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INST APD0344 A090630
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INST APD0344 A090630
LOCATiON PReReqUiSiTeS
This guideline contains general information on
duct smoke detector installation, but does not
preclude the NFPA and/or ICC documents listed
on page 1. Air Products and Controls assumes
no responsibility for improperly installed
duct detectors. To determine the correct
installation position for an RT-3000 Series duct
smoke detector, the following factors must be
considered:
1) A uniform non-turbulent (laminar) airflow
between 100 ft/min. to 4,000 ft/min. must
be present in the HVAC duct. To determine
duct velocities, examine the engineering
specifications that define the expected velocities
or use an Alnor model 6000AP velocity meter
(or equivalent).
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 obstruction (i.e. deflector
plates, elbows, dampers, etc.). In all situations,
confirmation of velocity and pressure differential
within specifications is required.
The pressure differential between the input
sampling (high pressure) tube and exhaust (low
pressure) tube for the RT-3000 Series smoke
duct detector should be greater than 0.01
inches of water and less than 1.8 inches of water.
See page 4 for detailed information on pressure
differential gauges.
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.
SAMPLiNG TUBe ASSeMBLy
The RT-3000 Series duct smoke detectors
employ a specially notched sampling tube, which
must be ordered separately in one of four
standard lengths.
STN-1.0
For duct widths of 6" to 1.0'
STN-2.5
For duct widths of 1.0' to 3.0'
STN-5.0
For duct widths of 3.0' to 5.0'
STN-10.0
For duct widths of 5.0' to 10.0'
Standard sampling tubes are steel tubes with
air intake holes punched the entire length of
the tube. These tubes can 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. For custom duct
widths, always use the next longest standard size
and cut down to the exact requirement.
To ensure the correct operation of the exhaust
tube, the red end cap (red stopper in installation
kit) must be inserted in the end of the air intake
sampling tube.
NO-TOOLS
TUBe iNSTALLATiON
The RT-3000 Series duct smoke detector
provides a unique, patented mechanism for
installation and/or removal of the sampling and
exhaust tubes from either the front or rear of
the detector housing.
Once the airflow direction has been determined,
insert the inlet and exhaust tubes into the duct
smoke detector. If the cover is in place, the tubes
may be inserted into the back of the detector
via the key-slots provided. Simply push the tube
into place against the spring loaded retainer, and
turn to the correct position, allowing the key to
MeCHANiCAL iNSTALLATiON
“lock” the tube in the desired orientation.
For front side installation, simply rotate the tube
retainer so that the tube may be inserted and
oriented properly. Once the tube is installed,
rotate the retainer back into place to lock
down the tube. Ensure air intake sampling tube
is positioned so that the inlet holes are directly
facing the airflow (the air sampling holes are
aligned with the notch in the tube).
DUCT PRePARATiON
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 ½"
sheet metal screws packaged in the installation kit. Drill or punch (2) 1¼" (32mm) holes for inlet
sampling and exhaust tubes, using the template as a guide. Clean all holes.
MOUNTiNG
To maintain the Type 4X watertight, corrosion resistant properties of this duct smoke detector, and
in accordance with NFPA 70 / the National Electric Code, Listed watertight (outdoor) conduit and
fittings must be used. Preferably, mount the product with the conduit holes facing downwards. If
vertical mounting is required based on the application, simply orient the sampling tube so it is on the
upstream side of the exhaust tube.
After securing the sampling and exhaust tubes to the duct smoke unit, (or initially placing the tubes
through the 1¼" holes drilled or punched in the HVAC duct to accept the inlet sampling and
exhaust tubes and then attaching them to the duct unit), hold the duct unit assembly in position and
use (2) # 12 X ½" sheet metal screws (packaged in the installation kit) to secure the duct smoke
detector to the HVAC duct sheet metal.
AiR SAMPLiNG veRiFiCATiON
To ensure correct operation of the duct unit use a Magnehelic differential pressure gauge, Dwyer
2000 or 4000 Series (or equivalent) to determine the differential pressure between the inlet (high
side) and exhaust (low side) tubes. The differential pressure between the two tubes should be
greater than 0.01 inches of water and less than 1.8 inches of water.
This duct smoke detector is shipped with a velocity adapter insert, either factory installed
(RT-3000-P), or found in the installation kit (RT-3000-N). When installed, this adapter will allow
the duct detector to operate at extremely low air velocities. To install the adapter, simply insert it
into the slots provided inside the detector housing so that the adapter fits snugly over the smoke
detector head. Unless your system is consistently operating in the slower velocity range (where
the adapter is specifically required, RT-3000-N), we recommend that the adapter not be inserted.
If you experience false alarms at higher velocities with the adapter in place, the adapter should be
removed. Please use the following chart for guidance on when the velocity adapter should be used.
For reference, the speeds indicated are intended to represent the velocity of air within the duct
under normal operational conditions.
100 ft/min
300 ft/min
500 ft/min
1,000 ft/min 2,000 ft/min
3.000 ft/min
4,000 ft/min
RT-3000-N
UL Listed
without
insert installed (500-4,000 ft/min)
UL Listed
with
insert installed (100-4,000 ft/min)
RT-3000-P
UL Listed
without
insert installed (500-4,000 ft/min)
UL Listed
with
insert installed (100-4,000 ft/min)
INLET TUBE
HOLES FACE
AIR FLOW
DUCT WIDTH
AIR FLOW DIRECTION
INSERT RED STOPPER
THIS END OF INLET TUBE
EXHAUST TUBE INSTALLED
DOWNSTREAM OF AIRFLOW
DO NOT INSERT RED STOPPER
NOTE: Mountings shown
are typical. Detectors can
be installed side, bottom
or top of duct as long as
proper tube operation and
flow/pressure performance
is maintained
Tube Support Hole only for Ducts Greater than 3 Feet Wide
