17
Maintenance
Periodically test the GFCI receptacle by pressing the
TEST button on the face of the receptacle. This should
cause the internal circuit of the receptacle to trip and open
the receptacle. Check for proper grounding wires a nd
power line phasing if the GFCI receptacle does not trip as
required. Press the RESET but ton to clear the tripped
condition.
Fuse On Powered Type
The factory fuse is a Bussman “Fusetron” T--15,
non--renewable screw--in (Edison base) type plug fuse.
Using Unit--Mounted Conven ience Outlets
Units with unit--mounted convenience outlet circuits will
often require that two disconnects be opened to
de--energize all power to the unit. Treat all units as
ele ctrically energized until the convenienc e outl et power
is also checked and de --energization is confirmed. Observe
Nationa l Electrical Code Article 210, Branch Circuit s, for
use of conveni ence outlets.
SMOKE DETECTORS
Smoke detectors are available as factory--i nstalled options
on 48TC mode ls. Smoke detectors may be specifie d for
Supply Air only or for Return Air without or with
econom izer or in combination of Supply Air and Return
Air. Return Air smoke detectors are arranged for vertical
return configurations only. All components necessary for
operation are factory--provided and mounted. The unit is
factory--configured for immediate smoke detector
shutdown operation; additional wiring or modifications to
unit terminal board may be necessary to complete the unit
and smoke detector configuration t o meet proj ect
requirements.
System
The smoke det ector system consists of a four--wire
controller and one or two sensors. Its prim ary function is
to shut down the rooftop uni t in order to prevent smoke
from cir culating throughout the building. It is not to be
used as a life saving device.
Controller
The controller (see Fig. 18) includes a controller housing,
a printed circuit board, and a clear pla stic cover. The
controller can be connected to one or two compatible duct
smoke sensors. The clear plastic cover is secured to the
housing with a single captive screw for easy access to the
wiring terminals. The c ontroller has three LEDs (for
Power, Trouble and Alarm) and a manual test/reset butt on
(on the cover face).
Duct smoke sensor
controller
Fastener
(2X)
Controller cover
Conduit nuts
(supplied by installer)
Conduit support plate
Cover gasket
(ordering option)
Conduit couplings
(supplied by installer)
Terminal block cover
Controller housing
and electronics
Alarm
Power
Te s t / r e s e t
switch
Troub le
C08208
Fig. 18 -- Controller Assembly
Sensor
The sensor (see Fig. 19) includes a plastic housing, a
printed circuit board, a clear plastic cover, a sampling
tube inlet and an exhaust tube. The sampling tube (when
used) and exhaust tube are attache d during installation.
The sampling tube vari es i n l ength depending on the size
of the rooftop unit. The clear plastic cover permits visual
inspections without having to disassemble the sensor. The
cover attac hes to the sensor housing using four captive
screws and forms an airti ght chamber around the sensing
electronics. Each sensor includes a harness with an RJ45
terminal for connecting to the controller. Ea ch sensor has
four LEDs (for Power, Trouble, Alarm and Dirty) and a
manua l test/reset button (on the left--side of the housing).
Air is introduced to the duct smoke detector sensor’s
sensing chamber through a sampling tube tha t extends into
the HVAC duct and is directed back into the ventilation
system through a (shorter) exhaust tube. The difference in
air pressure between the two tubes pulls the sampled air
through the se nsing chamber. When a sufficient amount of
smoke is detected in the sensing chamber, the sensor
signals an alarm state and the controller automatically
take s the appropriate ac tion to shut down fans and
blowers, change over air handling systems, notify the fire
alarm control panel, etc.
48TC
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