[5.3] Secure The Detector Housing To The Duct
Slide the foam gaskets over the tube bushings as shown in
Figure 3
.
Use the two 1
1
/
4
˝ long sheet metal screws to screw the detector hous-
ing to the duct.
CAUTION: Do not overtighten the screws.
Figure 3. Installation of foam gaskets over sampling
tube bushings:
SCREW HOLES FOR
ATTACHING HOUSING
TO DUCT WORK.
H0107-00
[5.4] Sampling Tube Installation for Ducts Greater
Than 1
1
⁄
2
Feet Wide
The sampling tube is identified by a series of air inlet holes on
the tube. A plastic tube is included for ducts up to 18 in width.
All other lengths must be purchased separately. Order the cor-
rect 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 two-thirds across the duct width for optimal per-
formance. 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 sam-
pling 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 orientation is acceptable, provided
that the air flows directly into the sampling tube holes as indi-
cated in
Figure 4
.
D100-68-00
2
I56-1684-007R
[4] Figure 1: Exploded View Of Duct Smoke Detector Components
FOAM
GASKETS
PLASTIC
SAMPLING TUBE
CONDUIT HOLES
DETECTOR
HOUSING
TERMINAL STRIP
DETECTOR
COVER
SAMPLING TUBE
FILTERS
PLASTIC SAMPLING TUBE
SELF-TAPPING SCREW
POWER BOARD
DETECTOR BOARD
COVER MOUNTING
SCREWS
H0401-00
H0110-00
[5] Installation Sequence
[5.1] Verify Duct Air Flow Direction And Velocity
Model DH100ACDCI detectors are designed to be used in air han-
dling systems having air velocities of 500 to 4000 feet per minute.
Be sure to check engineering specifications to ensure that the air
velocity in the duct falls within these parameters. If necessary, use
a velocity meter to check the air velocity in the duct.
[5.2] Drill The Mounting Holes
Remove the paper backing from the mounting template supplied.
Affix the template to the duct at the desired mounting location.
Make sure the template lies flat and smooth on the duct. Center
punch holes A and B. Drill the holes as indicated on the template.
[5.2.1] Sampling Tube Installation for Ducts Less
Than 1
1
⁄
2
Feet Wide (see Figure 2)
1. Remove the front cover.
2. Slide the plastic sampling tube into the housing bushing.
3. Align the holes in the bushing with the holes in the sampling
tube. Make sure there are 6 exposed holes on the plastic sam-
pling tube. Secure with the #8 self-tapping screw into the bot-
tom of the permanent tube (shown in
Figure 1
).
NOTE:
The sampling tube end cap is critical to the proper opera-
tion of the duct smoke detector. The end cap is needed to create
the proper air flow to the sensor of the duct smoke detector.
NOTE:
For ducts greater than 1
1
⁄
2
feet in width, refer to sections
[5.4.1] and [5.4.2].
Figure 2. Plastic sampling tube
connected to duct smoke detector:
