Technical Bulletin
4
SuperDuct Conventional Two-Wire Duct Smoke Detector
Model Description
SD-MAG
Test magnet kit
SD-VTK
Air velocity test kit
Operation
Controls and indicators
Magnetic
test
switch
Alarm
Trouble
Dirty
Figure 3: Duct smoke detector controls and indicators
The controls and indicators on the duct smoke detector (see
Figure 3) are as follows:
Control or indicator
Description
Magnetic test switch
Used to alarm test the detector,
determine its dirty level, and
determine if the detector is in the
trouble state
Alarm LED
Indicates the detector is in the alarm
state
Trouble LED
Flashes once to indicate the detector
is in the trouble state. Requires
manual activation from user.
Dirty LED
Flashes 1 to 4 times to indicate the
detector’s dirtiness level. Requires
manual activation from user.
Normal state
The duct smoke detector operates in the normal state in the
absence of any trouble conditions and when its sensing
chamber is free of smoke or an alarm test is initiated.
Alarm state
The duct smoke detector enters the alarm state (is activated)
when the amount of smoke in its sensing chamber exceeds its
alarm threshold setting or when an alarm test is initiated. Upon
entering the alarm state, the duct smoke detector’s:
•
Alarm LED turns on
•
Common alarm relay contact switches position
•
Remote alarm LED output turns on (is activated)
In addition, the duct smoke detector places a low impedance
short across the initiating device circuit. The low impedance
short causes the control panel’s IDC input to generate an
alarm or supervisory event message depending on the device
type with which it is configured.
Trouble state
The duct smoke detector enters the trouble state under the
following conditions:
•
Its cover is removed and 20 minutes pass before it is
properly secured
•
Its environmental compensation limit is reached
•
The detector is 100% dirty
•
An internal detector fault is present
The duct smoke detector does not automatically indicate
trouble conditions. Instead, you must test whether a trouble is
present. For more information, see “Troubleshooting.”
Note:
All troubles are latched by the duct smoke detector. You
must clear the trouble condition then reset the control panel in
order to restore the detector to its normal state.
Installation
Installation guidelines
To ensure correct operation, install the duct detector using the
following guidelines:
•
Locate the detector so its sampling tube is positioned in a
straight length of square duct between six and ten duct
widths from any bends or obstructions as shown in the
diagram below. See Figure 7 for detector dimensions.
