Trane HUV Installation Operation & Maintenance page 32

3 2
Controls
TUC
Dirty Filter Proof
The TUC controller provides posi-
tive proof of a dirty filter via a dif-
ferential pressure switch. The
pressure switch contains two
ports that reside on each side of
the air filter. Unlike the ZN520
(which tracks fan time usage), the
TUC control system gives the own-
er positive proof of air resistance
through the filter to notify the
building owner of a filter mainte-
nance situation
Active Humidity Control
Trane's active dehumidification
control strategy automatically de-
termines the proper control se-
quence and continuously resets
the unit ventilator's leaving air
temperature, as needed, to man-
age both the temperature and the
relative humidity sensed in the
space. This approach overcomes
the deficiencies of other means of
control based on temperature
alone.
The active dehumidification con-
trol, which includes a cooling coil
with post conditioning (reheat)
control, is available with the TUC.
The algorithms associated with
this control option are specifically
designed to govern both space
temperature and relative humidi-
ty. These algorithms minimize the
amount of reheat needed to main-
tain the space humidity below a
preset limit. Reheat is used only
when required, and is operated in
the most energy efficient manner
for the system. This reheat energy
can be recovered from the chilled
water system (most preferred), or
provided as a new energy. See the
Engineering Bulletin:
UV-EB-11-497 (EN) for Active
Humidity Control with Unit Venti-
lator Systems.
Modulating Valve Control
Configuration of a modulating an-
alog actuator is possible with the
TUC control selection. Unlike the
ZN520 which controls as 2-posi-
tion and 3-wire floating, the TUC
allows a field supplied analog volt-
age input from 0 to 10-volts (also,
4 to 20 mA, 2 to 10-volts, 1 to 5
VDC) to drive outside air control,
and water valve control for true
modulation of an outside air
damper and/or coil control.
UV-PRC001-EN