[5.4.3] Modifications of Sampling Tubes
There may be applications where duct widths are not what is
specified for the installation. In such cases, it is permissible to
modify a sampling tube that is longer than necessary to span the
duct width.
Use a 0.193-inch diameter (#10) drill and add the appropriate num-
ber 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 pos-
sible over the length of the tube.
NOTE:
This procedure should only be used as a temporary fix. It
is not intended as a permanent substitute for ordering the correct
length tubes.
[5.4.4] Alternate Method of Sampling Tube Installation
The detector arrangement can also incorporate the remote mount-
ing of the sampling tube and/or exhaust tube. In this case both
the detector, sampling tube and exhaust tube (if included) should
be rigidly mounted to withstand the pressure and resonant vibra-
tions caused by the air velocity. The location of the detector’s
sampling tube should be such that there is uniform airflow in the
cross section area.
An air tight connection shall be made between the sampling tube,
exhaust tube and their corresponding ports on the detector hous-
ing. Upon selection of location in the system, pressure differential
across the sampling and exhaust ports in the detector housing
shall be verified to be within the allowable range of the detec-
tor. This is accomplished by measuring the pressure difference
between the inlet and outlet ports on the detector housing using a
manometer as described in Section 6 of this manual.
[5.5] Install The Filters
To install the sampling tube filters, simply push the filters into the
sampling and exhaust tube holes, as shown in Figure 6. If a metal
sampling tube is used, install the filters over the tube ends.
Figure 6. Sampling tube filter installation:
H0159-00
CAUTION
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 F36-09-11)
[5.6] Field Wiring
Installation Guidelines
All wiring must be installed in compliance with the National Elec-
trical 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 prevent wiring mistakes. Improper connections can pre-
vent 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
smoke detector terminals accommodate wire sizes up to 12 gauge.
Smoke detectors and alarm system control panels have specifi-
cations 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 DH100ACDCLP detectors are designed for easy wiring. The
housing provides a terminal strip with clamping plates. Wiring
connections are made by stripping about 3/8” of insulation from
the end of the wire, sliding the bare end under the plate, and
tightening the clamping plate screw.
[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 six screws that are captured in the hous-
ing cover. Be certain filters are installed as specified in Section
[5.5]. Make sure that the cover fits into the base groove and that
all gaskets are in their proper positions. Tighten the six 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. Dis-
able the zone or system under test to prevent unwanted alarms.
[6.1] Smoke Entry Tests
[6.1.1] Air Flow
The DH100ACDCLP is designed to operate over an extended air speed
range of 100 to 4000 FPM. To verify sufficient sampling of ducted air,
turn the air handler on and use a manometer to measure the dif-
ferential pressure between the two sampling tubes. The differential
pressure should measure at least 0.0015 inches of water and no more
than 1.2 inches of water. Because most commercially available ma-
nometers cannot accurately measure very low pressure differentials,
applications with less than 500 FPM of duct air speed may require
one of the following: 1) the use of a current-sourcing pressure trans-
mitter (Dwyer Series 607) per Section 6.1.4 or; 2) the use of aerosol
smoke per section 6.1.2.
[6.1.2] Air Flow Test using Aerosol Smoke
This test is intended for low-flow systems (100-500 FPM). If the
air speed is greater than 500 FPM, use a conventional manometer
to measure differential pressure between the sampling tubes, as
described in 6.1.1.
Drill a
1
⁄
4
˝ hole 3 feet upstream from the duct smoke detector. With
the air handler on, measure the air velocity with an anemometer.
Air speed must be at least 100 FPM. Spray aerosol smoke* into
the duct through the
1
⁄
4
˝ hole for five seconds. Wait two minutes
for the duct smoke detector to alarm. If the duct smoke detec-
D200-14-00
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I56-0084-009R
