58
RT-SVX34R-EN
If an Occupied “Heating” Mode is selected, the unit will
only function within the DWU perimeters until the
system is switched from the “Heat” Mode or enters an
Unoccupied status.
NNoottee:: When a LCI is installed on a VAV unit, the MWU
setpoint located on the RTAM board is ignored.
The MWU and DWU setpoints come from the
higher priority LCI-R DAC.
Supply Duct Static Pressure Control
The supply duct static pressure is measured by a
transducer with a 0.25 to 2.125 Vdc proportional output
which corresponds to an adjustable supply duct static
pressure of 0.3" w.c. to 2.5" w.c. respectively with a
deadband adjustment range from 0.2" w.c. to 1.0" w.c.
The setpoint is adjustable on the RTAM Static Pressure
Setpoint potentiometer or through ICS.
Example:
Supply Duct Static setpoint = 2.0" w.c. (RTAM)
Deadband = 0.2" w.c. (RTAM)
Duct Static Control Range = 1.9" w.c. to 2.1" w.c.
Figure 45. Output vs. input
Transducer Voltage Output vs Pressure Input
0.0
0.5
1.0
1.5
2.0
2.5
3.0
3.5
4.0
4.5
-0.5 0.0 0.5 1.0 1.5 2.0 2.5 3.0 3.5 4.0 4.5 5.0 5.5
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:
• None - When RTAM DIP Switch #3 and #4 are in the
“Off” position, no reset will be allowed.
• Reset based on Return Air Temperature - When
RTAM DIP Switch #3 is “Off” and Switch #4 is “On”,
a selectable supply air reset setpoint of 50°F to 90°F
via a unit mounted potentiometer or Tracer™ is
permissible.
• Reset based on Zone Temperature - When RTAM
DIP Switch #3 is “On” and Switch #4 is “Off”, a
selectable supply air reset setpoint of 50°F to 90°F
via RTAM potentiometer or Tracer is permissible.
• Reset based on Outdoor Air Temperature - When
DIP Switch #3 and #4 are “On”, a selectable supply
air reset setpoint of 0°F to 100°F via RTAM
potentiometer or Tracer is permissible.
VAV Supply Air Tempering (Only
Available with Modulating Gas Heat)
The gas heater will be modulated to prevent the
Discharge Air Temperature from falling below the
Discharge Temperature Deadband. Upon satisfying the
Supply Air Tempering requirements, a 5 minute SA
Tempering Delay timer will start whenever the
modulating gas heat combustion blower is
commanded to 0 and must time out before the unit will
be allowed to re-enter “Cool” mode. This timer will be
reset to 5 minutes whenever there is an active call for
“Supply Air Tempering”. Tempering will be
discontinued whenever;
• The 5 minutes “Supply Air Tempering Delay” timer
has timed-out and;
• There is an active cooling request for VAV Occupied
Cooling.
Constant Volume or Variable Air
Volume Applications (Single
Zone or Traditional)
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 ““OOffff”” mode from any other
mode, any diagnostic data and diagnostic indication
signal will be retained as long as the system remains in
the ““OOffff”” status. Switching the “System” selector from
the ““OOffff”” mode back to any other mode of operation
will reset all diagnostics.
SSttaarrttuupp
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