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
[5.4.3] Modifications Of Inlet Sampling Tubes
SAMPLING TUBE
FILTERS
SAMPLING TUBE
MOUNTING
SCREW
S
DETECTOR HEAD
EXHAUST
FILTER ADAPTER
DETECTOR BASE
INLET SAMPLING TUBE
FOAM GASKET
CAUTION
There may be applications where duct widths are not what
is specified for the installation. In such cases, it is permissible to modify an inlet sampling tube that is longer than
necessary to span the duct width.
[5.6] Install The Filters
To install the sampling tube filters, simply push the filter
adapter into the exhaust tube, and push the filter onto the
adapter tube on the left, as shown in Figure 9. Install the
other filter over the end of the inlet sampling tube.
Use a 0.193-inch diameter (#11) drill and add the appropriate number of holes so that the total number of holes
exposed to the air flow in the duct is 10 to 12. Space the
additional holes as evenly as possible over the length of
the tube.
[5.5] Field Wiring
Wiring Installation Guidelines
All wiring must be installed in compliance with the National
Electrical Code and the local codes having jurisdiction.
Proper wire gauges should be used. The conductors used
to connect smoke detectors to control panels and accessory
devices should be color-coded to reduce the likelihood of
wiring errors. Improper connections can prevent a system
from responding properly in the event of a fire.
For signal wiring, (the wiring between interconnected
detectors or from detectors to auxiliary devices), it is usually recommended that single-conductor wire be no smaller
than 18 gauge. The duct detector terminals accommodate
wire sizes up to 14 gauge. The last foot of conduit should
be flexible steel conduit (available in electrical supply
houses), which facilitates installation and puts less strain
on the conduit holes in the housing. Solid conduit connections may be used, if desired.
Figure 6. Sampling tube filter installation:
H0239-00
Filters require periodic cleaning or replacement, depending on the amount of dust and dirt accumulated. Visually
inspect the filters at least quarterly; inspect them more
often if the dust accumulation warrants it. See Section [6]
for more information. Replacement filters can be ordered
from System Sensor, 3825 Ohio Ave., St. Charles, IL 60174.
(Exhaust tube/intake tube filter P/N F36-05-00).
Smoke detectors and alarm system control panels have
specifications for allowable loop resistance. Consult the
control panel manufacturer’s specifications for the total
loop resistance allowed for the particular model control
panel being used before wiring the detector loop.
Wiring Instructions
The DH400ACDCIHT duct detector is designed for easy
wiring. The housing provides a terminal strip with clamping plates. Wiring connections are made by stripping about
3/8-inch of insulation from the end of the wire, sliding the
bare end under the plate, and tightening the clamping plate
screw.
The detector may be wired for interconnection to UL listed
control panels, or for stand alone service per NFPA 90A.
Refer to the wiring diagrams of Figures 6, 7, and 8 to select
the appropriate circuit for your application.
[5.7] Perform Detector Check
1. Perform the STANDBY AND TROUBLE TEST per Section
[6.2.1].
2. Perform the MAGNET TEST per Section [6.2.2.1]. The
RTS451 test of Section [6.2.2.2] may substitute for this
requirement.
3. Perform the AIR FLOW TEST per Section [6.1.1].
4. Perform the SMOKE RESPONSE TEST per Section
[6.1.2].
5. Perform the SENSITIVITY TEST per Section [6.2.3].
6. Record all test results in the Detector Test Log at the end
of this manual.
[5.8] Install The Cover
Install the cover using the four screws that are fixed in the
housing cover. Be certain filters are installed as specified
in Section [5.6]. Make sure that the cover fits into the base
groove and that all gaskets are in their proper positions.
Tighten the four screws to 10 in-lbs.
D400-64-00 5 I56-991-08R
24V
120
VAC
220/240
VAC
1
2 1
2
13 14
AVAILABLE POWER INPUTS
ALARM AUXILIARY CONTACTS
FOR FAN SHUTDOWN, ETC.
15
16
17
18
19 20
N.C.
C.N.O.
N.O.C.
N.C.
ALARM AUXILIARY CONTACTS SHOWN IN
STANDBY. CONTACTS TRANSFER DURING
ALARM AS INDICATED BY THE ARROWS.
TROUBLE CONTACTS
TROUBLE CONTACTS CLOSED IN ALARM AND STANDBY.
CONTACTS OPEN WHILE DETECTOR HEAD OR POWER IS
REMOVED, AND DURING RESET. OPEN CONTACTS
SIGNAL TROUBLE CONDITION TO PANEL.
24V
120
VAC
220/240
VAC
1 2
12
13
14
AVAILABLE POWER INPUTS
ALARM AUXILIARY CONTACTS
FOR FAN SHUTDOWN, ETC.
15 16
17
18
19
20
N.C.
C.
N.O.
N.O.
C.
N.C.
ALARM AUXILIARY CONTACTS SHOWN IN
STANDBY. CONTACTS TRANSFER DURING
ALARM AS INDICATED BY THE ARROWS.
TROUBLE CONTACTS
TROUBLE CONTACTS CLOSED IN ALARM AND STANDBY.
CONTACTS OPEN WHILE DETECTOR HEAD OR POWER IS
REMOVED, AND DURING RESET. OPEN CONTACT
S
SIGNAL TROUBLE CONDITION TO PANEL.
11
10
11
10
8
9
ALARM
INITIATION
CONTACTS
CONTACTS SHOWN
OPEN IN STANDBY.
CONTACTS CLOSE
IN ALARM.
8
9
ALARM
INITIATION
CONTACTS
CONTACTS SHOWN
OPEN IN STANDBY.
CONTACTS CLOSE
IN ALARM.
ALARM
INITIATION
LOOP
UL LISTED
CONTROL PANEL
FIRST DETECTOR IN THE LOOP
DH400ACDCIHT
LAST DETECTOR IN THE LOOP
DH400ACDCIHT
EOL RESISTOR
SPECIFIED BY
PANEL MANUFACTURER
CONNECT POWER SOURCE
TO APPROPRIATE TERMINALS
OF EACH DETECTOR. SEE
SPECIFICATIONS FOR
ADDITIONAL POWER SUPPLY
INFORMATION.
FOR WIRING OF AUXILIARY
DEVICES, REFER TO
MANUFACTURER'S
INSTALLATION INSTRUCTIONS
OR CONTACT MANUFACTURER.
POWER INPUTS ACCEPT
24 VDC, 24 VAC 50-60 HZ,
120 VAC 50-60 HZ, OR
220/240 VAC 50-60 HZ.
CONNECT POWER SOURCE
TO APPROPRIATE TERMINALS
OF EACH DETECTOR.
AUX. CONTACT RATINGS
10A @ 30 VDC RESISTIVE
10A @ 250 VAC
500mA MINIMUM @ 24 VDC
NOT INTENDED FOR
CONNECTION TO CONTROL
PANELS.
TROUBLE CONTACT RATING
0.3 A @ 32 VAC/DC
CAUTION
Figure 7. System wiring diagram for duct detectors using a UL listed control panel (see Figure 8 for wiring
of optional accessories):
Do not loop wire under terminals when wiring detectors. Break wire runs to provide system supervision of connections.
D400-64-00 6 I56-991-08R
H0240-00
24V
120
VAC
220/240
VAC
1
2 1
2
13 14
AVAILABLE POWER INPUTS
ALARM AUXILIARY CONTACTS
FOR FAN SHUTDOWN, ETC.
15
16 17
18
19 20
N.C.
C.N.O.
N.O.C.
N.C.
ALARM AUXILIARY CONTACTS SHOWN IN
STANDBY. CONTACTS TRANSFER DURING
ALARM AS INDICATED BY THE ARROWS.
ALARM INITIATION CONTACTS
TROUBLE CONTACTS CLOSED IN ALARM AND STANDBY.
CONTACTS OPEN WHILE DETECTOR HEAD OR POWER IS
REMOVED, AND DURING RESET. OPEN CONTACTS
SIGNAL TROUBLE CONDITION TO PANEL.
9
8
5
(+) ALARM SIGNAL
AUDIBLE PIEZO ALERT WITH ALARM AND
POWER (TROUBLE) LEDS. FOR STAND ALONE
APPLICATIONS ONLY. APA451 RECOMMENDED
FOR COMPLIANCE TO NFPA 90A. LOCATE IN
NORMALLY OCCUPIED AREA OF PREMISES.
DH400ACDCIHT
DUCT DETECTOR
SEE SPECIFICATIONS FOR
ADDITIONAL POWER
SUPPLY INFORMATION.
FOR WIRING OF AUXILIARY
DEVICES, REFER TO
MANUFACTURER’S
INSTALLATION INSTRUCTIONS
OR CONTACT MANUFACTURER.
TROUBLE CONTACT RATING
0.3A @ 32 VAC/DC
POWER INPUTS ACCEPT
24 VDC, 24 VAC 50-60 HZ,
120 VAC 50-60 HZ, OR
220/240 VAC 50-60 HZ
.
CONNECT POWER SOURCE
TO APPROPRIATE TERMINALS
OF EACH DETECTOR.
ALARM AUXILIARY CONTACT RATINGS
10A @ 30 VDC RESISTIV
E
10A @ 250 VA
C
500mA MINIMUM @ 24 VDC
NOT INTENDED FOR CONNECTION
TO CONTROL PANELS.
ALARM INITIATION CONTACT RATING
2.0A @ 30 VAC/DC (0.6 POWER FACTOR)
TROUBLE CONTACTS CLOSED IN STANDBY AND ALARM.
CONTACTS OPEN WHILE DETECTOR HEAD OR POWER
IS REMOVED, AND DURING RESET. OPEN CONTACTS
EXTINGUISH OPTIONAL APA451 GREEN “POWER” LED
TO INDICATE TROUBLE CONDITION.
(–) AUX POWER
(+) AUX POWER
TROUBLE
CONTACTS
APA451
N.O.
6
7
10
11
COMMON
FIELD
INSTALLED
JUMPER
POWER3
GRN.
RED
1
2 ALARM
Figure 8. Wiring diagram for duct detector systems equipped without a control panel (see Figure 8 for
wiring of additional optional accessories):
H0241-00
D400-64-00 7 I56-991-08R
Figure 9. Wiring diagrams for optional accessories (see Figure 7 for APA451 wiring diagram):
ALARM SIGNAL (+)
AUX POWER (–)
5
6
(+)
(–)
DUCT DETECTOR
DH400ACDC
PA400 (OPTIONAL)
AUDIBLE ALERT
ALARM SIGNAL (+)
AUX POWER (–
)
5
6
(+)
(–)
DUCT DETECTOR
DH400ACDC
RA400Z (OPTIONAL)
REMOTE (LED)
ANNUNCIATOR
RED
ALARM SIGNAL (+)
AUX POWER (–
)
5
6
1
2
DUCT DETECTOR
DH400ACDC
RTS451/RTS451KEY
(OPTIONAL) REMOTE
TEST STATION
R
E
D
5
3
4
3
RESET
TEST
4
FIELD
INSTALLED
JUMPER
RESET (–)
TEST (–
)
H0242-00
[5] Duct Detector Maintenance And Test Procedures
Test and maintain duct detectors as recommended in NFPA
72. The tests contained in this manual were devised to
assist maintenance personnel in verification of proper
detector operation.
Before conducting these tests, notify the proper authorities
that the smoke detection system will be temporarily out of
service. Disable the zone or system under test to prevent
unwanted alarms.
After conducting these tests, record the appropriate information in the Detector Test Log at the end of this manual.
[5.1] Smoke Entry Tests
[5.1.1] Air Flow
To verify sufficient sampling of ducted air, use a manometer to measure the differential pressure created from air
flow across the sampling tubes. The pressure should measure no less than 0.01 inches of water and no greater than
1.20 inches of water.
[6.1.2] Smoke Response
To determine if smoke is capable of entering the sensing chamber, visually identify any obstructions. Plug the
exhaust and inlet tube holes to prevent ducted air from
carrying smoke away from the detector head, then blow
smoke such as cigarette, cotton wick, or punk directly at
the head to cause an alarm. REMOVE THE PLUGS AFTER
TESTING OR THE DETECTOR WILL NOT FUNCTION
PROPERLY.
[6.2] Standby, Alarm, And Sensitivity Tests
[6.2.1] Standby And Trouble
Standby- Check for the presence of the blinking red LEDs
(blinks about every 10 seconds) through the
housing cover. If the APA451 accessory is used,
its green Power LED should be illuminated continuously.
Trouble- If the detector LEDs do not blink or if the
APA451 Power LED is not illuminated, the detector lacks power (check wiring, panel, or power
supply), the head is missing (install), or the unit
is defective (return for repair).
Test- The trouble condition can be caused intention-
ally to verify correct operation of the system.
Remove power to the unit, remove the detector head (see Figure 11), or place the M02-0401 magnet into the Reset locator, as shown in
Figure 10. These actions should cause a trouble
condition locally and at the system control
panel.
[6.1.3] Filter Replacement
The filters do not substantially affect smoke behavior even
when they are up to 90% clogged. Quarterly visual inspection is usually often enough to determine if filters should
be replace because only a high percentage of contamination affects duct detector performance.
D400-64-00 8 I56-991-08R
Figure 10. Testing detector alarm: Figure 11. Detector head removal:
TEST
LOCATOR
TEST
MAGNET
PAINTED SIDE
TOWARD HOUSING
DUCT
HOUSING
DETECTOR
HEAD
RESET
LOCATOR
TWIST
COUNTERCLOCKWISE
TO REMOVE
DUCT
HOUSING
TWIST
CLOCKWISE
TO
INSTALL
DETECTOR
HEAD
H0243-00 H0244-00
[5.2.2] Alarm Tests
[5.2.2.1] M02-04-01 Magnet Test
1. Place the painted surface of the magnet into the Test
locator molded into the side of the housing (see Figure
10).
2. The red alarm LEDs on the detector should latch on,
as should any accessories (PA400, RA400Z, RTS451,
APA451). Verify auxiliary functions (such as fan shutdown) and system control panel alarm status.
3. Place the painted surface of the magnet into the Reset
locator molded into the side of the housing (see Figure
10). This should clear the latched alarm condition at the
detector. If a system control panel is used, the panel may
also require resetting.
[5.2.2.2] RTS451/RTS451KEY Remote Test Station
The RTS451/RTS451KEY Remote Test Station facilitates test
of the alarm capability of the duct detector as indicated
in the RTS451/RTS451KEY manual. The DH400ACDCIHT
duct detector can be reset by the RTS451/RTS451KEY. If
a system control panel is used, the panel itself may also
require resetting.
To install the RTS451/RTS451KEY, connect the device as
shown in Figure 8; wire runs must be limited to 25 ohms or
less per interconnecting wire. Place the coil in the detector
housing with the arrow facing up and pointing toward the
detector as in Figure 12. Attach the coil leads to the housing terminals as shown; polarity is not important. Firmly
screw the bracket in place over the test coil.
[5.2.3] Sensitivity Tests
[5.2.3.1] MOD400R Sensitivity Test
After verification of alarm capability, use the MOD400R test
module with a voltmeter to check detector sensitivity as
described in the test module’s manual. The housing cover
must be removed to perform this test.
If test module readings indicate that the detector head is
outside of the acceptable range that is printed on the back
of the detector head, the detector head requires cleaning
per Section [7].
[6] Detector Cleaning Procedures
Notify the proper authorities that the smoke detector system is undergoing maintenance, and that the system will
be temporarily out of service. Disable the zone or system
undergoing maintenance to prevent unwanted alarms and
possible dispatch of the fire department.
[6.1] Air Filters
1. Turn off power to the system.
2. Remove and inspect the sampling tube filters.
3. If the filters are heavily coated with dirt, replace them
with new filters. If they are not heavily coated, use a
vacuum cleaner or compressed air nozzle to remove
dust, then reinstall the filters.
[6.2] Ion Heads
1. Remove the detector cover by depressing the three lock
prongs on the top of the cover and rotating the cover
counterclockwise to remove the cover and screen assembly (see Figure 14). The optional CRT400 Cover Removal
Tool makes cover removal easier.
2. Carefully pull the screen out of the cover.
D400-64-00 9 I56-991-08R
DETECTOR
HEAD
TEST COIL
Figure 12. RTS451/RTS451KEY test coil installation:
LOCK PRONG
REMOVABLE SCREEN
(P/N RS14)
REMOVABLE
COVER
FOR
CLEANING
SENSING CHAMBER
H0245-00
3. Clean the screen thoroughly with a soft brush or vacuum. Replacement screens (RS14) are available.
4. Brush or vacuum the inside of the cover. The cover may
then be blown out with clean, compressed air.
5. Vacuum the sensing chamber before using clean,
compressed air to loosen and blow out any remaining
debris.
6. Press the screen back into the cover.
7. Replace the detector cover onto the sensing chamber.
Rotate it clockwise to lock it into place.
[7.3] Reinstallation
1. Reinstall the detector in its housing.
2. Restore system power.
3. Perform Detector Check, Section [5.7].
4. Notify the proper authorities testing has been completed
and the smoke detector system is back in operation.
Figure 13. Ion head exploded view:
H0246-00
[8] Model DH400ACDCIHT Air Duct Smoke Detector Specifications
Description
HVAC air duct mounted ionization smoke detector for separately powered systems or stand alone systems. Auxiliary
alarm relay contacts provide fan contactor shutdown to prevent HVAC circulation of smoke.
Environmental Limits
Operating Temperature: +32° to +158°F (0° to +70°C)
Storage Temperature: –22° to +158°F (–30° to +70°C)
Humidity: 10% to 93% R.H. non-condensing
Air Velocity: 500 to 4000 Ft/min.
1.5 to 20.3 m/sec.
Test Features
Magnetic test switch, magnetic reset switch, MOD400R test module (optional), RTS451 Remote Test Station (optional).
Mechanical Specifications
Length: 14.5 inches 37 cm
Width: 5 inches 13 cm
Depth (installed): 4 inches 10 cm
Weight: 4 pounds 1.8 kg
Terminals
Captive universal terminal screws with sems plates accept wire sizes of 14 gauge or smaller. The screws can withstand
10 in-lbs of tightening torque without damage.
Accessories
MOD400R Sensitivity Test Module
RA400Z Remote Annunciator
RTS451/RTS451KEY Remote Test Station, test & reset switch with alarm LED
PA400 Piezo Sounder
APA451 Annunciator with piezo, alarm & power LEDs
CRT400 Cover Removal Tool
D400-64-00 10 I56-991-08R
F36-05-00 Replacement Air Filter (two per package)
M02-04-01 Replacement Test Magnet
P48-21-00 Replacement End Plug for inlet sampling tube
RS14 Replacement Screen, Ion
A2650-01 Replacement Installation Kit (mounting hardware)
DH400 OE-1 Enclosure for outdoor applications
Sampling (Inlet) Tubes
TUBE OUTSIDE DUCT WIDTH
ST-1.5 1 to 2 feet (0.3 to 0.6 m)
ST-3 2 to 4 feet (0.6 to 1.2 m)
ST-5 4 to 8 feet (1.2 to 2.4 m)
ST-10 8 to 12 feet (2.4 to 3.7 m)
Exhaust Tube Extension
A2440-00 5.75 in. (14.6 cm.) additional
Electrical Specifications
Power supply voltage: 20-29 VDC 24 VAC 50-60-Hz 120 VAC 50-60 Hz 220/240 VAC 50-60 Hz
Input capacitance: 270 µF max. 270 µF max. N/A N/A
Reset voltage: 3.0 VDC or less 2.0 VAC or less 10 VAC or less 20 VAC or less
Reset time (by power down): 0.6 sec. max. 0.6 sec. max. 0.6 sec. max. 0.6 sec. max.
Power up time: 34 sec.max. 34 sec. max. 34 sec. max. 34 sec. max.
Alarm response time: 2 to 17 sec. 2 to 17 sec. 2 to 17 sec. 2 to 17 sec.
Electrical Ratings
Power Supply Voltage 20-29 VDC 24VAC 50-60 Hz 120 VAC 50-60 Hz 220/240 VAC 50-60 Hz
CURRENT REQUIREMENTS (USING NO ACCESSORIES)*
Max. standby current 25 mA 35 mA AC avg. 20mA AC avg. 20mA AC avg.
Max. alarm current 95 mA 55 mA AC avg. 55 mA AC avg. 30 mA AC avg.
*NOTE: Accessories require extra current. Refer to accessory device manual.
CONTACT RATINGS
Alarm initiation contacts (SPST) 2.0A @ 30 VAC/DC (0.6 power factor)
Alarm auxiliary contacts (DPDT) 10A @ 30 VDC Resistive
10A @ 250 VAC
NOTE: Alarm auxiliary contacts must switch 500 mA minimum at 24 VDC. Alarm auxiliary contacts shall not be
connected to initiating circuits of control panels. Use the alarm initiation contact for this purpose.
Trouble contacts (SPST) 0.3A @ 32 VDC (resistive)
[8] DH400 OE-1 Optional Accessory
General Description
The DH400 OE-1 all-weather enclosure is specifically
Preparation
Locate the two adhesive backed gaskets packaged with the
enclosure.
designed to house and protect the System Sensor model
DH400ACDCIHT high temperature duct detector from the
elements. This enclosure provides protection in outdoor
installations against rain, sleet, and snow or in indoor
NOTE: In order to provide effective sealing, these gaskets
must be placed on the outside of the enclosure
around the two large openings.
installations against dripping water.
Remove the protective paper. Place the gaskets around the
NOTE: The DH400 OE-1 is designed solely for the use
with System Sensor model DH400ACDCIHT high
temperature duct smoke detector.
large openings, aligning the screw holes of the gaskets with
the screw holes of the enclosure. Press firmly to insure
complete adhesion.
D400-64-00 11 I56-991-08R
Mounting
Remove the front cover of the enclosure and place it against
the duct at the desired mounting location. Make sure the
four mounting holes on the enclosure rest squarely on the
duct work.
Using the enclosure as a template, mark the location of all
eight openings (the four corner holes, the two sampling
tube openings, and the two duct mounting holes) on the
duct using a pencil or a permanent marker.
Cut the two sampling tube openings using a 1-3/8″ hole
saw or hole punch. Drill the remaining six holes (0.17″
diameter) using a #21 drill bit. Using the screws provided,
secure the enclosure at the four corners.
Please refer to insert for the Limitations of Fire Alarm Systems
Three-Year Limited Warranty
System Sensor warrants its enclosed air duct smoke detector to be free
from defects in materials and workmanship under normal use and service
for a period of three years from date of manufacture. System Sensor makes
no other express warranty for this air duct smoke detector. No agent, representative, dealer, or employee of the Company has the authority to increase
or alter the obligations or limitations of this Warranty. The Company’s
obligation of this Warranty shall be limited to the repair or replacement
of any part of the air duct smoke detector which is found to be defective in materials or workmanship under normal use and service during
the three year period commencing with the date of manufacture. After
phoning System Sensor’s toll free number 800-SENSOR2 (736-7672) for
a Return Authorization number, send defective units postage prepaid to:
D400-64-00 12 I56-991-08R
© 2003 System Sensor
System Sensor, Repair Department, RA #__________, 3825 Ohio Avenue,
St. Charles, IL 60174. Please include a note describing the malfunction and
suspected cause of failure. The Company shall not be obligated to repair
or replace units which are found to be defective because of damage, unreasonable use, modifications, or alterations occurring after the date of manufacture. In no case shall the Company be liable for any consequential or
incidental damages for breach of this or any other Warranty, expressed or
implied whatsoever, even if the loss or damage is caused by the Company’s
negligence or fault. Some states do not allow the exclusion or limitation of
incidental or consequential damages, so the above limitation or exclusion
may not apply to you. This Warranty gives you specific legal rights, and
you may also have other rights which vary from state to state.
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