Bard 11EER WA W18AB-A, Руководство пользователя для приложения

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Manual 2100-689H
Page 17 of 42
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.
NOTE: Units with mechanical dehumidification
require an additional connection to be made
when enabling Balanced Climate. Refer to
dehumidification supplemental instructions for
this step.
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 32 – 34 for
blower speed selection options.
Refer to page 22 for additional Balanced Climate
requirements and limitations.
Dehumidification Feature (Optional)
The D terminal is the 24VAC input for dehumidification
operation on dehumidification hot gas reheat equipped
units. When 24VAC is applied to the D terminal, a
3-way valve solenoid is energized. The reheat coil
located behind the evaporator coil is then active to
reheat the supply air during cooling mode. This allows
humidity to be removed from the air entering the unit
without a large amount of sensible cooling capacity.
During dehumidification, the indoor blower speed is
reduced to help with the humidity removal. A humidity
sensing thermostat or humidistat is required to control
dehumidification operation.
Ventilation Features (Optional)
See ventilation instructions provided with unit for low
voltage wiring.
Low Ambient Control (LAC)
The low ambient control is a pressure switch that is
attached to the liquid line of the system and monitors
high side pressure. Operation of the LAC occurs as
outdoor temperatures drop below 60°F. On/Off and
modulating controls are used which operate based
on pressure changes caused by outdoor temperature
changes. On/Off LAC operation cycles the condenser
fan on/off to maintain desired liquid pressure while
modulating LAC operation is factory adjusted and slows
the condenser fan speed (rpm).
Outdoor Temperature Switch and Freeze Protection
Thermostat
An outdoor temperature switch and an evaporator
freeze protection thermostat is supplied with all units
that have a low ambient control. The outdoor switch
disables Balanced Climate mode (if enabled) when
the temperature drops below 50°F. This prevents
potential evaporator coil freeze up issues. For units
with mechanical dehumidification, this switch must
remain disconnected when Balanced Climate mode
is not being used. Refer to unit wiring diagram. The
freeze thermostat cuts out compressor operation if the
evaporator begins to freeze up.
Alarm Relay Feature (Controls Option)
The alarm relay provides a set of NO (normally open)
and NC (normally closed) pilot duty contacts that
operate when the compressor control module locks out
compressor operation because of a high or low system
refrigerant pressure event.
DDC Controls Feature (Controls Option)
The DDC controls option provides additional sensors
that can be used with a field-supplied advanced logic
controller. The DDC controls option contains the
following installed components:
Dirty Filter Switch Indicator (DFS)
The switch is adjustable and measures pressure drop
across the unit filter surface. When pressure drop is
higher than the switch setting, NO contacts are provided
to indicate the filter needs to be serviced. Refer to page
34 for instructions on making switch adjustments.
Discharge Air Sensor
The discharge air sensor provides a temperature reading
of the supply air leaving the unit. The sensor is a 10K
OHM @ 77°F measuring device. It is installed in the
supply airstream in the heater bracket.
Airflow Switch
The airflow switch measures the pressure differential
between the blower inlet and outlet. It is located directly
above the blower partition. Relay contacts (NO) are
TABLE 3
Additional Low Voltage Connections (if applicable)
Terminal Unit Description
9
V Control
Option Only
Discharge Air Sensor,
10K Ohm
10
V Control
Option Only
Discharge Air Sensor,
10K Ohm
11
F, V Control
Options
Filter Switch,
Normally Open Contact
12
F, V Control
Options
Filter Switch,
Normally Open Contact
13
V Control
Option Only
Blower Airflow Switch,
Normally Open Contact
14
V Control
Option Only
Blower Airflow Switch,
Normally Open Contact
15
V Control
Option Only
Compressor Current Sensor,
Normally Open Contact
16
V Control
Option Only
Compressor Current Sensor,
Normally Open Contact