Carrier 48LC 14, Инструкции по обслуживанию и техническому обслуживанию

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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 and power line phasing if the GFCI receptacle
does not trip as required. Press the RESET button to clear the
tripped condition.
Fuse On Powered Type
The factory fuse is a Bussman
1
“Fusetron” T-15, non-renewable
screw-in (Edison base) type plug fuse.
Using Unit-Mounted Convenience Outlets
Units with unit-mounted convenience outlet circuits will often re -
quire that two disconnects be opened to de-energize all power to
the unit. Treat all units as electrically energized until the conve -
nience outlet power is also checked and de-energization is con -
firmed. Observe National Electrical Code Article 210, Branch Cir -
cuits, for use of convenience outlets.
SMOKE DETECTORS
Smoke detectors are available as factory-installed options on
48LC models. Smoke detectors may be specified for supply air
only, for return air without or with economizer, or in combination
of supply air and return air. Return-air smoke detectors are ar -
ranged 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 to meet project requirements.
System
The smoke detector system consists of a four-wire controller and
one or two sensors. Its primary function is to shut down the roof -
top unit in order to prevent smoke from circulating 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 print -
ed circuit board, and a clear plastic 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 controller has three
LEDs (for Power, Trouble and Alarm) and a manual test/reset but -
ton (on the cover face).
Fig. 18 — Controller Assembly
Sensor
The sensor (see Fig. 19) includes a plastic housing, a printed cir -
cuit board, a clear plastic cover, a sampling tube inlet and an ex -
haust tube. The sampling tube (when used) and exhaust tube are
attached during installation. The sampling tube varies in length de -
pending on the size of the rooftop unit. The clear plastic cover per -
mits visual inspections without having to disassemble the sensor.
The cover attaches to the sensor housing using four captive screws
and forms an airtight chamber around the sensing electronics.
Each sensor includes a harness with an RJ45 terminal for connect -
ing to the controller. Each sensor has four LEDs (for Power, Trou -
ble, Alarm and Dirty) and a manual 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 that 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 sensing chamber. When a suffi -
cient amount of smoke is detected in the sensing chamber, the sen -
sor signals an alarm state and the controller automatically takes
the appropriate action to shut down fans and blowers, change over
air handling systems, notify the fire alarm control panel, etc. The
sensor uses a process called differential sensing to prevent gradual
environmental changes from triggering false alarms. A rapid
change in environmental conditions, such as smoke from a fire,
causes the sensor to signal an alarm state but dust and debris accu -
mulated over time does not.
For installations using two sensors, the duct smoke detector
does not differentiate which sensor signals an alarm or trouble
condition.
1. Bussmann is a trademark of Cooper Technologies Company.
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
Test/reset
switch
Trouble