Chapter 4 - Ucm 4.0 Programming And Operation; Typical Ucm Operating Behavior - Trane UCM 4.0 and WirelessVAV Communication Installation/ Operator Programming

Chapter Overview
This chapter contains information
about the following:
— Typical UCM Operating Behavior
— UCM Status
— UCM Set Points
— UCM Setup
14
UCM Programming
and Operation
CHAPTER 4: UCM PROGRAMMING & OPERATION
Typical UCM Operating
Behavior
VariTrac Bypass Damper Mode of
operation
In the VariTrac Bypass Damper mode of
operation, the decisions of damper
position are made by a higher-level
system controller, e.g., the VariTrac 4.0
Central Control Panel (CCP). The
VariTrac bypass mode supports the
reporting of supply air temperature
(SAT), supply air static pressure (SAP),
and supply air CO concentration
2
(CO2). This mode supports the follow-
ing:
— Control of damper position from the
higher-level system controller.
— The control of the damper to a failsafe
bypass position upon lack of
communication to the VAV UCM for a
period of one minute.
— Damper calibration from the fully open
position while the system fan is off.
— Upon power up, damper calibration
and then damper movement to its
failsafe bypass position.
— By convention of the VariTrac 4.0
system, DIP switch setting of 63 has
been reserved for the VariTrac Bypass
Damper. Note: DIP switch setting 63 can
be used for non-VariTrac systems.

Typical UCM Operating Behavior

VariTrane and VariT rac (zone damper,
not bypass damper) Modes of
operation
Unoccupied Mode:
Zone temperature is controlled to the
unoccupied set points. If the AHU
system fan is off the valve will be
operating in a pressure dependent
mode.
Normally the minimum flow set point is
not enforced. This allows the control
algorithm to close the valve in response
to zone temperature and set points. If
the minimum flow set points are being
enforced the valve will position itself at
a percentage equivalent to the
minimum flow set point.
Morning Warm Up:
Tracer Summit places the UCM in heat
mode and drives the UCM to maximum
flow. The AHU system fan is turned on
and the UCM operates in pressure
independent mode and controls the
airflow to the maximum flow set point.
NOTE: VariTrac units always operate in
pressure dependent mode.
Morning Cool Down:
Tracer Summit places the UCM into
cool mode and drives the UCM to
maximum flow. The AHU system fan is
turned on and the UCM operates in
pressure independent mode and
controls the airflow to the maximum
flow set point. NOTE: VariTrac units
always operate in pressure dependent
mode.
Occupied:
Zone temperature is controlled to the
occupied set points. Set points are
determined from the local thumbwheel
if enabled.
Cooling:
Zone temperature is controlled to the
cooling set point. Both types of reheat
(hot water and electric) are available if
needed to keep the zone from cooling
below the heating set point.
Heating:
Zone temperature is controlled to the
heating set point. Hot water reheat will
always be available if needed to keep
the zone from cooling below the
heating set point. Electric reheat may be
permitted to turn on if using auto
changeover and the supply air temp (or
auxiliary temperature for stand-alone
units) is not too high.
The following table briefly describes the
typical behavior of various UCM
configurations during normal operating
modes.
VAV-SVX01B-EN