Carrier 50TCA04-A07 - Manual (Page 44)

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Heating may also be energized when an IAQ sensor
installed and has overridden the minimum economizer
damper position. If the OAT < 55_F and an IAQ sensor is
installed and the IAQ minimum position > minimum
damper position causing the SAT to decrease below the
SPT -- 10_F, then the heat stages will be cycled to temper
the SAT to maintain a temperature between the SPT and
the SPT + 10_F.
Auxiliary Relay configured for Exhaust Fan — If the
Auxiliary Relay is configured for exhaust fan (AUXOUT
= 1) in the CONFIG configuration table and Continuous
Power Exhaust (MODPE) is enable in the SERVICE
configuration table then the output (HS3) will be
energized whenever the G input is on. If the MODPE is
disabled then output will be energized based on the Power
Exhaust Setpoint (PES) in the SETPOINT table.
Indoor Air Quality — If the optional indoor air quality
(IAQI) sensor is installed, the PremierLink controller will
maintain indoor air quality within the space at the
user--configured differential setpoint (IAQD) in the
CONFIG configuration table. The setpoint is the
difference between the IAQI and an optional outdoor air
quality sensor (OAQ). If the OAQ is not present then a
fixed value of 400 ppm is used. The actual space IAQ
setpoint (IAQS) is calculated as follows:
IAQS = IAQD + OAQ (OAQ = 400 ppm if not present)
As air quality within the space changes, the minimum
position of the economizer damper will be changed also
thus allowing more or less outdoor air into the space
depending on the relationship of the IAQI to the IAQS.
The IAQ algorithm runs every 30 seconds and calculates
IAQ minimum position value using a PID loop on the
IAQI deviation from the IAQS. The IAQ minimum
position is then compared against the user configured
minimum position (MDP) and the greatest value becomes
the final minimum damper position (IQMP). If the
calculated IAQ Minimum Position is greater than the IAQ
maximum damper position (IAQMAXP) decision in the
SERVICE configuration table, then it will be clamped to
IAQMAXP value.
If IAQ is configured for low priority, the positioning of
the economizer damper can be overridden by comfort
requirements. If the SAT < SASP --8_F and both stages of
heat are on for more then 4 minutes or the SAT > SASP +
5_F and both stages of cooling on for more then 4 minutes
then the IAQ minimum damper position will become 0
and the IQMP = MDP. IAQ mode will resume when the
SAT > SASP --8_F in heating or the SAT < SASP + 5_F in
cooling. If the Premier--
Link controller is configured for 1 stage of heat and cool
or is only using a single stage thermostat input, this
function will not work as it requires the both Y1 and Y2
or W1 and W2 inputs to be active. In this application, it is
recommended that the user configure IAQ priority for
high.
If IAQ is configured for high priority and the OAT < 55_F
and the SAT < (SPT --10_F), the algorithm will enable the
heat stages to maintain the SAT between the SPT and the
SPT + 10_F.
CCN SENSOR MODE — When the PremierLink
controller is configured for CCN control, it will control
the compressor, economizer and heating outputs based its
own space temperature input and setpoints or those
received from Linkage. An optional CO2 IAQ sensor
mounted in the space or received through communications
can also influence the economizer and heating outputs.
The PremierLink controller does not have a hardware
clock so it must have another device on the CCN
communication bus broadcasting time. The controller will
maintain its own time once it has received time as long as
it has power and will send a request for time once a
minute until it receives time when it has lost power and
power is restored. The controller will control to
unoccupied setpoints until it has received a valid time.
The controller must have valid time in order to perform
any broadcast function, follow an occupancy schedule,
perform IAQ pre--occupancy purge and many other
functions as well. The following sections describe the
operation for the functions of the PremierLink controller.
Indoor Fan — The indoor fan will be turned on whenever
any one of the following conditions are met:
S If the PremierLink controller is in the occupied mode and
ASHRAE 90.1 Supply Fan is configured for Yes in the
CONFIG table. This will be determined by its own
internal occupancy schedule if it is programmed to
follow its local schedule or broadcast its local schedule as
a global schedule, or following a global schedule
broadcast by another device.
S If PremierLink controller is in the occupied mode and
ASHRAE 90.1 Supply Fan is configured for No and there
is a heat or cool demand (fan auto mode)
S If the PremierLink controller is in the occupied mode and
ASHRAE 90.1 Supply Fan is configured for Yes when
Linkage is active and the Linkage Coordinator device is
sending an occupied mode flag
S When Temperature Compensated Start is active
S When Free Cool is active
S When Pre--Occupancy Purge is active
S Whenever there is a demand for cooling or heating in the
unoccupied mode
S Whenever the Remote Contact input is configured for
Remote Contact (RC_DC=1 in SERVICE table) and it is
closed or the point is forced Closed via communications
in the STATUS01 points display table (remote contact
closed = occupied, remote contact open = unoccupied)
S Whenever the H3_EX_RV point is configured for
Dehumidification (AUXOUT=5 in CONFIG table) and it
is in the unoccupied mode and the indoor RH exceeds the
unoccupied humidity setpoint
50TC