Outdoor Airflow Monitoring; Optional Field Enabled Features Demand Control Co2 Ventilation; Exhaust Fan Tracking; Static Pressure Control For Exhaust Fan - Trane Horizon OADG Series Installation, Operation And Maintenance Manual

Outdoor Airflow Monitoring

Units with Outdoor Air Flow Local In Service and
Modulating Dampers installed will modulate the Outdoor
Air Damper Position Command the Outdoor Air Minimum
Flow Setpoint. Damper position is restricted between the
Outdoor Air Damper Minimum Position Setpoint and
Outdoor Air Damper Maximum Position Setpoint.
Optional Field Enabled Features
Demand Control CO2 Ventilation
Modulating dampers are required for CO2 control. The
unit will modulate the Outdoor Air Damper Position
Command to maintain Space CO2 Concentration Local to
Space Concentration Setpoint. The CO2 concentration can
also be communicated to Space CO2 Concentration BAS.
CO2 Concentration must be field provided and installed.

Exhaust Fan Tracking

To enable exhaust fan tracking to the supply fan speed, set
Exhaust Fan Tracking Offset Setpoint to In Service and
adjust to the desired value (%). Putting this point In Service
will override all other default speed control for the exhaust
fan.

Static Pressure Control for Exhaust Fan

To enable exhaust fan control for a static pressure
setpoint, set Return Duct/Space Pressure Local to In
Service. The default input for this reading is XM70.2.UI12,
but the point can be configured to any open input on the
controller. The unit will modulate the Exhaust Fan Speed
Output Command to the Return Duct/Space Pressure
Local.
If a setpoint less than 0.25" WC is desired. It's
recommended to use a transducer that has a range of -0.5"
WC to 0.5" WC.

Unoccupied Operation

To enable heating, cooling, and dehumidification during
unoccupied operation, the BV Allow Unoccupied
Operation must be set as Allowed. Space conditions must
be communicated via BAS or a hardwire space/
temperature humidity sensor.

Starting Sequence

Unoccupied starting sequence begins when the
Unoccupied Heating, Cooling, or Dehumidification Mode
is enabled. Otherwise, the unit shall remain dormant with
the supply fan disabled. Supply Fan Startup sequence is
identical to occupied operation.

With Return Air Damper Installed

The outdoor air damper will be commanded to close, and
the return air damper will open. If the unit is under
Economizer conditions as described under the occupied
OAU-SVX006E-EN
section the Outdoor Air Damper Position Command will
open to the Outdoor Air Damper Maximum Position
Setpoint.

No Return Air Damper Installed

Identical to occupied starting sequence.

Unoccupied Heating Mode

Unoccupied Heating Mode is enabled when the Space
Temperature Active falls below the Unoccupied Heating
Enable Setpoint. During Unoccupied Heating Mode the
unit will run the heat to maintain 90°F for the discharge air
temperature. Unoccupied Heating Mode is disabled when
the Space Temperature Active rises 2°F above the
Unoccupied Heating Setpoint.

Unoccupied Dehumid Mode

When there is no call for Unoccupied Heating Mode,
Unoccupied Dehumid Mode is enabled when the Space
Dewpoint rises above the Unoccupied Dewpoint Enable
Setpoint. During Unoccupied Dehumid Mode the unit will
run the cooling to maintain 45°F for the evaporator leaving
temperature and reheat to 50°F for the discharge air
temperature. Unoccupied Dehumid Mode is disabled
when the Space Dewpoint rises 2°F above the Unoccupied
Dewpoint Enable Setpoint.

Unoccupied Cooling Mode

When there is no call for Unoccupied Heating Mode or
Unoccupied Dehumid Mode, Unoccupied Cooling Mode is
enabled when the Space Temperature Active rises above
the Unoccupied Cooling Enable Setpoint. During
Unoccupied Cooling Mode the unit will run the cooling to
maintain 50°F for the discharge air temperature.
Unoccupied Cooling Mode is disabled when the Space
Temperature Active rises 2°F above the Unoccupied
Cooling Enable Setpoint.

Diagnostics

The following list contains the diagnostics indicated by
Binary Values or Binary Inputs. These are typically
determined in the background of the program, and the
status is written to these points.
Analog Inputs, Analog Values, or other points may also
show alarms, which typically indicates that they are
outside of the normal range or that communication to the
device has been lost.
Energy Wheel with Optional Rotation Sensor
Units equipped with an optional rotation sensor detects
rotation status using a proximity sensor that detects
movement of the "pie" sections. If Energy Recovery Wheel
Start Stop Command is enabled, but the Energy Recovery
Wheel Rotation Status Local remains Off for five minutes,
Diagnostic: Energy Recovery Wheel Rotation Failure will
be displayed. This diagnostic is auto reset when rotation
status is detected.
Sequence of Operation
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