REMOVABLE HEAD COVER
CLEANABLE SCREEN
HEAD COVER
REMOVAL SLOT
VANED CHAMBER
TEST SLOT
P/N RS24 (W/O THERMAL)
(A78-1213-01)
Figure 10. Photo Head Exploded View
AIR FLOW
DIRECTION
DUCT
DETECTOR
HOUSING
DOTS INDICATE POSITION OF
SAMPLING TUBE HOLES
AIR FLOW
DIRECTION
DUCT
DETECTOR
HOUSING
INLET
TUBE
EXHAUST
TUBE
AIR FLOW
DIRECTION
INLET
TUBE
EXHAUST
TUBE
INLET
TUBE
EXHAUST
TUBE
DUCT
DETECTOR
HOUSING
AIR FLOW
DIRECTION
EXHAUST
TUBE
INLET
TUBE
DUCT
DETECTOR
HOUSING
A78-1812-01
Figure 4. Tube Mounting Configurations with Varying Air Flow Direction and Orientation of Detector Housing.
Vertical as well as Horizontal Mounting is Acceptable.
A. INSTALLATION FOR DUCTS LESS THAN 8 FEET WIDE
1.
If the inlet tube is longer than the width of the air duct, drill a 3/4-inch hole in the duct directly opposite the hole
already cut for the inlet tube.
If the inlet tube is shorter than the width of the air duct, install the end cap into the inlet tube as shown in Figure
3.
2. Slide the inlet tube into the bushing located in the center of the duct housing. Position the tube so that the arrows
point into the air flow.
3. Secure the tube flange to the housing bushing with the two #6 self-tapping screws.
4. For tubes longer than the width of the air duct, the tube should extend out of the opposite side of the duct. If there
are more than 2 holes in the section of the tube extending out of the duct, select a different tube length using Table
1. Otherwise, trim the end of the tube protruding through the duct so that 1 to 2 inches of the tube extends outside
the duct. Plug this end with the tube end plug and tape closed any holes in the protruding section of the tube. Be
sure to seal the duct when the tube protrudes.
5. Any inlet tube over 3 feet long must be supported on the opposite side of the duct detector housing.
WARNING: There must be a minimum of 10 holes in the tube exposed to the air stream.
B. INSTALLATION FOR DUCTS MORE THAN 8 FEET WIDE
NOTE: To install inlet tubes in ducts more than 8 feet wide, work must be performed inside the air duct. Sampling of
air in ducts wider than 8 feet is accomplished by using the ST-10 inlet sampling tube.
Install the inlet tube as follows:
1. Drill a 3/4-inch hole in the duct directly opposite the hole already drilled for the inlet tube.
2. Slide the inlet tube into the bushing located in the center of the duct housing. Position the tube so that the arrows
point into the air flow. Secure the tube flange to the housing bushing with the two #6 self-tapping screws.
3. From inside the duct, couple the other section of the inlet tube to the section already installed using the 1/2-inch
conduit fitting supplied. Make sure that the holes on both of the air inlet tubes are lined up facing the direction of
air flow.
4. Trim the end of the tube protruding through the duct so that 1 to 2 inches of the tube extends outside the duct. Plug
this end with the tube end plug and tape closed any holes in the protruding section of the tube. Be sure to seal the
duct when the tube protrudes.
5. Any tube (over 3 feet long) that does not protrude through the duct (on the side opposite the housing) must be
supported by other means.
NOTE: An alternate method to using the ST-10 is to use two ST-5 inlet tubes. Remove the flange from one of the tubes
and install as described above. After the installation, use electrician’s tape to close off some of the sampling
holes so that there is a total of 12 holes spaced as evenly as possible across the width of the duct.
of this manual.
Recommended Detector Maintenance Procedure
NOTE: Notify the proper authorities that the smoke detector
system is undergoing maintenance, and therefore
the system will be temporarily out of service. Disable
the zone or system undergoing maintenance to pre-
vent unwanted alarms and possible dispatch of the
fire department.
1. Turn off power to the system.
2. Remove and inspect the sampling tube filters.
3. If filters are heavily coated with dirt, replace them with
new filters. If they are not heavily coated, use a vacuum
cleaner or compressed air nozzle to remove dust, then
install the filters.
4. Remove the detector from its housing. (See Figure 8.)
PHOTO UNITS
5. Remove the detector cover by inserting a small-bladed
screwdriver into the slot located approximately 90 de-
grees from the MOD400R test jack receptacle, rotating
the cover counterclockwise to remove it (see Figure 10.)
6. Lift the screen from the photo chamber. Vacuum the
screen and cover before using clean, compressed air to
loosen and blow out any remaining debris. (Replacement
screens, part no. RS24, are available.)
7. Vacuum the photo chamber before using clean com-
7. Replace the cover by gently rotating it clockwise until it locks in place. Secure the duct housing cover.
7.3 MOD400R SENSITIVITY TEST
After verification of alarm capability, use the MOD400R test module with a voltmeter to check detector sensitivity as
described in the MOD400R manual. The housing cover must be removed to perform this test.
If the MOD400R readings indicate that the sensor head is outside of the acceptable range, the sensor heads require
cleaning. (Refer to PERIODIC MAINTENANCE REQUIREMENTS).
7.4 TROUBLE TEST
The capability of Trouble detection is tested by removing the detector head from the duct housing. The detector head
is removed by turning it counterclockwise about 10 degrees (Figure 8). The system control panel should indicate a
trouble condition. Replacing the detector head should clear the trouble indication.
STEP 8. INSTALL THE COVER
Install the cover using the four screws. Be certain filters are installed as specified in Step 6. Make sure that the cover
fits into the base groove and that all gaskets are in their proper positions. Tighten the four cover screws to 10 in-lbs.
STEP 9. PERFORM THE FINAL SYSTEM CHECK
Place the magnet in position as shown in Figure 7. The LEDs on the detector should light. Any accessory LED(s)
should also light. The system control panel should also indicate an alarm.
PERIODIC MAINTENANCE REQUIREMENTS
Air duct smoke detectors should be maintained at least once a year – more often if the detector heads become
obviously dirty. The detectors must also be cleaned immediately after a fire. Failure to properly maintain air duct
smoke detectors may cause unnecessary false alarms.
It is recommended that a permanent Detector Test Log be set up and maintained, with a record for each individual
smoke detector in each building. Each detector should be clearly described, with information on the type of detector,
the model number, the serial number (if any), the location, and the type of environment. Data entries should include
test dates, type of test mode, test results, maintenance, and comments. A Detector Test Log is included at the end
N500-03-00
4
I56-456-07
N500-03-00
9
I56-456-07