15
-
The damper position is never linear or proportional to airflow in a pressure dependent application.
Depending on how the zone damper was sized, a box may best slightly oversized, or slightly
undersized. In all cases, the PI loop (Proportional Integral) of the zone thermostat will always
compensate to find the proper required position to satisfy the current zone demand.
-
Be sure the VAV actuator is properly installed and set-up so the VAV damper blade is able to
rotate from the fully opened, to fully closed position with no restriction to its mechanical rotation.
2F) Terminal Reheat Lockout
It is possible to lockout out the local terminal reheat function of the zones during hot seasons or when no
longer required. This prevents users from using the local reheat function simply based on a configured
outside air temperature value.
If RehtConf is set to
AO2 OALK
BO5 OALK
0 = None
N/A, reheat not used
N/A, reheat not used
1 = Analog Duct Reheat Only
Set to desired value
N/A BO5 not used by this reheat
sequence
2 = On/Off Duct Reheat Only
N/A AO2 not used by this reheat
sequence
Set to desired value
3 = On/Off Perimeter Reheat Only N/A AO2 not used by this reheat
sequence
Set to desired value
4 = Analog Duct Reheat & On/Off
Perimeter Reheat
Set to desired value. Can be
different than BO5 OALK
Set to desired value. Can be
different than AO2 OALK
2G) Passive Infra Red Motion Detector Cover (PIR)
The Viconics zone thermostats are compatible with the new Viconics PIR (Passive Infra Red) cover
accessory. Thermostats equipped with a PIR cover provide advanced active occupancy logic, which can
automatically switch occupancy levels from occupied to stand-by as required when local activity is detected
in the room.
This advanced occupancy functionality provides advantageous energy savings during occupied hours
without sacrificing occupant comfort. All zone thermostats can be ordered with or without a factory installed
PIR cover.
This allows zones, which are infrequently occupied such as a conference room, storage areas or other
rooms to use relaxed set points during periods when there are no occupants present in the zone.
The advantage of using stand-by set points is to permit the system to recover fairly rapidly from stand-by to
occupied set points once movements are detected in a zone. The relaxed values of the stand-by setpoints
need to be far enough from occupied set points to optimise the energy savings a PIR cover can provide yet
close enough for the system to recover quickly and be within the occupants comfort zone in as short a time
as possible. If the span (Delta Temperature) from occupied to stand-by setpoints is too large, the zone will
not be able to recover quickly and the occupants will be left uncomfortable for the duration of the occupied
periods initiated by the PIR.
% opening
Air flow
% opening
Air flow
Oversized VAV
Undersized VAV
Effective
Control
Area
Effective
Control
Area
