Appendix A: VAV Zone Controller Points/Properties
Point Name/Description
Default/Range
External Actuator Enable
– Enable if the controller's analog output is used for an external
high-torque or slave actuator. Enabling this setting disables the output for Modulating Hot
Water or Combination reheat functions.
D:
R:
Disable
Disable/Enable
Heat Type
– The type of supplemental reheat that the zone controller will control. The heat
may be used with system heat, depending on the space temperature demand.
Options:
None
– no heat
Modulating
– ducted or baseboard modulating hot water
Two Position
– two position hot water
Staged EH
– ducted or baseboard electric heat
Combination
– combination baseboard modulating hot water and ducted staged electric
heat
CV Modulating
– constant volume modulating reheat used for single duct terminal
application with modulating hot water reheat (typically used in hospital applications)
SCR Electric
– modulating control for SCR-type electric heater
D:
R:
None
None
Modulating
Two Position
Staged EH
Combination
CV Modulating
SCR Electric
Ducted Heat
– Determines whether the zone is using ducted heat or baseboard. If
Heat
Type
is
Combination
, set this field to
Yes
for ducted heat.
D:
R:
Yes
No/Yes
CV Modulating PID
– This BACnet object calculates the amount of capacity required to
satisfy the current space temperature setpoint, when the terminal is heating and the
Heat
Type
is set to
CV Modulating
.
CAUTION
The default values should be changed only by a technician trained in PID Loop
algorithms.
D: Type = reverse
Update Interval = 0:15
P = 20 (40 metric)
I = 1.0 (2.0 metric)
D = 0
Bias = 0
Deadband = 0
VAV Heating
– Set to
Enable
to have the terminal modulate its airflow to meet a zone
heating demand when the air source mode is Heating or Warm-up. Always set to
Disable
for parallel fan terminals.
D:
R:
Disable
Disable/Enable
Number of Heat Stages
– The number heat stages when the
Heat Type
is
Staged EH
. Fan-
powered terminals are limited to no more than 2 stages.
D:
R:
Two stages
One stage
Two stages
Three stages
Valve Type
– Two Position hot water only - The hot water valve's position with no power
applied to the valve.
D:
R:
NC
NC/NO (normally
closed/normally open)
Optional Sensor Type
– The type of sensor used on the controller's
RH/CO2
input. This
setting determines the control channel input function.
Options:
RH Sensor –
Relative humidity for zone dehumidification
IAQ Sensor
– Indoor air quality for DCV control
D:
R:
None
None
RH Sensor
IAQ Sensor
RH Control
– Enables or disables zone dehumidification control if valid RH sensor values
are available.
D:
R:
Disable
Disable/Enable
DCV Control
– Demand control ventilation control.
D:
R:
Disable
Disable/Enable
Min Setpoint Separation
– Minimum separation that must be maintained between the
heating and cooling setpoints.
D:
R:
4∆°F (2.2∆°C)
2 to 10∆°F
(1.1 to 5.5∆°C)
62
VAV Zone Controllers