System Sensor DH100LP - Manual (Page 4)

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 Fig-
ure 6. If a metal sampling tube is used, install the filter
over the sampling tube.
Figure 6. Sampling tube filter installation:
WARNING
Filters require periodic cleaning or replacement, depending
on the amount of dust and dirt accumulated. Visually in-
spect 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. (Ex-
haust tube/intake tube filter P/N F36-09-11)
[5.6] Field Wiring Installation Guidelines
All wiring must be installed in compliance with the Na-
tional Electrical Code and the local codes having jurisdic-
tion. Proper wire gauges should be used. The conductors
used to connect smoke detectors to control panels and ac-
cessory devices should be color-coded to prevent wiring
mistakes. Improper connections can prevent a system from
responding properly in the event of a fire.
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 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 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.
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 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˝ 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 when 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 inch floor flange (available at most
plumbing supply stores) may be used to fasten the sam-
pling tube to the other side of the duct. When using the
flange/connector mounting technique, drill a 1 to 1
1 ⁄
4
˝ hole
where the flange will be used.
[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 permis-
sible to modify a sampling tube that is longer than neces-
sary to span the duct width.
Use a 0.193-inch diameter (#10) 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.
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
mounting 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 pres-
sure and resonant vibrations 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 sam-
pling tube, exhaust tube and their corresponding ports on
the detector housing. Upon selection of location in the sys-
tem, pressure differential across the sampling and exhaust
ports in the detector housing shall be verified to be within
the allowable range of the detector. This is accomplished
D200-15-00 4 I56-0083-009R
H0138-00