For signal wiring, (the wiring between interconnected de-
tectors or from detectors to auxiliary devices), it is usually
recommended that single conductor wire be no smaller
than 18 gauge. The duct smoke detector terminals accom-
modate wire sizes up to 12 gauge. The last foot of conduit
should be flexible conduit (available in electrical supply
houses), which facilitates easier installation and puts less
strain on the conduit holes in the housing. Solid conduit
connections may be used if desired.
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 DH100 detectors are 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 un-
der the plate, and tightening the clamping plate screw.
The DH100 duct smoke detector is designed to operate with
12 or 24 VDC UL listed 2-wire compatible control panels.
Alarm current must be limited by the control panel to
100mA or less. An example of a UL listed compatible con-
trol panel is the Fire-Lite model Sensiscan 1000 using zone
card ANC-2 and compatibility identification “A”. Install per
installation instruction S1000/801. A maximum of 20 detec-
tors may be installed per zone.
[5.7] Perform Detector Check
1. Perform STANDBY AND TROUBLE TEST per Section
[6.2.1].
2. Perform MAGNET TEST per Section [6.2.2.1]. The
RTS451 test of Section [6.2.2.2] may substitute for this
requirement.
3. Perform AIR FLOW TEST per Section [6.1.1].
4. Perform SMOKE RESPONSE TEST per Section [6.1.2].
5. Perform SENSITIVITY TEST per Section [6.2.3].
[5.8] Install The Cover
Install the cover using the four screws that are captured in
the housing cover. Be certain filters are installed as speci-
fied in Section [5.5]. Make sure that the cover fits into the
base groove and that all gaskets are in their proper posi-
tions. Tighten the four screws.
[6] Duct Smoke Detector Maintenance And Test
Procedures
Test and maintain duct smoke detectors as recommended in NFPA
72. The tests contained in this manual were devised to assist main-
tenance 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.
[6.1] Smoke Entry Tests
[6.1.1] 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 0.03 inches of water and no greater than 1.4 inches
of water. The air handler must be operating for this test.
[6.1.2] Smoke Response
To determine if smoke is capable of entering the sensing
chamber, visually identify any obstructions. Plug the ex-
haust and inlet tube holes to prevent ducted air from carry-
ing smoke away from the detector head, then blow smoke
such as cigarette, cotton wick, or punk directly at the head
to cause an alarm. REMEMBER TO REMOVE THE PLUGS
AFTER THIS TEST, OR THE DETECTOR WILL NOT FUNC-
TION PROPERLY.
[6.1.3] Filter Replacement
The filters do not substantially affect smoke performance
even when up to 90% of the filter is clogged. Quarterly vi-
sual inspection usually suffices to determine whether the
filters should be replaced because only a high percentage of
contamination affects performance. If further testing is re-
quired, compare differential pressure readings with and
without the filters installed. If the difference exceeds 10%
replace the filters. In no case should the pressure differen-
tial fall below 0.03 inches of water.
[6.2] Standby, Alarm, And Sensitivity Tests
[6.2.1] Standby And Trouble
Standby —
Look for the presence of the flashing green
LED through the transparent housing cover.
The LED should flash approximately every 10
seconds.
Trouble —
If the Green LED does not flash, then the de-
tector lacks power (check wiring, panel, or
power supply), the detector board is missing
(replace), or the unit is defective (return for
repair)
Test —
The trouble condition can be caused inten-
tionally to verify correct operation of the sys-
tem. Remove the detector board to cause a
trouble condition locally and at the system
control panel.
D100-67-00
5
I56-1148-04
