Step 6 — Make Electrical Connections
FIELD POWER SUPPLY — Unit is factory wired for volt-
age 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 and 5) to connections as shown on unit wir-
ing diagram and Fig. 11.
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%.
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 compressor failure.
Use the following formula to determine the percentage of
voltage imbalance.
Percentage of Voltage Imbalance
= 100 x
max voltage deviation from average voltage
average voltage
EXAMPLE: Supply voltage is 460-3-60.
AB = 452 v
BC = 464 v
AC = 455 v
Average Voltage =
452 + 464 + 455
3
=
1371
3
= 457
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 the percentage of voltage imbalance:
Percentage of Voltage Imbalance = 100 x
7
457
= 1.53%
This amount of phase imbalance is satisfactory as it is be-
low the maximum allowable 2%.
IMPORTANT: If the supply voltage phase imbalance
is more than 2%, contact your local electric utility com-
pany immediately.
Unit failure as a result of operation on improper line volt-
age or excessive phase imbalance constitutes abuse and may
cause damage to electrical components.
FIELD CONTROL WIRING — Install a Carrier-approved
accessory thermostat assembly 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 sub-
base terminals through conduit in unit to low-voltage con-
nections as shown on unit label wiring diagram and in
Fig. 12.
NOTE: For wire runs up to 50 ft, use no. 18 AWG insul-
ated 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 ther-
mostat and will require a junction box and splice at the
thermostat.
Set heat anticipator settings as indicated in Table 3. Set-
tings may be changed slightly to provide a greater degree of
comfort for a particular installation.
Refer to accessory remote control instructions as
required.
Fig. 10 — Condensate Drain Piping Details
TB1 MAXIMUM WIRE SIZE
UNIT
50TJ
VOLTAGE
208/230,380 460 575
All 350 kcmil 2/0 2/0
LEGEND
EQUIP — Equipment NEC — National Electrical
GND — Ground Code
kcmil — Thousand Circular TB — Terminal Block
Mils
Fig. 11 — Field Power Wiring Connections
UNIT LOW-VOLTAGE CONNECTIONS
Fig. 12 — Field Control Thermostat Wiring
8
To Next Page
Loading...
