Constant Volume Or Variable Air Volume Applications - Trane Voyager Commercial Installation & Operation Manual

Supply Air Temperature Reset
The supply air temperature can be reset by using one of four DIP switch configurations on the RTAM
or through ICS when a valid supply air reset setpoint with a supply air reset amount is given. A
selectable reset amount of 0° F to 20° F via RTAM potentiometer or ICS is permissible for each type
of reset.
The amount of change applied to the supply air temperature setpoint depends on how far the return
air, zone, or outdoor air temperature falls below the reset temperature setpoint. If the return air,
zone, or outdoor air temperature is equal to or greater than the reset temperature setpoint, the
amount of change is zero.
If the return air, or zone temperature falls 3° F below the reset temperature setpoint, the amount
of reset applied to the supply air temperature will equal the maximum amount of reset selected.
If the outdoor air temperature falls 20° F below the reset temperature setpoint, the amount of reset
applied to the supply air temperature will equal the maximum amount of reset selected. The four
DIP switch configurations are as follows:
1. None - When RTAM DIP Switch #3 and #4 are in the "Off" position, no reset will be allowed.
2. Reset based on Return Air Temperature - When RTAM DIP Switch #3 is "Off" and Switch #4 is
3. Reset based on Zone Temperature - When RTAM DIP Switch #3 is "On" and Switch #4 is "Off",
4. Reset based on Outdoor Air Temperature - When DIP Switch #3 and #4 are "On", a selectable

Constant Volume or Variable Air Volume Applications

Off Mode
This mode is set at the zone sensor or by ICS. During this status, no heating, ventilation, or
mechanical cooling is being performed. When switching the "System" selector to the "Off" mode
from any other mode, any diagnostic data and diagnostic indication signal will be retained as long
as the system remains in the "Off" status. Switching the "System" selector from the "Off" mode back
to any other mode of operation will reset all diagnostics.
Zone Temperature - Unoccupied Cooling (CV Only)
While a building is in an unoccupied period as designated by a remote panel with night setback,
ICS or RTRM J6-11 and J6-12, the necessary stages of cooling will cycle to maintain the zone
temperature to within the unoccupied setpoint deadband. If an economizer is enabled, it will
modulate in an attempt to maintain the zone temperature to within the setpoint deadband.
Zone Temperature - Unoccupied Heating
While a building is in an unoccupied period as designated by a remote panel with night setback or
ICS, the necessary stages of heat will cycle to maintain the zone temperature to within the
unoccupied setpoint deadband. For VAV systems, the IGV's or VFD's will operate at 100% during
this mode. It will be necessary to drive VAV boxes to their maximum position through ICS
programming or the factory provided VHR relay.
Mechanical Cooling with an Economizer
The economizer is utilized to control the zone temperature providing the outside air conditions are
suitable. The method used to determine economizer effectiveness, depending on the available
data, is described below in descending order of complexity. The most sophisticated method
available is always used.
RT-SVX34C-EN
"On", a selectable supply air reset setpoint of 50° F to 90° F via a unit mounted potentiometer
or Tracer™ is permissible.
a selectable supply air reset setpoint of 50° F to 90° F via RTAM potentiometer or Tracer is
permissible.
supply air reset setpoint of 0° F to 100° F via RTAM potentiometer or Tracer is permissible.
Startup
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