5
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 housing. 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).
c.
Install the inlet tube by inserting it in through the air sampling chamber as shown in Figure 3
(3). Face sampling tube holes into the air stream (Figure 4), and secure to the housing
with 8/32 screws (12).
d.
Install the outlet tube (4)
by inserting it into the upper socket of the air sampling chamber with
the scarfed end facing downstream (See Figure 4)
.
Secure the bracket to the housing with an
8/32 screw.
e.
Make sure no sampling holes extend beyond the ductway, that the stopper remains firmly in
position, and that the duct hole
is sealed around the protruding sampling tube.
Air Duct Sampling Tube Pressure Measurement
The
CERBERUS PYROTRONICS
Model PDM-3 Pressure Differential Measuring device
should be used to ensure that the sampling tube pressure differential is within the specified
limits (See
TECHNICAL DATA).
Measurements should be taken by qualified personnel in
accordance with the
PDM-3 Instructions,
P/N 315-085535.
ELECTRICAL WIRING
The Air Duct Detector Model SA-3I/-11P is interconnected and wired following the wiring diagram
in Figure 6. Each model requires a two-wire circuit of 18 AWG min thermoplastic fixture wire,
enclosed in conduit, or of 18 AWG min limited energy shielded cable, without conduit, if permitted
by local building codes.
Control of Normally Energized and De-Energized Devices
The Model
SA-3I/-11P can be wired for direct relay control of normally energized and de-
energized devices as follows (Refer to Figure 5).
a. Wire normally energized devices (fans, blowers, etc.) to the NC contacts between ter-
minals 10 and 11 or 13 and 14 in order to shut down these devices on alarm.
b. Wire normally de-energized devices (extinguishing smoke removal fan, etc.) to the
NO contacts between terminals 9 and 10 or 12 and 13 in order to activate these
devices on alarm.
NOTE:
1. All relay contacts are shown with system in the normal supervisory, no alarm, condition.
WARNING:
If the alarm relay contacts on the control board are being used to control 120 VAC operated equip-
ment, then ensure that earth ground is properly connected to the internal ground strap, using the
proper conduit lock nuts. Failure to provide proper grounding may result in fatal electrical shock.
Figure 5
Connections for Control of Normally Energized
and De-Energized Devices
