Conventional Products—DH400 Conventional Air Duct Smoke Detector 13
5.
Secure the tube flange to the housing bushing with two No. 6
self-tapping screws.
6.
For tubes longer than the width of the air duct:
The tube should extend out of the opposite side of the duct.
7.
If there are more than two holes in the section of the tube extending
out of the duct:
Select a different length (Table 4).
8.
Otherwise, trim the end of the tube protruding through the duct so that
one to two inches of the tube extend outside the duct.
9.
Plug this end with the end plug.
10. Tape close any holes in the protruding section of the tube.
11. Be sure to seal the duct when the tube protrudes.
Note: In no case should more than two air inlet holes be cut off the tube.
There must be a minimum of ten holes in the tube exposed to the
air stream.
To install inlet tubes in ducts more than eight feet wide, work must be
performed inside the air duct. Sampling of air in ducts wider than eight
feet is accomplished by using the ST-10 inlet sampling tube. If the tube is
shorter than the width of the air duct, install the end plug into the inlet
tube, and support the end opposite the duct detector (Figure 5).
To install the inlet tube:
1.
Drill a 3/4 inch hole in the duct directly opposite the hole already
drilled for the inlet tube.
2.
Slide the inlet tube with the flange into the centermost housing
bushing.
3.
Position the tube so that the arrows point into the airflow.
4.
Secure the tube flange to the housing bushing with two No. 6
self-tapping screws.
5.
From inside the duct, couple the other section of the inlet tube to the
section already installed using the 1/2 inch conduit fitting supplied.
6.
Make sure that the holes on both of the air inlet tubes are lined up and
face into the airflow.
7.
Trim the end of the tube protruding through the duct so that
one to two inches of the tube extend outside the duct.
8.
Plug this end with the end plug.
9.
Tape close any holes in the protruding section of the tube.
10. Be sure to seal the duct when the tube protrudes.
Installation for
Ducts More Than
Eight Feet Wide
