System Sensor DH100LP - Manual (Page 3)

Be sure to seal the duct when the tube protrudes.
NOTE: The sampling tube end cap is critical to the
proper operation of the duct smoke detector. The end
cap is needed to create the proper air flow to the sensor
of the duct smoke detector.
Figure 4. Air duct detector inlet sampling tube:
SAMPLING
TUBE
END CAP
AIR HOLES
ARROW
MUST FACE
INTO AIR FLOW
AIR FLOW DIRECTION
FLANGE
H0108-02
Figure 5. Tube mounting configurations with varying
air flow direction:
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
NOTE: Only metal sampling tubes may be used on orien-
tations C and D.
WARNING
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 ex-
posed to the air stream.
[5.4.2] Installation For Ducts More Than 8 Feet Wide
NOTE: To install sampling tubes in ducts more than 8 feet
wide, work must be performed inside the air duct. Sam-
pling of air in ducts wider than 8 feet 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 sam-
pling tube as shown in Figure 4 and support the end op-
posite the duct smoke detector.
Install the sampling tube as follows:
1. Drill a
3 ⁄
4
˝ hole in the duct opposite the hole already
drilled for the sampling tube. Drill the hole 1˝ to 2˝ be-
low the inlet hole on the opposite side of the duct to
allow for moisture drainage away from the detector.
2. Slide the sampling tube with the flange into the hous-
ing bushing that meets the air flow first. Position the
[5.4] Sampling Tube Installation of Ducts Greater
Than 1
1 ⁄
2
Feet Wide
The sampling tube is identified by a series of air inlet holes
on the tube. One plastic tube is included for ducts up to 18˝
in width. All other lengths must be purchased separately.
Order the correct length, as specified in Table 1, for width
of the duct where it will be installed. It is recommended
that the sampling tube length extend at least
2 ⁄
3
˝ across the
duct width for optimal performance. The exhaust tube is
molded onto 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.
The sampling tube is always installed with the air inlet
holes facing into the air flow. To assist proper installation,
the tube’s mounting flange is marked with an arrow. Make
sure the sampling tube is mounted so that the arrow points
into the air flow (see Figure 4). Figure 5 shows the various
combinations of tube mounting configurations with respect
to air flow. Mounting the detector housing in a vertical ori-
entation is acceptable, provided that the air flows directly
into the sampling tube holes as indicated in Figure 4.
Table 1. Sampling tubes recommended for different
duct widths:
Outside Duct Width Sampling Tube Recommended*
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
*Must extend a minimum of 2 ⁄
3
the duct width
[5.4.1] Installation For Ducts Greater Than 1 1 ⁄
2
Feet
But Less Than 8 Feet Wide
1. If the tube is longer than the width of the air duct, drill a
3 ⁄
4
˝ hole in the duct opposite the hole already cut for the
sampling tube. Make sure the hole is 1˝ to 2˝ below the
inlet hole on the opposite side of the duct to allow for
moisture drainage. 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. Sampling tubes over 3 ft. long must
be supported at the end opposite the duct detector.
2. Slide the tube into the housing bushing that meets the
air flow first. Position the tube so that the arrow points
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˝ of the tube extend out-
side the duct. Plug this end with the end cap and tape
closed any holes in the protruding section of the tube.
D200-15-00 3 I56-0083-009R
H0109-01