Manual 2100-577C
Page
18 of 50
WIRING – MAIN POWER
Refer to the unit rating plate and/or Table 2 for wire
sizing information and maximum fuse or circuit breaker
size. Each unit is marked with a “Minimum Circuit
Ampacity”. This means that the field wiring used must
be sized to carry that amount of current. Depending
on the installed KW of electric heat, there may be
two field power circuits required. If this is the case,
the unit serial plate will so indicate. All models are
suitable only for connection with copper wire. Each
unit and/or wiring diagram will be marked “Use Copper
Conductors Only”. These instructions
must be
adhered
to. Refer to the National Electrical Code (NEC) for
complete current carrying capacity data on the various
insulation grades of wiring material. All wiring must
conform to NEC and all local codes.
The electrical data lists fuse and wire sizes (75°C
copper) for all models, including the most commonly
used heater sizes. Also shown are the number of field
power circuits required for the various models with
heaters.
The unit rating plate lists a “Maximum Time Delay
Relay Fuse” or circuit breaker that is to be used with
the equipment. The correct size must be used for
proper circuit protection, and also to assure that there
will be no nuisance tripping due to the momentary high
starting current of the compressor motor.
The disconnect access door on this unit may be locked
to prevent unauthorized access to the disconnect.
The field wiring connections are located behind the top
panel in the circuit breaker panel. The return air panel
must be removed first. This panel is equipped with
a door switch, which shuts the unit down when it is
removed. The filter rack must be removed next.
WIRING – LOW VOLTAGE WIRING
230/208V, 1 Phase and 3 Phase Equipment Dual
Primary Voltage Transformers
All equipment leaves the factory wired on 240V tap.
For 208V operation, reconnect from 240V to 208V tap.
The acceptable operating voltage range for the 240 and
208V taps are as noted in Table 2.
The standard Climate Control
Option X
is a remote
thermostat connection terminal block. See Figure 14
for wiring diagram. Compatible thermostats are listed
in Table 3.
The Climate Control
Option D
is an electronic,
programmable thermostat. The subbase of the
thermostat is factory wired to the front panel of the
unit. See Figure 15 for wiring diagram. Compatible for
use with Energy Recovery Ventilator or Economizer.
The Climate Control
Option H
is an electronic,
programmable thermostat and CO
2
controller. The
subbase of the thermostat and CO
2
controller are
factory wired to the front panel of the unit. See Figure
16 for wiring diagram.
GENERAL
This unit is equipped with a variable speed ECM motor.
The motor is designed to maintain rated airflow up to
the maximum static allowed.
It is important that the
blower motor plugs are not plugged in or unplugged
while the power is on. Failure to remove power prior
to unplugging or plugging in the motor could result in
motor failure.
NOTE: The voltage should be measured at the field
power connection point in the unit and while
the unit is operating at full load (maximum
amperage operating condition).
TABLE 2
Operating Voltage Range
TABLE 3
Wall Thermostat
CAUTION
Do not plug in or unplug blower motor
connectors while the power is on. Failure to
do so may result in motor failure.
TAP
RANGE
240V
253 - 216
208V
220 - 187
Thermostat
Predominant Features
8403-060
(1120-445)
3 stage Cool; 3 stage Heat
Programmable/Non-Programmable
Electronic
HP or Conventional
Auto or Manual changeover
8403-081
(VT8650U5500B)
2 stage Cool; 2 stage Heat
Programmable/Non-Programmable
Electronic
HP or Conventional, Auto or Manual
changeover with Humidity and
Occupancy Sensor, BACnet
