7
Trimming the Inlet Sampling Tube (See Figure 4)
a. Measure the outside width of the duct.
b. Add 2.25 inches to obtain proper length of tube.
Example: Outside width of duct
2 ft 6 in
Add 2.25 inches
+ 2.25 in
Length of sampling tube
2 ft 8.25 in
The length (2 ft 8.25 in) determines (Table 5 on page 5) the
model number of the appropriate sampling tube (STA-3).
c. Measure the sampling tube, starting from the end with the four mount-
ing holes.
d. Trim tube to the correct length, remove all burrs, and insert a rubber
stopper (Figure 3, Item 9) in the tube.
Installation of the Sampling Tubes
a. Before installing the tubes, cut a
7
/
8
-inch hole in the duct wall that is
directly opposite the inlet sampling chamber hole in the detector hous-
ing. This will allow the inlet tube to protrude through the duct.
b. Attach brackets (10) to the inlet and outlet air sampling tubes with
3
/
16
screws (11).
NOTE: When attaching brackets, be sure to align tubes properly
(See Figure 4).
Figure 4
Sampling Tube Orientation
