Catalogue

50 UV-PRC004-EN
Controls
a later date. Once power is applied to the controller, it will automatically start up and run based
upon the setpoint on the local zone sensor. An individual time clock can be added to the unit for
local scheduling. The Tracer UC400 is BTL listed as B-ASC profile. This ensures the controller to be
used with other BACnet
®
building automation systems.
Tracer UC400 Features Include
Single Zone VAV with Fully Modulating Fan Speed. The Tracer UC400 will minimize fan
speed, and in turn energy usage, by only delivering the air flow needed.
Ventilation Reset. With the Tracer UC400 the unit ventilator delivers the airflow the space needs.
When the air flow adjusts the outside air damper will also adjust to satisfy the space needs. This
helps maintain the proper amount of ventilation air to the occupants independent of the fan speed.
As part of the ventilation strategy, the controller will reposition the outside air damper to confirm
the minimum outside airflow is met at both operating conditions.
Filter Maintenance. Filter status for the controller is based on the cumulative run hours of the
unit fan. The controller compares the amount of fan run time against an adjustable fan run hour
(stored in the controller) to determine when maintenance is recommended for the unit. The run-
hours value may be user edited as required. The valid range for the fan run hours limit is 0 to
5000 hours with a default of 600 hours. Once the run hours limit has been exceeded, the controller
generates a maintenance required diagnostic (unit will not shut-down). The user will be notified
of this diagnostic through the building automation system or when a Trane
®
service tool is
communicating with the controller.
Active Dehumidification. On unit ventilators with reheat coils, the controller can provide active
dehumidification to the classroom. This means that the classroom relative humidity can be kept
below an adjustable setpoint independent outdoor weather conditions. Indoor humidity levels are
recommended by ASHRAE to be kept below 60 percent in order to minimize microbial growth and
the life span of airborne illness causing germs.
Hydronic Coil Freeze Protection (Freeze Avoidance). Unit ventilator systems in cold
climates need to take precautions to avoid hydronic coil freeze-up. The controller does this from
three different aspects. Any of these methods of protections will result in the unit fan being
disabled, the outside air damper being shut, and the hydronic valves being opened 100 percent.
The three methods of freeze avoidance include:
1. A binary freeze protection thermostat is mounted on the coil and will cause a latching diagnostic
if the coil temperature falls below 35°F.
Figure 16. Cool mode nominal hydronic cooling control
t
(°F)
80
Fa
n
Max. Flow = 100%
100
s
etpoin
t
70
80
60
n
speed
0
100
%
Cooling
e
temp
s
60
40
comma
n
0

100
%
Cooling
20
ischarg
e
50
n
d (%)
Min. discharge
setpoint = 50°F
Min. Flow = 0%
0
D
45
Csp
Siblld
No cooling load
Design cooling
load (demand)
S
pace sens
ibl
e
l
oa
d
load
(demand)
Tracer UC400
UV-PRC004-EN.book Page 50 Monday, February 4, 2013 11:01 AM