9
Step 6 — Make Electrical Connections
FIELD POWER SUPPLY — Unit is factory wired for volt-
age shown on nameplate. Units are provided with terminal
block.
When installing units, provide a disconnect of adequate size
per local ordinances and codes (see Table 2).
All field wiring must comply with local requirements.
Route power lines through control box end panel or unit
basepan (Fig. 4 and 5) to terminal connections as shown on
unit wiring diagram and Fig. 11.
Operating voltage to compressor must be within voltage
range indicated on unit nameplate. Voltages between phases
must be balanced within 2% and the current must be balanced
within 10%.
Use the following formula to determine the percent voltage
imbalance.
Example: Supply voltage is 400-3-50.
AB = 393 v
BC = 403 v
AC = 396 v
= 397
Determine maximum deviation from average voltage:
(AB) 397 – 393 = 4 v
(BC) 403 – 397 = 6 v
(AC) 397 – 396 = 1 v
Maximum deviation is 6 v.
Determine percentage of voltage imbalance:
This amount of phase imbalance is satisfactory as it is be-
low the maximum allowable 2%.
Unit failure as a result of operation on improper line voltage
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 in-
structions included with the accessory. Locate thermostat
assembly on a solid wall in the conditioned space to sense aver-
age temperature.
Route thermostat cable or equivalent single leads of
1.0 mm
2
(no. 18 AWG [American Wire Gage, U.S.A.]) col-
ored wire from subbase terminals through conduit in unit to
low-voltage connections as shown on unit label wiring diagram
and in Fig. 12.
NOTE: For wire runs up to 15 m (50 ft), use 1.0 mm
2
(no. 18
AWG) insulated wire (35 C minimum). For 15 to 23 m (50 to
75 ft), use 1.5 mm
2
(no. 16 AWG) insulated wire (35 C mini-
mum). For over 23 m (75 ft), use 2.5 mm
2
(no. 14 AWG) insu-
lated wire (35 C minimum). All wire larger than 1.0 mm
2
(no. 18 AWG) cannot be directly connected to the thermostat
and will require a junction box and splice at the thermostat.
See Table 3 for American/European wire conversions.
Set heat anticipator settings as indicated in Table 4. Settings
may be changed slightly to provide a greater degree of comfort
for a particular installation.
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.
= 100 x
max voltage deviation from average voltage
average voltage
Average Voltage =
393 + 403 + 396
3
=
1192
3
% Voltage Imbalance = 100 x
6
397
= 1.5%
IMPORTANT: If the supply voltage phase imbalance is
more than 2%, contact your local electric utility company
immediately.
Fig. 10 — Condensate Drain Piping Details
RH
RC
Y1 Y2
W1
W2
GC
X
L
X
C
G
W2
W1Y2
Y1
R
REMOVABLE JUMPER
RED
BLU
PNK
ORN
VIO
BLK
BRN
WHT
THERMOSTAT ASSEMBLY
LEGEND
NOTE: The maximum wire size for TB1 is 70 mm
2
(2/0 AWG).
Fig. 11 — Field Power Wiring Connections
AWG —
American Wire Gage
EQUIP —
Equipment
GND —
Ground
TB —
Terminal Block
UNIT LOW VOLTAGE CONNECTIONS
Fig. 12 — Field Control Thermostat Wiring
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