AAON Orion VCCX2 User Manual

77
VCCX2 Controller Technical Guide
Primary and Secondary Heating
The VCCX2 can activate two forms of Heating, which are
classied as Primary and Secondary Heat Sources. The following
section describes that operation.
Primary Modulating Heat with Secondary Staged
Heat
The Modulating Heat source can be ModGas, Modulating Hot
Water, Modulating Steam, or SCR Electric Heat. In this case the
modulating heat will be the rst form of heat used and will operate
as described above to attempt to achieve the Active Supply Air
Heating Setpoint. If the modulating heat reaches 100%, the
Heating Stage Up Delay begins. If the Primary Heat Source
is still at 100% after the Heating Stage Up Delay expires, the
Secondary Heat Source will activate. The Primary Heat Source
can then modulate as necessary to achieve the Active Supply Air
Heating Setpoint. If there are additional stages of heat, they will
stage up as described, with the Primary Heat Source modulating
as necessary.
If the Secondary Heat Source is activated and the Primary Heat
Source has modulated to 0%, the Heating Stage Down Delay
will begin. If the Primary Heat Source is still at 0% after the
Heating Stage Down Delay expires, the Secondary Heat Source
will deactivate. If there are multiple stages of Secondary Heat,
they will stage o in the same manner. Then, if the Supply Air
Temperature rises above the Active Supply Air Heating Setpoint
plus the Heating Stage Control Window, the Primary Heat Source
will modulate to 0% to allow the Supply Air Temperature to
cool o.
Ventilation Mode
This mode is only available in the Occupied Mode of operation
on units congured for continuous Supply Fan operation and is
generated anytime there is no demand for heating or cooling.
The fan will operate at the congured Minimum Vent speed.
Off Mode
O Mode occurs in the Unoccupied Mode when there is no
heating or cooling demand. The Supply Fan is o and the outside
air damper is closed.
O Mode can only occur in the Occupied Mode if the fan is
congured to cycle with heating and cooling and there is no call
for heating or cooling.
Remote Contact Control
A Remote Contact Control option can be congured on the
VCCX2 Controller to initiate the HVAC Modes of operation.
If this option is configured, all Heating, Cooling, and
Dehumidication modes will only be initiated based on 24 VAC
wet contact closures on the Forced Heating, Forced Cooling, and
Forced Dehumidication inputs on the VCCX2 Controller. This
is a single conguration option that applies to all three modes.
If both the Forced Heating and Forced Cooling inputs are inactive
or if both are simultaneously active, then the unit is in a Vent
mode (neutral) state. In this condition in the Occupied Mode,
only the fan would be on for ventilation. In this condition in the
Unoccupied Mode, the unit would just be O.
If Forced Dehumidication is also being used, it will operate
in conjunction with the Forced Heating and Forced Cooling
inputs according to which Dehumidication option you have
congured. The four conguration options are described in the
Dehumidication Mode section on page 67.
Space Sensor Operation
Space Sensors are available as a Plain Sensor, Sensor with
Override, Sensor with Setpoint Slide Adjust, and Sensor with
Override and Setpoint Slide Adjust (this is the version that is
factory supplied).
An E-BUS Digital Space Sensor is also available with override
and setpoint adjustment capability.
Sensors with Setpoint Slide Adjust can be programmed to allow
Space Setpoint adjustment of up to ± 10° F.
If the Space Temperature is the SAT/Reset Source, then the Slide
Adjust will adjust the HVAC Mode Enable Setpoints and the
SAT/Reset Source Setpoints simultaneously.
During Unoccupied hours, the Override Button can be used to
force the unit back into the Occupied Mode (by pressing the
button for less than three seconds) for a user-dened override
duration of up to 8.0 hours. Pressing the button between three
to 10 seconds cancels the override.
SEQUENCE OF OPERATIONS
Ventilation Mode, Remote Contact Control, and Space Sensor Operation

AAON Orion VCCX2 Specifications

General

Brand	AAON
Model	Orion VCCX2
Category	Controller
Language	English