Wiring - Low Voltage; Low Voltage (24Vac) Connections; Unit Shutdown Feature; Balanced Climate Tm Feature - Bard W42AC-A Installation Instructions Manual

Wiring – Low Voltage
All 230/208V 1 phase and 3 phase equipment have
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:
Tap: 240 Range: 253 – 216
Tap: 208 Range: 220 – 187
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).
For low voltage wiring, an 18 gauge copper, color-coded
cable is recommended. See Table 8 on page 20 for
more information.

Low Voltage (24VAC) Connections

These units use a 24-volt AC low voltage circuit.
C terminal is the 24VAC common and is grounded.
G terminal is the indoor blower input.
Y1 terminal is the 1st Stage input for cooling.
Y2 terminal is the 2nd Stage compressor input for cooling
(if equipped with an economizer) or Y2 disables Balanced
Climate mode if the Y1-Y2 jumper is removed (see page
18).
B/W1 terminal is the 1st stage electric heat.
W2 terminal is the 2nd stage heat (if equipped).
A terminal is the ventilation input. This terminal
energizes any factory-installed ventilation option and
indoor blower.
D terminal is the dehumidification input. If installed, this
terminal energizes any factory-installed dehumidification
option.
L terminal is 24 volt alarm active output.
For units equipped with an alarm relay:
1 terminal is the normally closed contact on the relay.
2 terminal is the normally open contact on the relay.
3 terminal is the common contact on the relay.
See Table 3 for additional low voltage connections.
Manual 2100-692
Page 18 of 40
TABLE 3
Additional Low Voltage Connections (if applicable)
Terminal Unit
V Control
9
Option Only
V Control
10
Option Only
F, V Control
11
Options
F, V Control
12
Options
V Control
13
Option Only
V Control
14
Option Only
V Control
15
Option Only
V Control
16
Option Only
Unit Shutdown Feature (Standard on All Models)
The RT terminal is the 24VAC transformer output,
and the R terminal is the 24VAC hot terminal for the
operation of the equipment. RT and R are connected
with a brass jumper bar which can be removed and RT
and R connected to an external NC (normally closed)
contact such as a fire/smoke detector that will cause
shutdown of the equipment upon activation.
Balanced Climate™ Feature (Standard on All Models)
All units are equipped with the capability of running
in Balanced Climate mode. This mode is designed to
enhance the comfort level by reducing the indoor airflow
amount and extending the run time to help extract more
humidity during cooling operation. The Y1 terminal
is the 24VAC input for Balanced Climate compressor
cooling operation. The Y2 terminal is the 24VAC input
for compressor cooling standard operation. Y1 and Y2
are connected with a brass jumper bar which can be
removed to enable Balanced Climate mode. Units with
an economizer will not have the brass jumper installed.
Refer to vent manuals for instructions on how Balanced
Climate works with each vent.
To operate in Balanced Climate mode, a 2-stage
cooling thermostat is required. The lower indoor airflow
operation is overridden by utilizing a 2-stage thermostat.
If the call for cooling is not satisfied within a given
time frame or temperature differential (specified by
the thermostat), the thermostat will send a signal to
Y2 which then increases the blower speed back to the
selected speed. See pages 33 – 35 for blower speed
selection options.
Refer to page 24 for additional Balanced Climate
requirements and limitations.
Description
Discharge Air Sensor,
10K Ohm
Discharge Air Sensor,
10K Ohm
Filter Switch,
Normally Open Contact
Filter Switch,
Normally Open Contact
Blower Airflow Switch,
Normally Open Contact
Blower Airflow Switch,
Normally Open Contact
Compressor Current Sensor,
Normally Open Contact
Compressor Current Sensor,
Normally Open Contact