F300-28-00
4
I56-1974-006R
[4.2] Installation For Ducts More Than 8 Feet (2.4m) Wide
NOTE:
To install sampling tubes in ducts more than 8 feet (2.4m) wide, work must be performed inside the air duct. Sampling of air in
ducts wider than 8 feet (2.4m) is accomplished by using the ST-10 sampling tube. If the tube is shorter than the width of the air duct,
install the end cap into the sampling tube as shown in Figure 4 and support the end opposite the duct smoke detector.
Install the sampling tube as follows:
1. Drill a
3
⁄
4
˝ (19mm) hole in the duct directly opposite the hole already drilled for the sampling tube. Make sure the hole is 1˝ to 2˝
(25 to 50mm) below the inlet hole on the opposite side of the duct to allow for moisture drainage.
2. Slide the sampling tube with the flange into the housing bushing that meets the air flow first. Position the tube so that the arrow
points 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 sections of the sampling tube to the section already installed using the
1
⁄
2
˝ conduit fittings
supplied. Make sure that the holes on both of the sampling 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˝ (25 to 50mm) of the tube extend outside the duct. Plug this end
with the end cap and tape closed any holes in the protruding section of the tube. Be sure to seal the duct where the tube protrudes.
NOTE:
An alternate method to using the ST-10 is to use two ST-5 sampling 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 are a total of 10 to
12 holes spaced as evenly as possible across the width of the duct.
NOTE:
Air currents inside the duct may cause excessive vibration, especially when the longer sampling tubes are used. In these cases
a 3˝ (75mm) 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˝ to 1
1
⁄
4
˝ (25 to 32mm) hole where the flange will be used.
[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 end.
[6] Field 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
prevent wiring mistakes. Improper connections can prevent a system from responding properly in the event of a fire.
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 [9.1.2] for more information. Replacement
filters can be ordered (filter P/N F36-09-11).
For signal wiring, (the wiring between detectors or from detectors to auxiliary devices), it is usually recommended that single conduc-
tor wire be no smaller than 18 gauge. The duct smoke detector terminals accommodate 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 Signaling-Line Circuit (SLC) wiring. Consult the control panel
manufacturer’s specifications for wiring requirements for the particular model control panel being used before wiring the detector loop.
The D350RPL detector is designed for ease of wiring. The housing provides a terminal strip with clamping plates.
Wiring connections are made by stripping about
3
⁄
8
˝ (9mm) of insulation from the end of the wire, sliding the bare end under the plate,
and tightening the clamping plate screw.
Two LEDs on each duct smoke detector may light, if pro-
grammed by the system control panel, to provide a local,
visible indication. Remote LED annunciator capability is
available as an option. Each duct smoke detector can only be
wired to one remote accessory.
Figure 6. Sampling tube filter installation:
H0138-00
