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.
Use the following formula to determine the percentage of
voltage imbalance.
Percentage of Voltage Imbalance
max voltage deviation from average voltage
= 100 x
average voltage
EXAMPLE: Supply voltage is 460-3-60.
AB = 452 v
BC = 464 v
AC = 455 v
Average Voltage =
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:
Percentage of Voltage Imbalance = 100 x
455 + 464 + 455
3
1371
=
3
= 457
7
457
= 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.
TB1 MAXIMUM WIRE SIZE
UNIT
558F
All
LEGEND
EQUIP — Equipment
GND — Ground
kcmil — Thousand Circular Mils
NEC — National Electrical Code
TB — Terminal Block
Fig. 12 — Field Power Wiring Connections
THERMOSTAT ASSEMBLY
REMOVABLE JUMPER
RC Y1
RH
R
Y1
UNIT LOW-VOLTAGE CONNECTIONS
Fig. 13 — Field Control Thermostat Wiring
— 10 —
VOLTAGE
208/230 460
350 kcmil 2/0
Y2 W1
W2 G C
W2 C
Y2 W1 G
L
X
X