Figure 2. Speed nut mounting location:
HOLE B
HOLE A
DUCT
WALL
SPEED
NUT 
CAUTION: Do not overtighten the screws.
Exception: Where it is physically impossible to locate the detector accordingly, the detector can be positioned closer than six duct widths, but as far as possible from the open- ing, bend, or deflection plates.
Step 3. Mount Duct Housing
Remove the duct housing cover. Slide the foam gaskets over the tube bushings as shown in Figure 2A. Make sure the two small holes in the gaskets line up with the two duct housing mounting holes. Put one
Table 1. Sampling (Inlet) Tubes |
| |
TUBE | OUTSIDE DUCT WIDTH | |
1 to 2 ft. | (0.3 to 0.6 m) | |
2 to 4 ft. | (0.6 to 1.2 m) | |
4 to 8 ft. | (1.2 to 2.4 m) | |
8 to 12 ft. | (2.4 to 3.7 m) | |
Figure 3. Air duct detector inlet sampling tube:
Figure 2A. Installation of foam gaskets over sam- pling tube bushings:
MOUNTING | SAMPLING | DUCT DETECTOR |
TUBE BUSHING | HOUSING | |
SCREWS |
|
|
| EXHAUST TUBE | |
|
| (EXTENSION BUSHING) |
|
| FOAM |
|
| GASKETS |
SCREW HOLES FOR ATTACHING
DETECTOR HOUSING TO DUCT
Step 4. Install The Inlet Tube
The inlet tube (shown in Figure 3) is identified by a series of air inlet holes on the tube. This tube must be purchased separately. Order the correct length, as specified in Table 1, for the width of the duct where it will be installed. The exhaust tube is molded into the base of the duct housing.
The inlet tube should be installed in the inlet sampling tube bushing located in the center of the duct detector housing. (See Figure 2A.) The air inlet holes must face into the air flow. To assure proper installation, the tube mount- ing flange is marked with arrows. Mount the inlet tube so that the arrows point into the air flow. Figure 4 shows the various combinations of duct detector and tube mounting configurations with respect to air flow.
FLANGE | AIR HOLES | INLET |
| ||
|
| TUBE |
|
| END |
|
| PLUG |
ARROWS | AIR FLOW DIRECTION | |
MUST FACE |
|
|
INTO AIR FLOW
3 |
