Sequence of Operation
OAU-SVX006E-EN
85
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
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.
