7-6495
Before Installing
Please thoroughly read the System Sensor Guide for Proper
Use of Smoke Detectors in Duct Applications (I56-473),
which provides detailed information on detector spacing,
placement, zoning, wiring, and special applications. Copies
of this manual are available from System Sensor. NFPA
Standards 72 and 90A should also be referenced for detailed
information.
NOTICE: This manual shall be left with the owner/user of
this equipment.
IMPORTANT: This detector must be tested and maintained
regularly following NFPA 72 requirements. The detector
should be cleaned at least once a year.
Table of Contents
Page
[1] General Description
1
[2] Limitations of Duct Smoke Detectors
1
[3] Exploded View of Duct Smoke Detector Components 2
[4] Contents of the Duct Smoke Detector Kit
2
[5] Installation Sequence
2
[6] Duct Smoke Detector Maintenance and Test Procedures 5
[7] Detector Cleaning Procedures
7
[8] Board Replacement
8
[9] Specifications
8
Warranty
8
[1] General Description
An HVAC system supplies conditioned air to virtually every
area of a building. Smoke introduced into this air duct sys-
tem will be distributed to the entire building. Smoke detec-
tors designed for use in air duct systems are used to sense
the presence of smoke in the duct.
Model DH100ACDCP Air Duct Smoke Detector utilizes pho-
toelectric technology for the detection of smoke. This
detection method, when combined with an efficient hous-
ing design, samples air passing through the duct and
allows detection of a developing hazardous condition.
When sufficient smoke is sensed, an alarm signal is initiat-
ed at the fire control panel monitoring the detector, and
appropriate action can be taken to shut off fans, blowers,
change over air handling systems, etc. These actions can
facilitate the management of toxic smoke and fire gases
throughout the areas served by the duct system.
The DH100ACDCP detector is designed to operate on 24
VDC/VAC, 120 VAC, or 240 VAC. Alarm and supervisory
relay contacts are available for control panel interface (alarm
initiation), HVAC control, and other auxiliary functions.
Auxiliary relays are also provided for fan shut down or sig-
naling of up to 9 other detectors in the loop for multiple fan
shut down. These detectors are not designed for 2-wire
applications.
For testing, the alarm can be enabled by a magnet activated
test switch or by the optional remote test station. The duct
smoke detector latches into alarm state when an alarm
occurs. A green LED flashes to indicate power, a red LED
signals local alarm indication, and optional accessories
offer a variety of annunciation capabilities.
The DH100ACDCP can be reset by a momentary power
interruption, the reset button on the front cover, the control
panel, or remote reset accessory. The DH100ACDCP incor-
porates a cover tamper feature that provides a trouble sig-
nal after 7 minutes if the cover is removed or improperly
installed. Proper installation of the cover removes the trou-
ble condition.
[2] Limitations Of Duct Smoke Detectors
The National Fire Protection Association has established
that DUCT DETECTORS MUST NOT BE USED AS A SUB-
STITUTE FOR OPEN AREA DETECTOR PROTECTION as a
means of providing life safety. Nor are they a substitute for
early warning in a buildings regular fire detection system.
System Sensor supports this position and strongly recom-
mends that the user read NFPA Standards 90A, 72, and 101.
The DH100ACDCP Air Duct Smoke Detectors are listed per UL
268A.
This device will not operate without electrical power.
Fire situations may cause an interruption of power. The
system safeguards should be discussed with your local fire
protection specialist.
This device will not sense smoke unless the ventilation sys-
tem is operating and the cover is installed.
For this detector to function properly, it MUST be installed
according to the instructions in this manual. Furthermore,
the detector MUST be protected from the elements and
operated within ALL electrical and environmental specifi-
cations listed in this manual. Failure to comply with these
requirements may prevent the detector from activating
when smoke is present in the air duct.
WARNING
WARNING
WARNING
WARNING [4] Contents Of The Duct Smoke Detector Kit
1. Complete housing base and cover assembly
2. Two #10
×1
1 4
sheet metal screws for mounting
3. Two sampling tube filters
4. One test magnet
5. Drilling template
6. Two foam gaskets
7. Four #6-self tapping mounting screws for the metal
sampling tube and optional exhaust tube extension
8. One inlet tube end plug
9. One plastic sampling tube
10. One #8 self-tapping screw for the plastic sampling tube
NOTE: For ducts over 1
1
/
2
feet, longer inlet sampling tubes
must be ordered to complete the installation. They
must be the correct length for the width of the duct
where they will be installed. See Table 1 on page 3
to determine the inlet tube required for different
duct widths.
[5] Installation Sequence
[5.1] Verify Duct Air Flow Direction And Velocity
Model DH100ACDCP detectors are designed to be used in
air handling systems having air velocities of 500 to 4000
feet per minute. Be sure to check engineering specifications
to ensure that the air velocity in the duct falls within these
parameters. If necessary, use a velocity meter to check the
air velocity in the duct.
[5.2] Drill The Mounting Holes
Remove the paper backing from the mounting template
supplied. Affix the template to the duct at the desired
mounting location. Make sure the template lies flat and
smooth on the duct. Center punch holes A and B. Drill the
holes as indicated on the template.
[5.2.1] Sampling Tube Installation for Ducts Less
Than 1
1
/
2
Feet Wide (see Figure 2)
1. Remove the front cover.
2. Slide the plastic sampling tube into the housing bushing.
3. Align the holes in the bushing with the holes in the sam-
pling tube. Make sure there are 6 exposed holes on the
plastic sampling tube. Secure with the #8 self-tapping
screw into the bottom of the permanent tube (shown in
Fig. 1).
NOTE: For ducts greater than 1
1
/
2
feet in width, refer to
sections [5.4.1] and [5.4.2].
Figure 2. Plastic sampling tube
connected to duct smoke detector:
[5.3] Secure The Detector Housing To The Duct
Slide the foam gaskets over the tube bushings as shown in
Figure 3. Use the two 1
1 4
long sheet metal screws to screw
the detector housing to the duct.
CAUTION: Do not overtighten the screws.
D100-68-00
2
I56-1147-11R
[3] Figure 1: Exploded View Of Duct Smoke Detector Components
FOAM
GASKETS
PLASTIC
SAMPLING TUBE
CONDUIT HOLES
DETECTOR
HOUSING
TERMINAL STRIP
DETECTOR
COVER
SAMPLING TUBE
FILTERS
COVER MOUNTING
SCREWS
PLASTIC SAMPLING TUBE
SELF-TAPPING SCREW
POWER BOARD
DETECTOR BOARD Figure 3. Installation of foam gaskets over sampling
tube bushings:
A78-2045-00
[5.4] Sampling Tube Installation for Ducts Greater
Than 1
1
/
2
Feet Wide
The sampling tube is identified by a series of air inlet holes
on the tube. A plastic tube is included for ducts up to 18 in width. All other lengths must be purchased separately.
Order the correct length, as specified in Table 1, for width
of the duct where it will be installed. The exhaust tube is
molded onto the base of the duct housing, and the A2440-
00 Exhaust Tube Extension is available as an accessory in
those cases where the molded exhaust port does not extend
at least 2 inches into the duct.
The inlet tube is always installed with the air inlet holes
facing into the air flow. To assist proper installation, the
tubes mounting flange is marked with arrows. Make sure
the inlet tube is mounted so that the arrows point into the
air flow (see Figure 4). Figure 5 shows the various combi-
nations of tube mounting configurations with respect to air
flow. Mounting the detector housing in a vertical orienta-
tion is acceptable, provided that the air flows directly into
the sampling tube holes as indicated in Figure 4.
Table 1. Inlet tubes required for different duct
widths:
Outside Duct Width
Inlet Tube Required
1 to 2 ft.
ST-1.5
2 to 4 ft.
ST-3
4 to 8 ft.
ST-5
8 to 12 ft.
ST-10
[5.4.1] Installation For Ducts Greater Than 1
1
/
2
Feet
But Less Than 8 Feet Wide
1. If the tube is longer than the width of the air duct, drill a
3
/
4
hole in the duct opposite the hole already cut for the
inlet tube. Make sure the hole is
1 to 2 below the inlet
hole on the opposite side of the duct to allow moisture
drainage away from the detector. If the tube is shorter
than the width of the air duct, install the end plug into the
inlet tube as shown in Figure 4. Sampling tubes over 3 ft.
long must be supported at the end opposite the duct
smoke detector.
2. Slide the tube into the housing bushing that meets the
air flow first. Position the tube so that the arrows point
into the air flow.
3. Secure the tube flange to the housing bushing with two
#6 self-tapping screws.
4. For tubes longer than the width of the air duct, the tube
should extend out of the opposite side of the duct. If
there are more than 2 holes in the section of the tube
extending out of the duct, select a different length using
Table 1. Otherwise, trim the end of the tube protruding
through the duct so that 1
to 2 of the tube extend out-
side the duct. Plug this end with the end plug and tape
closed any holes in the protruding section of the tube. Be
sure to seal the duct where the tube protrudes.
Figure 4. Air duct detector inlet sampling tube:
A78-2047-00
Figure 5. Tube mounting configurations with varying
air flow directi