Installation and Maintenance Manual

Startup
102 UNT-SVX07D-EN
section, “Manual Fan Speed Control (UC400)”).
AUTO Fan Operation; ECM Acoustical Mode
(UC400)
When the controller is configured for Acoustical Mode, by
means of the Fan Operating Mode Request MV point, the
controller and daughter board will minimize acoustical
nuisance by balancing changes in fan speed and total fan
noise. The controller will fully OPEN cooling and heating
valves before increasing fan speed to meet space
temperature (unless the fan has been manually controlled.
Refer to the preceding section, “Manual Fan Speed
Control (UC400)”). If multiple stages of electric heat exist
the controller will use a single minimum air flow for each
stage.
Exhaust Control (UC400)
Exhaust control is achieved by a single-speed exhaust fan
and controlled by binary output 2 (BO2). Exhaust control,
if not present, can be enabled by selecting Ye s under the
Exhaust Fan Selection on the Tracer TU Configuration
page under the Equipment Options group.
Note: Exhaust fan configuration cannot be selected with
3-speed fan operation.
Important: If exhaust control is added to an existing
configuration, all other configuration
options should be verified to match the
correct equipment options.Temperature
and flow setpoints will revert to default
values.
The exhaust function is coordinated with the supply fan
and outdoor/return air dampers as follows:
• The exhaust fan energizes when the fan is running and
when the outdoor air damper position is greater than
or equal to the exhaust fan enable position (or the
outside air damper position at which the exhaust fan
turns ON).
• The exhaust fan turns OFF w
hen the fan either turns
OFF or the outdoor air damper closes to 10 percent
be
low the exhaust fan enable position.
• If the exhaust fan/damper enable setpoint
is less than
10 percent, the exhaust output is energiz
ed if the
outdoor air damper position is at the setpoint and de-
energized at 0.
Valve Operation (UC400)
The UC400 controller supports one or two modulating or
two-position valves, depending on the application (refer
Table 34, p. 103). The controller opens and closes the
appropriate valve(s) to maintain the active zone
temperature setpoint at the heating setpoint in heating
mode or the cooling setpoint in cooling mode (refer to
“Cascade Zone Control,” p. 100).
Modulating Valve Operation (UC400)
The UC400 controller supports tri-state modulating valve
control. Two binary outputs control each valve: one to
drive the valve open and one to drive the valve closed. The
stroke time for each valve is configurable using the Tracer
TU service tool. The controller supports the following:
•Heating
• Cooling
• Heat/cool changeover with a single
valve and coil for 2-
pipe applications
• Cooling or heat, cool changeo
ver with the main valve,
and coil
• Only heating with the auxiliary valve and coil for 4-pipe
ap
plications
The controller moves the modulating valve to the desired
po
sitions based on heating or cooling requirements.
Modulating Valve Calibration (UC400)
Modulating valve calibration is automatic. During normal
controller operation, the UC400 overdrives the actuator
(135 percent of the stroke time) whenever there is a
request for a position of 0 percent or 100 percent. At either
power-up, after a power outage, or when the occupancy
status changes to unoccupied, the controller first drives all
modulating valves (and dampers) to the closed position.
The controller calibrates to the fully CLOSED position by
over driving the actuator (135 percent of the stroke time).
Thereafter, the controller resumes normal operation.
Two-position Valve Operation (UC400)
The UC400 controller supports two-position valves with a
single binary output for each valve. Controllers used for
2-pipe applications support heating, cooling, or heat/cool
changeover with a single valve/coil. A controller used for
4-pipe applications supports cooling or heat/cool
changeover with a main valve/coil and heating only with
an auxiliary valve/coil.
Modulating Outdoor/Return Air Damper
(UC400)
The UC400 controller operates the modulating outdoor/
return air dampers based on the following:
• Occupancy mode
• Outdoor air temperature (com
municated or hard wired
sensor)
• Zone temperature
•Setpoint
• Discharge air temperature
• Discharge air temperature setpoint
The minimum position for an outdoor air damper is
con
figurable using the Tracer TU service tool for both
occupied mode and occupied standby mode and for low-
UNT-SVX07_-EN.book Page 102 Friday, April 27, 2012 9:40 AM