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not update at least every 24 minutes will
be viewed as failed.
Composite zone temperatures and
thumbwheel settings are derived from
the transmitted data and the hardwired
sensor if applicable. Data for the zone
temperature and thumbwheel value
comes first from the averaging sensors
then the primary backup, then the
secondary backup. Zone temperature is
the simple average of the available
sensors. The thumbwheel setting is the
weighted average of the available
sensors.
zone temperature = (measured
temperature + zone temperature
correction)/(Number of sensors)
thumbwheel setting = ((thumbwheel
setting + thumbwheel
correction)*weighting factor))/(weighting
factor)
Flow (or Supply Pressure in the case of
bypass damper mode)
Each VAV valve contains a "flow ring. " It
is a multi-ported Pitot tube. The differen-
tial flow transducer connects to the flow
ring. One side of the flow ring is exposed
to the duct static pressure, the other is
exposed to static and velocity pressure.
The difference is velocity pressure. By
knowing the air velocity in the duct and
the size of the air valve, the air volume
can be calculated. See Chapter 7 for Air
Balancing Procedures.
UCM STATUS
The status display does not contain any
editable data. If Communications are
down (UCM NOT COMMUNICATING is
shown), the rest of the status display will
not appear. Note: The following screen
shots are taken from Trane EveryWare™
Software (Eware). When communicating
with a UCM 4.0 or greater via Eware,
you must have Eware software revision
1.35 or greater. The display will be similar
when using a CCP . However, when
communicating to VAV UCM using
Tracer Summit, although the display will
be completely different, the various
functions of the UCM perform the same.
Please reference the VariTrac Operators
Guide or the Tracer Summit System
Programming Guide (BMTW-SVP01A-
EN) for exact CCP and Summit (respec-
tively) displays.
18
UCM Programming
and Operation
When viewed from the Eware, the UCM status display appears as follows:
Following are descriptions of each line on the UCM status screen.
Zone Temperature
This line displays the temperature as recorded by the zone sensor. If the zone sensor
has failed, this line will read FAIL.
Active Cooling Set Point and Active Heating Set Point
These set points are the active (actual) cooling and heating set points currently used
by the UCM. If the zone sensor is enabled, the zone sensor set point will be used as
the Active Cooling set point during occupied mode.
Control Mode
This line shows whether the UCM is in the occupied or unoccupied mode. The
control mode determines which heating and cooling set points to use.
Control Action
This line shows the heat or cool control action of the UCM. The cool control action
will modulate the air valve as if the supply duct air is colder than the space tempera-
ture. The heat control action will modulate the air valve opposite the cool control
action (supply duct air is warmer than the space temperature).
Flow
This line displays the unit's airflow rate expressed in the flow units selected in the
setup menu. This line will not be shown if the UCM is using position control instead
of flow control. The UCM will use position control if the flow sensor is failed or not
installed. The UCM will also use position control if the unit's airflow rate is less than
5% or greater than 110% of the unit's cataloged CFM. For example, the UCM will use
position control for a size 600 CFM unit if the flow is less than 30 CFM (5%) or greater
than 660 CFM (110%). NOTE: Although the UCM will read flow down to 5% of
cataloged and up to 110% of cataloged, the range of MIN FLOW settings is 0%, or
10% to 100% of cataloged. The range of MAX FLOW settings is 100% of cataloged. In
the example above, the lowest allowable MIN FLOW set point is 60 CFM (zero is also
permissible) and 600 CFM is the highest allowable MAX FLOW set point.
Flow Control
This line displays the actual flow control override of the UCM. These overrides can be
AUTO, OPEN, CLOSED, MIN, and MAX.
Position
This line displays the UCM's air valve position.
VAV-SVX01B-EN
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