Bard Q24H3-A Installation Instructions Manual Download Page 19

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Manual 2100-652A
Page

19 of 42

OPTIONAL CLIMATE CONTROLS

SEQUENCE OF OPERATION

The standard Climate Control

Option X

is a remote

thermostat connection terminal block. See Figure 17A
on page 22 for wiring diagram. Compatible thermostats
are listed in Table 4 on page 21. See Figure 17B on
page 23 for Remote CO

Sensor Connection.

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 18 on page 24 for wiring diagram. It
is compatible for use with Energy Recovery Ventilator
or Economizer. The thermostat can be set in the
heat, cool or automatic mode. When the thermostat
is set in the heat mode, it can heat only to maintain
the temperature set on the thermostat. When the
thermostat is set in the cool mode, it can cool only
to maintain the temperature set on the thermostat.
When the thermostat is set in the automatic mode,
the thermostat can change automatically to the heat
or cool modes to maintain the temperature set on the
thermostat.

Climate Control

Option H

is an electronic,

programmable thermostat and a CO

controller. The

subbase of the thermostat and CO

controller are

factory wired to the front panel of the unit. See Figure
19 on page 25 for wiring diagram. The thermostat can
be set in the heat, cool or automatic mode. When the
thermostat is set in the heat mode, it can heat only to
maintain the temperature set on the thermostat. When
the thermostat is set in the cool mode, it can cool only
to maintain the temperature set on the thermostat.

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

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.

TABLE 3 – Operating Voltage Range

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).

The field wiring connections are located behind the
top and hinged panel in the circuit breaker panel (see
Figure 15).

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 3.

TAP

RANGE

240V

253 – 216

208V

220 – 187

FIGURE 15

Component Location

Dehumidification

Control (Optional)

Unit

Mounted