Wiring - Main Power; Wiring - Low Voltage; Optional Climate Controls Sequence Of Operation; Figure 15 Component Location - Bard Q-TEC Q24H3DA Installation Instructions Manual

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.
See START UP section for information on three phase
scroll compressor start-ups.
FIGURE 15
Component Location
Electric
Heaters
Unit
Mounted
Thermostat
Location
Dehumidification
Control
The field wiring connections are located behind the
top and hinged panel in the circuit breaker panel (see
Figure 15).
WIRING – LOW VOLTAGE
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 3.
NOTE: The voltage should be measured at the field
OPTIONAL CLIMATE CONTROLS
SEQUENCE OF OPERATION
The standard climate control Option X is a remote
thermostat connection terminal block. See Figure
17 or Figure 18 for wiring diagram. Compatible
thermostats are listed in Table 4.
Climate control Option E is an electronic,
programmable thermostat with humidistat. The
subbase of the thermostat is factory wired to the front
panel of the unit. See Figure 19 for wiring diagram.
Compatible for use with energy recovery ventilator.
Side Field
Wire Entrance
This unit has a refrigerant reheat circuit that is
controlled by a 3 way valve.
Remote
When the humidity is above the setpoint of the
Thermostat
Terminal
humidistat, the compressor circuit and the 3 way valve
Block
are energized and the evaporator airflow is reduced.
Indoor
The 3 way valve directs hot discharge gas into a
Blower
separate desuperheating condenser circuit that reheats
the conditioned air before it is delivered to the room.
When the humidistat is satisfied, the system switches
back to normal air conditioning mode.
Circuit Breaker
If the thermostat calls for cooling during
Panel and
Controls
dehumidification mode, the call for cooling takes
precedence over the dehumidification and the unit will
Lower cool until the thermostat is satisfied. Once the call for
Control
cooling is satisfied, the unit may continue to dehumidify.
Panel
If the thermostat calls for heat when the unit is in
the dehumidification mode, the electric heaters will
energize and the evaporator airflow will return to the
heating airflow. When the thermostat is satisfied,
TABLE 3
Operating Voltage Range
TAP
240V 253 – 216
208V 220 – 197
power connection point in the unit and while
the unit is operating at full load (maximum
amperage operating condition).
RANGE
Manual 2100-653
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