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The Holiday schedule is created to override the Daily
schedule and identify a specific day and month of the year
to start and stop the unit and cha nge control to the
unoccupi ed heating and cooling setpoints. Follow t he
same steps to turn on one of the twelve Holiday schedules
and start and stop times. Next, select one out of the twelve
months and one out of the thirty--one days of that month.
The RTU--MP will now ignore the Daily schedule for the
specific day and time you selected and follow the Holiday
Schedule for thi s period.
The Override schedules primary purpose is to provide a
temporary change in the occ upied heating and cooling
setpoints and force the unit to control to the unoccupied
heat ing and cooling setpoints. This would occur on a set
day in a particular month and last during the start and stop
time configured. The Override schedule is enabled by
following the same steps to create the Holiday schedule.
NOTE: Push button override is only available when
running a local or BACnet Schedule.
BACnet Schedule
For use with a Building Automation System that supports
native BACnet scheduling is scheduling the unit. With the
Occupancy Source set to BACnet schedule the BAS will
control the unit through network communication and it’s
own scheduling function.
BAS On/Off
The Building Automation System is scheduling the unit
via an On/Off command to the BAS ON/OFF software
point. The Building Automation System can be speaking
BACnet, Modbus, or N2 and is writing to the BAS On/Off
point i n the open protocol point map.
NOTE: If the BAS supports NATIVE BACnet
scheduling, then set the Occupancy Source to BACnet
schedule . If the BAS is BACnet but does NOT support
NATIVE BACnet sche duling, then set the Occupancy
Source to BAS On/Off.
DI On/Off
A hard--wired input on the RTU--MP will command the
unit to start/stop. Inputs 3, 5, 8, and 9 on plug J5 can be
hard--wired to command the unit to start/stop.
NOTE: Scheduling can either be controlled via the unit
or the BAS, but NOT both.
Indoor
Fan
The indoor fan will be turned on whenever any one of the
following conditions is true:
S It is in the occupied mode. This will be determined by its
own internal occupancy schedule .
S Whenever there is a demand for cooling or heating in the
unoccupi ed mode.
S Whenever the remote occupancy switch is closed during
DI On/Off schedule t ype or if occ upancy i s forc ed
occupi ed by the BAS during BAS On/Off schedule type.
When transitioning from unoccupie d to occupied, there
will be a configured time delay of 5 to 600 seconds before
starting the fan. The fan will continue to run as long as
compressors, heating stages, or the dehumidification
relays are on when transit ioning from occupied to
unoccupi ed with the exception of Shutdown mode. If Fire
Shutdown, safety chain, SAT alarm or SPT alarm are
active; the fan will be shutdown immediately regardless of
the occupancy state or de mand.
The RTU--MP has an optional Supply Fan Status input to
provide proof of airflow. If this is enabled, the point will
look for a contact closure whenever the Supply Fan Relay
is on. If it is not enabled then it will always be the same
state as the Supply Fan Relay. The cooling, e conomizer,
heat ing, dehumidification, CO
2
and power exhaust
routines wil l use t his input point for fan status.
Cooling
The compressor outputs are controlled by the Cooling
Control PID Loop and Cooling Stages Capacity algorithm.
They will be used to calculate the desired number of
stages needed to satisfy the space by comparing the Space
Temperature (SPT) to the Occupied Cool Setpoint plus the
T56 slider offset when occupied and the Unoccupied Cool
Setpoint (UCSP) plus the T56 slide r offset, if unoccupied.
The economizer, if ava ilable, will be used for cooling in
addition to the compressors. The following conditions
must be true in order f or this algorithm to run:
S Indoor Fan has been ON for at least 30 seconds.
S Heat mode is not active and the time guard between
modes equals zero.
S If occupied and the SPT >(occupied cool setpoint plus
the T56 slider offset).
S Space Temperature reading is available.
S If it is unoccupi ed and the SPT > (unoccupied cool
setpoint plus the T56 slider offset). The indoor fan will be
turned on by the staging algorithm.
S If economizer is available and active and economizer
open > 85% and SAT > (SAT low limit + 5_F) and SPT >
effective setpoint + 0.5_F.
OR
Economizer is available, but not active
OR
Economizer is not available
S OAT > DX Lockout temperature.
If all of the above conditions are met, the compressors
will be energized as required, otherwise they will be
de--energized.
There is a fixed 3--minute minimum on time and a
5--minute off time for each compressor output and a
3--minute minimum time delay between staging up or
down.
Any time the compressors are running the RTU-- MP will
stage down the compressors if the SAT becomes less than
the cooling low supply air setpoint.
After a compressor is staged off, it may be started again
after a normal time --guard period and the supply air
temperature has increased above the low supply air
setpoint.
48TC