System Sensor DH400ACDCIHT User Manual
INSTALLATION AND MAINTENANCE INSTRUCTIONS
WARNING
DH400ACDCIHT Air Duct Smoke Detector
Before Installing
Please thoroughly read the System Sensor Guide for Proper
Use of Smoke Detectors in Duct Applications (A05-1004),
which provides detailed information on detector spacing,
placement, zoning, wiring, and special applications. Copies
of this manual are available online at www.systemsensor.com
or via System Sensor’s toll free fax-back service, Documents
on Demand at 800/736-7672. NFPA Standards 72 and 90A
should also be referenced for detailed information.
NOTICE: This manual should 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.
This detector is intended for use only with the 1451DHHT
detector head (supplied).
Table of Contents Page
[1] General Description 1
[2] Exploded View of Duct Detector Components 2
[3] Contents of the Duct Detector Kit 2
[4] Installation Sequence 2
[5] Duct Detector Maintenance and Test Procedures 8
[6] Detector Cleaning Procedures 9
[7] Specifications 10
[8] DH400 OE-1 Description and Installation 11
Warranty 12
List of Tables and Figures Page
Fig. 1: Duct Detector Exploded View 2
Fig. 2: Installation of Sampling Tube Gaskets 3
Fig. 3: Mounting Location of Speed Nuts 3
Table 1: Inlet Sampling Tube Selection 3
Fig. 4: Inlet Sampling Tube 4
Fig. 5: Sampling Tube Mounting Configurations 4
Fig. 6: Sampling Tube Filter Installation 5
Fig. 7: Wiring Diagram 6
Fig. 8: Wiring Diagram – No Control Panel 7
Fig. 9: Wiring Diagram – Accessories 8
Fig. 10: Testing Detector Alarm 9
Fig. 11: Detector Head Removal 9
Fig. 12: RTS451/RTS451KEY Test Coil Installation 10
Fig. 13: Ion Head Exploded View 10
[1] General Description
An HVAC system supplies conditioned air to virtually every
area of a building. Smoke introduced into this air duct system will be distributed to the entire building. Smoke detectors designed for use in air duct systems are used to sense
the presence of smoke in the duct.
Model DH400ACDCIHT Air Duct Smoke Detectors are supplied with the model 1451DHHT ionization detector head.
This smoke detection method is combined with an efficient
housing design that samples air passing through a duct
and allows detection of a developing hazardous condition.
When sufficient smoke is sensed, an alarm signal is initiated at the fire control panel monitoring the detector, and
appropriate action can be taken to shut off fans and 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 DH400ACDCIHT air duct smoke detector is designed to
operate from 24 VDC, 24 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. This detector is 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 detectors latch into alarm state when alarm occurs.
LEDs on each detector illuminate to provide local alarm
indication, and optional accessories offer a variety of
annunciation capabilities.
The detector can be reset by a momentary power interruption, by the magnet activated reset switch, or by the
optional remote test station.
NOTICE: The DH400ACDCIHT can be installed outdoors
3825 Ohio Avenue, St. Charles, Illinois 60174
1-800-SENSOR2, FAX: 630-377-6495
www.systemsensor.com
using the optional accessory DH400 OE-1.
Please refer to section 9 for a description and
installation instructions.
D400-64-00 1 I56-991-08R
[2] Figure 1. Exploded View Of Duct Detector Components:
SAMPLING TUBE
FILTERS
CONDUIT HOLES
DUCT DETECTOR
HOUSIN
G
TERMINAL STRIP
PC BOARD
INSULATOR
DUCT DETECTOR
COVER
SAMPLING TUBE
MOUNTING
SCREWS
DETECTOR HEAD
EXHAUST
FILTER ADAPTER
DETECTOR BASE
INLET SAMPLING TUBE
(SUPPLIED SEPARATELY)
O-RINGS
FOAM
GASKETS
HOUSING
MOUNTING SCREWS
TEST MAGNET
TUBE
END
PLUG
H0237-00
[3] Contents Of The Duct Detector Kit
1. Complete housing base and cover assembly
2. Two #10 sheet metal mounting screws
3. Two sampling tube filters
4. One test magnet
5. Drilling template
6. Two 5/16 O-rings
7. Two rubber tube bushing seals
8. Four #6 self-tapping mounting screws for the sampling
and optional exhaust tube extension
9. One filter adapter
10. One inlet tube end plug
11. Two #10 speed nuts
12. One test coil and parts bag
NOTE: The inlet sampling tube must be ordered sepa-
rately. It must be the correct length for the width
of the duct where it will be installed. See Table 1
on page 4 to determine the inlet tube required for
different duct widths.
[4] Installation Sequence
Step Page
[4.1] Verify duct air flow direction and velocity 2
[4.2] Drill the mounting holes 3
[4.3] Secure the detector housing to the duct 3
[4.4] Install the sampling tube 3
[4.5] Complete the field wiring 5
[4.6] Install the filters and check pressure differential 5
[4.7] Perform detector check 5
[4.8] Install the cover 8
[4.1] Verify Duct Air Flow Direction And Velocity
Model DH400ACDCIHT 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.
[4.2] 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. Slide the two speed nuts
over the two small holes (hole A) next to the sampling tube
bushing holes (hole B) previously drilled in the duct. (See
Figure 3.)
D400-64-00 2 I56-991-08R
[4.3] Secure The Detector Housing To The Duct
SCREW HOLES FOR ATTACHING
DETECTOR HOUSING TO DUCT
FOAM GASKETS
EXHAUST TUBE
(EXTENSION BUSHING)
DUCT DETECTOR
HOUSING
O-RINGS
MOUNTING
SCREWS
INLET SAMPLING
TUBE BUSHING
HOLE B
HOLE A
DUCT
WALL
SPEED
NUT
WARNING
Remove the duct housing cover. Slide the foam gaskets over
the tube bushings as shown in Figure 2. Make sure the two
small holes in the gaskets line up with the two base mounting holes. Put one 5/16-inch O-ring over each of the two
#10 sheet metal screws. Use the two sheet metal screws to
screw the detector housing to the duct. CAUTION: Do not
overtighten the screws.
Figure 2. Installation of foam gaskets over sampling
tube bushings:
H0238-00
Figure 3. Speed nut mounting location:
Mounting the detector housing in a vertical orientation
is acceptable, provided that the air flows directly into the
sampling tube holes as indicated in Figure 4.
Table 1. Inlet tubes required for dif ferent 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
[4.4.1] Installation For Ducts Less Than 8 Feet Wide
1. If the tube is longer than the width of the air duct, drill
a 3/4-inch hole in the duct directly opposite the hole
already cut for the inlet tube. 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
detector.
2. Slide the tube into the centermost housing bushing.
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 inches of the tube extend
outside 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 when the tube protrudes.
H0116-00
[4.4] Install The Inlet
The inlet tube (shown in Figure 4) is identified by a series
of air inlet holes on the tube. This tube must be purchased
In no case should more than 2 air inlet holes be cut off the
tube. There must be a minimum of 10 holes in the tube
exposed to the air stream.
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 into 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.
[4.4.2] Installation For Ducts More Than 8 Feet Wide
NOTE: To install inlet tubes in ducts more than 8 feet
wide, work must be performed inside the air
duct. Sampling of air in ducts wider than 8 feet
is accomplished by using the ST-10 inlet sampling
tube. If the tube is shorter than the width of the
The inlet tube is always installed in the centermost housing bushing, with air inlet holes facing into the air flow.
To assist proper installation, the tube’s mounting flange is
marked with arrows. Make sure the inlet tube is mounted
air duct, install the end plug into the inlet tube as
shown in Figure 4 and support the end opposite
the duct detector.
so that the arrows point into the air flow. Figure 5 shows
the various combinations of tube mounting configurations
with respect to air flow.
D400-64-00 3 I56-991-08R
Figure 4. Air duct detector inlet sampling tube:
SAMPLING
TUBE
END CAP
AIR HOLES
ARROW
MUST
FACE
INTO AIR FLOW
AIR FLOW DIRECTION
FLANGE
AIR FLOW
DIRECTION
DETECTOR
HOUSING
DOTS INDICATE POSITION OF
SAMPLING TUBE HOLES
AIR FLOW
DIRECTION
DETECTOR
HOUSING
SAMPLING
TUBE
EXHAUST
TUBE
AIR FLOW
DIRECTION
EXHAUST
TUBE
SAMPLING
TUBE
SAMPLING
TUBE
EXHAUST
TUBE
DETECTOR
HOUSING
AIR FLOW
DIRECTION
DETECTOR
HOUSING
A.
B.
C.
D.
HORIZONTAL MOUNTING OF HOUSING
VERTICAL MOUNTING OF HOUSING
Figure 5. Tube mounting configurations with varying air flow direction:
H0108-02
Install the inlet tube as follows:
1. Drill a 3/4-inch hole in the duct directly opposite the
hole already drilled for the inlet tube.
2. Slide the inlet tube with the flange into the centermost
housing bushing. Position the tube so that the arrows
point into the air flow. Secure the tube flange to the
housing bushing with two #6 self-tapping screws.
3. From inside the duct, couple the other section of the
inlet tube to the section already installed using the 1/2inch conduit fitting supplied. Make sure that the holes
on both of the air inlet tubes are lined up and facing into
the air flow.
4. Trim the end of the tube protruding through the duct so
that 1 to 2 inches of the tube extend outside 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 when the tube protrudes.
D400-64-00 4 I56-991-08R
NOTE: An alternate method to using the ST-10 is to use
Air currents inside the duct may cause excessive vibration,
especially when the longer sampling tubes are used. In
these cases a 3 inch floor flange (available at most plumbing supply stores) may be used to fasten the sampling tube
to the other side of the duct. When using the flange/connector mounting technique, drill a 1 inch to 1-1/4-inch hole
where the flange will be used.
two ST-5 inlet tubes. Remove the flange from
one of the tubes and install as described above.
After the installation, use electrical tape to close
off some of the sampling holes so that there is a
total of 10 to 12 holes spaced as evenly as possible
across the width of the duct.
H0109-01
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