Product data
Damper positions
The dampers provide for full-blade modulation from fully-
closed to fully-open. This is designated as position 0 to po-
sition 15. Because individual zone requirements differ from
one building to another, the system has been equipped to
provide minimum and maximum damper positions. Maxi-
mum damper position changes the fully-open damper po-
sition to a maximum damper position which can be less
than or equal to the maximum (which is 15). Minimum
damper position changes the fully-closed damper position
to a minimum damper position which can be more than or
equal to the minimum (which is 0).
The range of the maximum damper position is from 8 to
15, in increments of 1. The flexibility of the maximum
damper position allows airflow requirements through the
damper to be fine-tuned to best satisfy the space. When
space use changes, airflow can be readjusted to suit the re-
quirements of the new space configuration.
The range of the minimum damper position is from 0 to
7, in increments of 1. The adjustment capability allows fine-
tuning of airflow into the space. Minimum circulation levels
can be provided to ensure space comfort.
A ventilation damper position and a supplemental heat
damper position are alsoused. Referto theIndoor Air Qual-
ity and Supplemental Heat application sections for more
information.Refer to theRadiatedSound performance tables
for damper sound information.
Indoor air quality
The IAQ (indoor air quality) feature allows the Carrier Com-
fort system to interface with the economizer on the HVAC
equipment and maintain the quality of indoor air within
acceptable limits. An IAQ sensor (CO
2
) is used to monitor
the IAQ levels in the zone or the return air duct. The moni-
tor thermostat controls the system fan and economizer dur-
ing an IAQ mode.
The IAQ feature can be defined as system or local IAQ.
Local zone IAQ consists of a zone controller with an IAQ
sensor. When the IAQ alarm is tripped in local mode, only
the zone damper of the zone controller enters IAQ mode.
For local IAQ, the monitor thermostat scans the bus to
gather information and monitors the status of the zone con-
trollers. When a zone controller gives the monitor ther-
mostat a local IAQ alarm (zone controller with local IAQ
sensor), the monitor thermostat turns on the system fan (if
in occupied mode). If the IAQ economizer delay is satisfied
and a zone still has a local IAQ alarm, the monitor thermo-
stat checks the outdoor air against the humidity and tem-
perature lockouts. If the IAQ lockout functions are not
tripped, the economizer relay is energized to bring fresh air
into the zone. When the zone IAQ is satisfied or the reset
temperature isreached, the monitorthermostat will deener-
gize the economizer relay. The system fan will return to its
normal operating mode.
System IAQ consists of a VVTt system with a bypass
controller having an IAQ sensor or a monitor thermostat in
monitor-only mode having an IAQ sensor. A monitor ther-
mostat in VVT monitor applications has no free inputs for
an IAQ sensor. When an IAQ alarm is tripped on the by-
pass controller or monitor thermostat, all system elements
which are user-configured to join system IAQ will enter IAQ
mode.
For system IAQ, the monitor thermostat scans the bus to
gather information and monitors the status of the bypass
controller and zone controllers. When the bypass controller
or the monitor thermostat (in monitor only mode) has a
system IAQ alarm, the monitor thermostat starts IAQ sys-
temmode andenergizes thesystemfan (ifinoccupied mode).
The monitor thermostat sends all the zone controllers the
system IAQ alarm. The bypass control moves to control the
IAQ Pressure Set Point. The zone controllers look at their
system IAQ options to determine if they will participate in
system IAQ mode. Each device checks the reset tempera-
ture to determine if IAQ is acceptable for its zone. All zone
controllers in system IAQ mode will position their dampers
in the maximum damper position. If the IAQ economizer
delay is satisfied and a zone still has a local IAQ alarm, the
monitor thermostat checks the outdoor air against the hu-
midity and temperature lockouts. If the IAQ lockout func-
tions are not tripped, the economizer relay is energized to
bringfresh airintothe zone.The bypass controllerwill modu-
late its damper to keep auser-configuredamount ofair flow-
ing into the zone. When the system IAQ is satisfied or the
reset temperature is reached, the monitor thermostat will
deenergize the economizer relay. The system fan will re-
turn to its normal operating mode.
The following sections describe the IAQ functions and
options of the monitor thermostat, zone controller, and by-
pass controller.
Monitor thermostat — The monitor thermostat controls
the system fan and economizer during an IAQ mode. The
monitor thermostat has 8 configurable IAQ options that
allow the IAQ mode to be customized for each application.
The monitor thermostat can be configured to participate
in system IAQ mode or to operate its zone normally.
Themonitor thermostat canbe configuredto operatewith
orwithoutan IAQsensorconnectedtoits relaypack(monitor-
only mode).
The monitor thermostat can configure how long the in-
door fan will operate before the economizer relay is ener-
gized. With a Carrier integrated economizer, the outside air
damper will go to the minimum position when the indoor
fan is energized after an alarm. If the monitor thermostat
is still receiving an IAQ alarm after the economizer delay
has expired, themonitor thermostat will energize theecono-
mizer relay and drive the economizer to the fully-open
position.
The monitor thermostat has a temperature reset function
which will allow fresh air to be brought into a zone even if
the temperature set points are exceeded.When warm, fresh
outside air is brought into a cooled zone, or cool, fresh out-
side air is brought into a heated zone, the zone tempera-
ture may drop or rise above user-configured limits. The
temperature reset function allows the zone temperature to
rise over the cooling set point or drop under the heating set
point within a user-configured limit to allow the indoor air
quality time to improve.
The monitor thermostat has 3 lockout functions which
will keep the system from entering IAQ (energizing the
economizer relay). The system can lockout on high outdoor
humidity, low outdoor air temperature, and high outdoor
air temperature.
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