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Fig. 38 —
Typical Supply Air Smoke Detector Sensor
Location
RETURN AIR SMOKE DETECTOR SENSOR WITHOUT
ECONOMIZER
The sampling tube is located across the return air opening on
the unit basepan. See Fig. 39. The holes in the sampling tube
face downward, into the return air stream. The sampling tube is
connected through tubing to the return air sensor that is mount
-
ed on a bracket high on the partition between return filter and
controller location. The sensor is shipped in a flat-mounting lo
-
cation. Installation requires that this sensor be relocated to its
operating location and the tubing to the sampling tube be con
-
nected. See installation steps.
RETURN AIR SMOKE DETECTOR SENSOR WITH
ECONOMIZER
The sampling tube is inserted through the side plates of the econo
-
mizer housing, placing it across the return air opening on the unit
basepan. See Fig. 40. The holes in the sampling tube face down
-
ward, into the return air stream. The sampling tube is connected
using tubing to the return air sensor mounted on a bracket high on
the partition between return filter and controller location. The sen
-
sor is shipped in a flat-mounting location. Installation requires the
sensor be relocated to its operating location and the tubing to the
sampling tube be connected. See installation steps below.
Completing Installation of Return Air Smoke
Detector
Use the following steps to complete the installation of the
return air smoke detector.
1. Unscrew the two screws holding the return air sensor
detector plate. See Fig. 41. Save the screws.
2. Remove the return air smoke sensor module and its
detector plate.
3. Rotate the detector plate so the sensor is facing outwards and
the sampling tube connection is on the bottom. See Fig. 42.
4. Screw the sensor and detector plate into its operating position
using screws from Step 1. Ensure the sampling tube connec
-
tion is on the bottom and the exhaust tube is on the top.
5. Connect the flexible tube on the sampling inlet to the sam
-
pling tube on the basepan.
6. For units with an economizer, the sampling tube is inte
-
grated into the economizer housing but connecting the
flexible tubing to the sampling tube is the same.
Fig. 39 —
Typical Return Air Smoke Detector Location
Fig. 40 —
Return Air Sampling Tube Location (View
reoriented to show opposite side for clarity.)
Fig. 41 —
Return Air Smoke Detector Shipping Position
SUPPLY AIR
SMOKE DETECTOR
RETURN AIR
SMOKE DETECTOR
(AS SHIPPED)
RETURN AIR
SAMPLING TUBE
SAMPLE TUBE
SCREWS
FLEXIBLE EXHAUST TUBES