Trane HUV Installation Operation & Maintenance page 27

Two Systems in One
In an ICS environment, the ZN520
is pre-designed to install quickly
and easily into the system. Since
the controller and the unit are fac-
tory tested and commissioned, the
start-up time for the entire system
is minimized. Trane becomes the
single source of responsibility for
the equipment, unit controls, and
building automation system.
As a standalone controller, the
ZN520 is ideally suited for fix-on-
fail replacement of units with old
pneumatic controllers, or in situa-
tions where a BAS will be added at
a later date. Once power is applied
to the controller, it will automati-
cally start up and run based upon
the setpoint on the local zone sen-
sor. An individual time clock can
be added to the unit for local
scheduling.
UV-PRC001-EN
Controls
Tracer ZN520
The ZN520 is certified to the in-
teroperable LonMark Space Com-
fort Controller profile. This allows
the controller to be used with an-
other vendor's BAS and thereby
still provide the high quality of fac-
tory installation and testing. In ad-
dition, the ZN520 provides one of
the most extensive interoperable
data lists of any controller of its
type in the industry.
Tracer ZN520 features in-
clude:
Automatic Fan and Ventilation
Reset
The ZN520 can be selected to auto-
matically choose the best fan
speed for the classroom load. The
goal is to keep the fan speed as
low as possible and thereby mini-
mize air noise to the occupants. In
the conjunction with this feature,
the controller can automatically
adjust the outside air damper with
changes in fan speed. This helps
maintain the proper amount of
ventilation air to the occupants in-
dependent of the fan speed.
Active Dehumidification
On unit ventilators with reheat
coils, the ZN520 can provide active
dehumidification to the class-
room. This means that the
classroom relative humidity can
be kept below an adjustable set-
point independent outdoor weath-
er conditions. Indoor humidity
levels are recommended by
ASHRAE to be kept below 60% in
order to minimize microbial
growth and the life span of air-
borne illness causing germs.
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