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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.
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
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
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
Manual
2100-689J
Page
17 of 42
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