Timed Override Activation-Ics; Ics; Vav Drive Max Output; Occupied Sequence - Trane Technologies IntelliPak Signature SCWF Installation, Operation And Maintenance Manual

Timed Override Activation—ICS™
This function is operational whenever the unit's RTM
module is used as the zone temperature sensor source,
which can be set at the HI panel. When this function is
initiated by the push of the override button on the zone
sensor, the unit will switch to the occupied mode. Unit
operation (occupied mode) during timed override is
terminated by a signal from Tracer.
Timed Override Activation—Non-ICS
This function is active whenever the unit's RTM module
board is selected as the zone temperature source, which
can be set at the human interface panel. When this function
is initiated by the push of the override button on the zone
sensor, the unit will switch to the occupied mode.
Automatic cancellation of the timed override mode occurs
after three hours of operation.

VAV Drive Max Output

This is a single-pole, double-throw relay rated at a
maximum voltage of 24 vac, two amps max. The relay
contacts of this relay switch when the unit goes from the
occupied mode to the unoccupied mode by means of the
unoccupied binary input, night setback zone sensor, or
Tracer Summit. The contacts will stay switched during the
unoccupied and morning warm-up mode. They will return
to the position shown on the unit wiring diagram when the
unit returns to the occupied mode. The intent of this binary
output is to signal the VAV boxes or other terminal devices
to go to a full open airflow position.

Occupied Sequence

All setpoints can be adjusted using the HI panel. Also,
cooling/heating setpoints can be adjusted in the zone, if
using an adjustable zone sensor. For a complete list of unit
setpoint default values and ranges, see the IntelliPak™
Self-Contained Programming Guide, PKG-SVP01*-EN.
Occupied Zone Temperature—Cooling
The unit transitions from unoccupied to occupied when the
occupied/unoccupied input on the RTM is open for more
than five seconds after having been closed. This input can
be received from Tracer Summit, the remote NSB zone
sensor, the timed override function, or a field supplied
contact. Dependent on unit options and the HI
programming, the following sequence will occur:
• The unit will begin MWU and then switch to the
occupied mode after the MWU setpoint is met.
• Purge will be enabled by Tracer Summit. Then Tracer
Summit will enable the occupied mode.
• The unit will switch from unoccupied to occupied
control immediately.
Upon entering occupied mode, the occupied/unoccupied
relay will de-energize.
SCXF-SVX01T-EN
Zone Temperature Control (Unit Model
Number Digit 9 = 4 or 5)
A zone sensor located directly in the space sends input to
the RTM while the CV unit is in occupied cooling mode.
When the unit is in occupied cooling, the RTM controls the
zone temperature within the cooling setpoint deadband by
modulating the economizer option and/or staging
mechanical cooling on and off as required.
Supply Air Temperature Control (Unit
Model Number Digit 9 = 1, 2, 3, or 6)
When the VAV unit is in occupied cooling, the RTM controls
the supply air temperature to the specified supply air
cooling setpoint by modulating the economizer option and/
or staging mechanical cooling on and off as required. The
changeover relay contacts (field supplied) must be open on
units with hydronic heat for cooling to operate.

Cooling

Upon entering occupied mode, the RTM receives an input
from either the HI, RHI, Tracer Summit, or the GBAS to
start the supply fan. The RTM supply fan contacts close
and energize the supply fan contactor. When the supply fan
starts, the fan proving switch closes, signaling the RTM that
airflow is established. The VFD will ramp the fan, and/or
the airside economizer dampers will open to the user-
defined minimum position.
When a cooling request is sent to the RTM from the zone
sensor, the RTM evaluates the system operating conditions
using the supply air and outdoor temperature input before
sending the request to the MCM for mechanical cooling. If
outdoor conditions (temperature and humidity) are suitable
or the EWT is within specified setpoints, the RTM will
attempt to use "free cooling" without using any
compressors. The RTM will use either the airside or
waterside economizer option. When outdoor air conditions
are not suitable, only mechanical cooling will function and
outside air dampers will remain at their minimum position. If
the unit does not have an economizer, mechanical cooling
will operate to satisfy cooling requirements.

Units With Economizer

If the entering condenser water temperature (units with a
WSE) or the outside air enthalpy (units with an ASE) is
appropriate to use "free cooling," the economizer will
attempt to satisfy the cooling zone temperature setpoint.
Note: When using an ASE with economizer enabled, O/A
temperature enable can be used instead of
comparative enthalpy if the O/A temperature falls
below the economizer setpoint.
Then compressors will stage on as necessary to maintain
supply air temperature setpoint, which is user-defined at
the HI. Minimum on/off timing of compressors prevents
rapid cycling.
When both airside and waterside economizers are on a
single unit, priority must be set at the HI. The economizer
Operating Principles
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