AAON Orion VCCX2 User Manual

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VCCX2 Controller Technical Guide
Internal Week Schedule
An Internal Week Schedule, which supports up to two start/stop
events per day and allows scheduling of up to 14 holiday periods
per year is available for determining Occupied and Unoccupied
Schedules. It also allows for daylight savings conguration.
Broadcast Schedule
Eight external broadcast schedules are available with use of the
GPC-XP Controller.
Unoccupied Operation
Uses Unoccupied Setback Oset Setpoints for heating and
cooling calls. If Unoccupied Setback Setpoints are left at the
default 30°F, no Unoccupied Setback operation will occur and
the unit will be o.
The Outdoor Air Damper will be closed except if the unit is in
unoccupied Economizer Free Cooling mode.
If there is no call for Heating or Cooling, the unit will be o.
HVAC Modes of Operation
There are eight possible HVAC Modes of Operation. They are
as follows:
• Cooling Mode
• Heating Mode
• Vent Mode
• Dehumidication Mode
• Purge Mode
• Heat Pump
• Warm-Up Mode / Cool-Down Mode
• O Mode
Cooling Mode
Occupied Cooling is enabled when the temperature at the Mode
Enable Sensor rises one deadband above the Cooling Setpoint.
Cooling is disabled when the Mode Enable temperature falls one
deadband below the Cooling Setpoint. The setpoint and deadband
are user-adjustable.
Unoccupied Cooling operation is enabled when the Space
Temperature rises above the Cooling Mode Enable Setpoint plus
the Unoccupied Cooling Oset.
Mechanical cooling is disabled if the Outdoor Air Temperature
(OAT) falls 1°F below the Cooling Lockout Setpoint and will
remain disabled until the OAT rises 1° above the Cooling Lockout
Setpoint.
If the OAT disables mechanical cooling while it is currently
operating, mechanical cooling will stage o as minimum run
times and stage down delays are satised.
If the economizer is enabled, it will function as the rst stage of
cooling (see Economizer section).
Cooling with the Refrigerant System Modules
(RSMs)
On units with digital or VFD compressors, the VCCX2 Controller
will utilize one or more Refrigerant System Modules (RSMs).
Units with only fixed staged compressors that are doing
dehumidication or that require head pressure control would
also utilize an RSM. Each RSM will control the compressors,
condensers, and EXVs (on Bitzer VFD compressor units) for
one or two refrigeration circuits. Up to four RSMs may be used
in controlling up to eight circuits.
The RSMD is used for digital compressor units, including heat
pumps. The RSMV is used for Bitzer VFD compressor units (non
heat pumps). The RSMV-HP is used for Bitzer VFD compressor
units that are heat pumps. The RSMVC-P is used for Copeland
VFD compressor units.
In the Cooling Mode, as the Supply Air Temperature (SAT)
rises above the Active Cooling SAT Setpoint (see the Supply Air
Temperature Reset section for explanation), the compressors will
stage on and modulate to maintain the Active Supply Air Cooling
Setpoint. Each RSM will independently control its compressors
to achieve the most ecient cooling control. Each stage must
meet its Minimum O Time (adj.) before it is allowed to energize.
Successive stages are subject to a Cooling Stage Up Delay (adj).
Cooling stages will continue to run until the SAT falls below
the Active Supply Air Temperature Setpoint minus the Cooling
Stage Control Window at which point the cooling will begin to
stage o. Each stage must meet its Minimum Run Time (adj.)
before it is allowed to stage o. Successive stages are subject to
a Cooling Stage Down Delay (adj.). See the appropriate RSM
Technical Guide for a more detailed sequence of operation.
Staged Cooling without the Refrigerant
System Modules (RSMs)
On units with fixed stage compressor that are not doing
dehumidication and that do not require head pressured control,
or on units with On/O Chilled Water, an RSM will not be used.
In the Cooling Mode, as the Supply Air Temperature (SAT) rises
above the Active Supply Air Cooling Setpoint (see Supply Air
Temperature Setpoint Reset section for explanation), cooling will
begin to stage on. Each stage must meet its Minimum O Time
(adj.) before it is allowed to energize, and successive stages are
subject to a Cooling Stage Up Delay (adj).
SEQUENCE OF OPERATIONS
HVAC Modes of Operation

AAON Orion VCCX2 Specifications

General

Brand	AAON
Model	Orion VCCX2
Category	Controller
Language	English