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P/N 315-049708FA-4

4

2) To minimize the impact of air turbulence and stratification

on performance, a duct smoke detector should be
located as far as possible downstream from any obstruc-
tion (i.e. deflector plates, elbows, dampers, etc.). In all
situations, confirmation of velocity and pressure differen-
tial within specifications is required.
The pressure differential between the input sampling
(high pressure) tube and outlet (low pressure) tube for
the 8741, 8742 or 8743 duct smoke detector should be
greater than 0.01 inches of water and less than 1.2
inches of water.

3) Identify a code compliant location (supply or return side,

or both) for the installation of the duct unit that will
permit easy access for viewing and serviceability.

4) When installing on the return side, install duct units prior

to the air being exhausted from the building or diluted
with outside “fresh” air.

5) When installing duct smoke units downstream of filters,

fires occurring in the filters will be detected, but if the
filters become blocked, insufficient air flow through the
duct unit will prevent the correct operation of the duct
detector. Duct units installed in the supply air side may
monitor upstream equipment and/or filters.

6) Where possible, install duct detectors upstream of air

humidifiers and downstream of dehumidifiers.

7) To prevent false alarms, the duct detector should not be

mounted in areas of extreme high or low temperatures,
in areas where high humidity exists, or in areas where
the duct may contain gases or excessive dust.

Duct Preparation

The 8741, 8742 and 8743 Housings come with an installation
kit that contains the following items:

• Short return (outlet) sampling tube
• Stopper
• Two #12 x 

3

/

4

” sheet metal screws

• Mounting template (packaged separately)

Remove mounting template from the installation kit. Remove
paper backing from the mounting template and affix it to the
duct at the desired location. Using the template as a guide,
drill (2) mounting holes, 3/32" (2.5mm) for the #12 X 

3

/

4

sheet metal screws packaged in the installation kit. Drill or

Содержание 8742

Страница 1: ...c see char har har har harts on the page ts on the page ts on the page ts on the page ts on the page 1 1 1 1 12 of this manual 2 of this manual 2 of this manual 2 of this manual 2 of this manual TECHN...

Страница 2: ...detector is equipped with cover removal switch SW1 that instantly provides a trouble condition upon removal of the clear cover For all testing and inspection with the cover removed the cover removal...

Страница 3: ...R PLENUM FRESH AIR INTAKE DAMPER D D Figure 1 Typical Mounting of Duct Housing OUTLET TUBE INPUT SAMPLING TUBE CENTER LINE OF DUCT C L MOUNTINGTHE AIR DUCT HOUSING Location on Duct System This guideli...

Страница 4: ...m of filters fires occurring in the filters will be detected but if the filters become blocked insufficient air flow through the duct unit will prevent the correct operation of the duct detector Duct...

Страница 5: ...be cut to length and must span at least 80 the width of the duct Sampling tubes over 3 0 must be supported on the opposite side of the duct To ensure the correct operation the red stopper stopper in i...

Страница 6: ...d the duct unit assembly in position and use 2 12 X 3 4 sheet metal screws packaged in the installation kit to secure the duct smoke detector to the HVAC duct sheet metal Air Duct Sampling Tube Pressu...

Страница 7: ...e loop Note any limitations on the number of detectors and restrictions on the use of remote devices permitted for each circuit When replacing a detector with a different model be aware that existing...

Страница 8: ...the initiating circuit 3 Do not use looped wire under base terminal 4 Break wire run to provide supervision of connection 5 The green grounding screw in the wiring compartment of the air duct housing...

Страница 9: ...6 or 5 TB3 5 or 6 TB1 1A TB1 TB1 TB1 MODEL 8741 MODEL 8743 MODEL 8743 8710 8713 OPTIONAL REMOTE ALARM INDICATOR MODEL 8727C OR 8727W SEE NOTE 2 LOOP WIRES SEE COMPATIBLE CONTROL EQUIPMENT TABLE 8710 8...

Страница 10: ...zle model AD TGN purchased separately available from Siemens Industry Inc insert the test gas nozzle into the hole in the red test plug in the unit cover Press can against cover for about 1 2 second t...

Страница 11: ...F ed Farada arada arada arada araday S y S y S y S y Service R ervice R ervice R ervice R ervice Represent epresent epresent epresent epresentat at at at ati i i i ive ve ve ve ve If the fire alarm sy...

Страница 12: ...P M 0 0 0 6 C P M 5 A F 0 5 8 4 3 0 5 1 3 N P 1 0 4 W L 3 A F 7 9 9 5 9 0 5 1 3 N P 1 0 4 W L A 4 E Z W L 4 A F 8 1 0 6 9 0 5 1 3 N P 1 0 4 W L A 8 E Z W L 3 A F 2 2 0 6 9 0 5 1 3 N P R O T C E T E D...

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