LEGEND FOR TABLES 2A AND 2B
FIELD CONTROL WIRING — Install a Carrier-approved
accessory thermostat assembly according to installation in-
structions included with the accessory. Locate thermostat as-
sembly on a solid wall in the conditioned space to sense av-
erage temperature in accordance with thermostat installation
instructions.
Route thermostat cable or equivalent single leads of col-
ored wire from subbase terminals to low-voltage connec-
tions on unit (shown in Fig. 8) as described in Steps 1 through
4 below.
NOTE: For wire runs up to 50 ft, use no. 18 AWG
(American Wire Gage) insulated wire (35 C minimum). For
51 to 75 ft, use no. 16 AWG insulated wire (35 C minimum).
For over 75 ft, use no. 14 AWG insulated wire (35 C mini-
mum). 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.
1. If unit is mounted on roof curb and accessory thru-the-
bottom service connections are used, route wire through
connections.
2. Pass control wires through the hole provided on unit (see
connection D in Connection Sizes table in Fig. 6).
3. Feed wire through the raceway built into the corner post
to the 24-v barrier located on the left side of the control
box. See Fig. 9. The raceway provides the UL required
clearance between the high- and low-voltage wiring.
4. Connect thermostat wires to screw terminals of low-
voltage connector (see Fig. 8).
NOTE: If thru-the-bottom power connections are used refer
to the accessory installation instructions for information on
power wiring. Refer to Fig. 6 for drilling holes in basepan.
HEAT ANTICIPATOR SETTINGS — For units with elec-
tric heat, set heat anticipator settings as shown in Table 3.
FLA — Full Load Amps
HACR — Heating, Air Conditioning
and Refrigeration
IFM — Indoor (Evaporator)
Fan Motor
LRA — Locked Rotor Amps
MCA — Minimum Circuit Amps
MOCP — Maximum Overcurrent
Protection
NEC — National Electrical Code
OFM — Outdoor (Condenser) Fan Motor
RLA — Rated Load Amps
UL — Underwriters’ Laboratories
*Heaters are field installed only.
†Heater capacity (kW) is based on heater voltage of 208 v, 240 v,
480 v, or 575 v. If power distribution voltage to unit varies from rated
heater voltage, heater kW will vary accordingly.
**Fuse or HACR circuit breaker per NEC.
NOTES:
1. In compliance with NEC requirements for multimotor and combi-
nation load and equipment (refer to NEC Articles 430 and 440),
the overcurrent protective device for the unit shall be fuse or HACR
breaker.
2. Unbalanced 3-Phase Supply Voltage
Never operate a motor where a phase imbalance in supply volt-
age is greater than 2%.
Use the following formula to determine
the percentage of voltage imbalance.
% 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 percentage of voltage imbalance:
7
% Voltage Imbalance = 100 x
457
= 1.53%
This amount of phase imbalance is satisfactory as it is below the maxi-
mum allowable 2%.
IMPORTANT: If the supply voltage phase imbalance is
more than 2% contact your local electric utility company
immediately.
3. 575-v units have UL, Canada, approval only.
LEGEND
AHA — Adjustable Heat RH — 24V Heating
Anticipator TC — Thermostat-Cooling
CC — Cooling TH — Thermostat-Heating
Compensator
Field Wiring
RC — 24V Cooling
Factory Wiring
*Used with 2-stage electric heater.
Fig. 8 — Low-Voltage Connections With
or Without Economizer or Two-Position
Damper
10
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