Control Provided - Honeywell CVL4022ASVAV1 Engineering Manual

Control Provided

The CVL Controllers are primarily intended for pressure
independent, single duct VAV box control. Pressure
independent control specifies that the individual zone terminal
unit has a means for maintaining a consistent volume of air
into the zone regardless of the input static pressure. The
controller modulates the air flow into the zone to satisfy the
Zone Temperature Setpoint. Minimum Air Flows are
maintained except during emergency strategy periods or
during building Unoccupied periods if using physical position
stops, a MIN/MAX air flow is always maintained (see Table 3).
Mode
Effective Occupancy
OCCUPIED Controller is in Occupied mode
STANDBY Controller is in Standby mode.
UNOCCUPIED Controller is in Unoccupied mode.
Override Modes
OCCUPIED Controller is in Occupied mode.
UNOCCUPIED Controller is in Unoccupied mode.
BYPASS User-initiated Bypass of the
Unoccupied mode
NOT ASSIGNED No Bypass action.
Operational Modes
START-UP AND Configurable flow Diversity on
WAIT (followed by) power-up provides a staggered start
sequence to evenly apply the load to
the supply fan and electrical system.
COOLING The VAV Controller is controlling the
Cooling mode.
HEATING The VAV Controller is controlling the
Heating mode.
REHEAT The VAV Controller is controlling the
Reheating mode.
MORNING The main AHU is supplying warm air
WARMUP and the box damper is set at
(WarmupDmprPos)
NIGHT PURGE The main AHU is supplying fresh
(100 percent outdoor) air, and box
damper is set at (PurgeDmprPos)
Table 3. Modes of Operation For CVL Controller
Description
Any of the following: Local schedule state, Network input
(nviTodEvent) containing time- of-day schedule, flag from either an
Occupancy Sensor Digital Input, or from the Network input
(nviManOcc) for manual override to OCCUPIED mode.
Local schedule, Network input (nviTodEvent) containing time-of-day
schedule flag from the network must be OCCUPIED and the
Occupancy Sensor Digital Input must be UNOCCUPIED.
Local schedule, Network input (nviTodEvent) containing time-of-day
schedule flag from either an Occupancy Sensor Digital Input, or
from the Network input (nviManOcc) has a value of UNOCCUPIED.
Network input (nviTodEvent) containing time-of-day schedule flag
from the Network input (nviManOcc) for manual override to
OCCUPIED mode.
Network input (nviTodEvent) containing time-of-day schedule flag
from the network input (nviManOcc) has a value of UNOCCUPIED.
Digital input (wall module override push button) has been pressed
or override initiated from Zio and the Bypass duration timer has not
yet expired, or the network input nviBypass received.
No Override input received.
These modes occur on controller power-up, and after downloading
to the controller from the tool or going to auto mode to manual
mode. Temperature and flow control loops are disabled.
Network input nviApplicMode containing AHU operational mode
information from other LONWORKS Bus controllers that have the
value of COOL/AUTO.
Network input nviApplicMode containing AHU operational mode
information from other LONWORKS Bus controllers that have the
value of HEAT/AUTO. Unit switches to Heat mode when warm air is
supplied to the terminal unit.
Network input nviApplicMode has the value of AUTO, so that when
cool air is supplied to the box and the space temperature is below
the Heating Setpoint, causes the control algorithm to energize the
Reheat coil(s).
Network input nviApplicMode containing AHU operational mode
information from LONWORKS Bus controllers that have the value
of MORINING WARM-UP.
Network input (nviApplicMode) containing AHU operational mode
information from LONWORKS Bus controllers that have the value
of NIGHT PURGE.
Pressure dependent control specifies that the damper position
is controlled by space temperature only and not by a
measurement of air flow volume. The amount of air delivered
to the zone at any given damper position is dependent on the
static pressure in the supply air duct (physical position stops,
range stop pins, are used to keep the damper at a fixed
position). Additional outputs are available for control of heating
systems such as reheat coils for Heat mode or Morning warm-
up mode operation. The heating equipment can be staged-
resistive heating, staged 2-position (solenoid) valve, or
modulated steam or hot water valve.
.
Events Causing a Controller to Switch to This Mode
5 31-00083—02