Sequence of operations, Operation modes – Orion System PREHEAT-X User Manual
Page 10
Zone
Zone
SEQUENCE OF OPERATIONS
10
PREHEAT-X Technical Guide
Preheat Enable
Stand Alone Mode
Enabled when the Binary Input is closed and the Entering Air Tem-
perature is below setpoint.
E-BUS Communications Mode
Enabled by an E-BUS command when the Entering Air Temperature
falls below the Preheat Setpoint.
BACnet Communications Mode
Enabled by BACnet command or Binary Input, whichever occurs
fi rst.
Leaving Air Sensor
The controller can be confi gured to use one of three sensor confi gu-
rations for control.
•
Leaving Air Sensor 1 only (LAT1)
•
Leaving Air Sensor 2 only (LAT2)
•
Average Leaving Air Temperature which averages
LAT1 and LAT2
Leaving Air Setpoint
Stand Alone
•
Leaving Air Temperature Setpoint can be reset
between the LAT Setpoint and LAT Setpoint Reset
Limit.
•
The Reset Source is based on a 0-10 VDC input and
range can be adjusted using the LAT Setpoint Reset
Source Low and LAT Setpoint Reset Source High
Setpoints.
E-BUS and BACnet Communications Mode
•
A Leaving Air Temperature Setpoint will be sent to
the
controller.
•
This value is stored in volatile memory and will be
lost at reset.
•
There are separate Leaving Air Temperature Setpoints,
depending on if the unit is in Heating, Vent, or Cool
Mode.
Modulating Heat
• If
confi gured, the Modulating Heat output will be used
as
the
fi rst stage of heat.
•
Analog Voltage Output can be adjusted between
0-10 VDC as needed to maintain the Leaving Air
Setpoint.
•
Controlled by an Internal PID Loop.
Heat Staging Up
The following conditions must be met before the fi rst (next) stage
of heat can be energized:
•
Preheat Enable Signal/Command must be active.
•
The LAT must be below the LAT Setpoint by any
amount.
•
If Mod Heat is confi gured, it must be at 100% for the
Stage Up Delay.
•
The Minimum Off Time must be met.
•
The Stage Up Delay must be met (for second stage
and
above).
Heat Staging Down
The following conditions must be met before a stage of heat can be
de-energized:
•
Preheat Enable Signal/Command is deactivated
-OR- the LAT must be above the LAT Setpoint by the
LAT
Deadband.
•
If Modulating Heat is confi gured, it must be at 0% for
the stage down delay.
•
The Minimum Run time must be met.
•
The Stage Down Time must be met.
Operation Modes