SM-501-N 4-Wire, Ionization Type
SM-501-P 4-Wire, Photoelectric Type
INSTALLATION AND MAINTENANCE INSTRUCTIONS
FOR SM-501 SERIES DUCT SMOKE DETECTORS
PRODUCT OVERVIEW
PRODUCT APPLICATION
SM-501 Series duct smoke detectors provide early detection of smoke
and products of combustion present in air moving through an HVAC
duct supply, return, or both in commercial, industrial, and residential
applications. These devices are designed to prevent the recirculation of
smoke in areas by the air handling system’s fans, and blowers. Complete
systems may be shut down in the event of smoke detection.
NOTE
: For the correct installation of a duct smoke unit, please refer to
the NFPA 72 (National Fire Alarm Code), NFPA 90A (Standard for Installation of
Air Conditioning and Ventilation Systems),NFPA 92A (Recommended Practice for
Smoke Control Systems.), NFPA 5000 (Building Construction and Safety Code),
IMC (International Mechanical Code), and IFC (International Fire Code).
This detector is not intended for open area protection nor should it be used for
early warning detection or replace a regular fire detection system.
PRODUCT DESCRIPTION
The SM-501 Series smoke detector is fitted with a mounting base that will
accept an ionization smoke detector head model 55000-225 (or 55000-
250) or photoelectric smoke detector head model 55000-328 (or 55000-
350). The duct unit supports two sets of form “C” alarm contacts and one
form “C” trouble contact. The trouble contact supervises the presence of
the input power and removal of the detector head.
THE TROUBLE CONTACTS (TERMINALS 13-14, 15)
ARE SHOWN IN THE NON-ENERGIZED CONDITION. IN
NORMAL OPERATION,CONTACTS WILL BE REVERSED.
The trouble contacts will not operate in the event of a smoke alarm.
The SM-501 Series duct detector will operate from various input voltage
sources; namely 24VAC, 24VDC, 115VAC and 230VAC.
SAMPLING TUBES
The operating principle of a duct detector is based on the Venturi effect.
Two tubes extend into the HVAC duct. Air flowing through the duct is
forced into the air intake (inlet) tube via the air intake holes, (facing the
airflow) and passes over the detector head. The air will be drawn out
via the exhaust tube back into the HVAC duct. (A 7” exhaust tube is
provided in the installation kit.) When the concentration of smoke particles
suspended in the air stream reach the alarm threshold of the detector
head, the unit will go into alarm.
The duct smoke detector units are designed to operate in duct widths
from 6” to 10’ wide with an air velocity between 500 to 4,000 feet per
minute. To verify correct installation, the pressure differential between
the sampling (high side) and exhaust (low side) tubes should be measured
using a Magnehelic pressure gauge or equivalent. An acceptable reading is
between 0.01 and 1.2 inches of water.
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.
REMOTE ACCESSORIES
Audible and visual alarm indicators, remote status indicators, and
remote reset/test switches can be accommodated by the SM-501 Series
duct units by connecting to DC voltage output terminals 16 through
21. These terminals are not supervised and the voltage/current will
only be present when the detector unit is in alarm. The remote pilot
(green) LED will be permanently illuminated when connected to the
output terminals as long as input power and detector head are present.
SM-501 AT-A-GLANCE
MODEL NUMBER:
SM-501-N
4-Wire Ionization Duct Smoke Detector
SM-501-P
4-Wire Photoelectric Duct Smoke Detector
DETECTOR HEAD MODEL NUMBER:
Ionization Detector Head: 55000-225
Photoelectric Detector Head: 55000-328
POWER REQUIREMENTS:
STANDBY CURRENT
ALARM CURRENT
24VAC 35.0mA
24VAC
74.0mA
24VDC
15.0mA
24VDC
56.0mA
115VAC
25.0mA
115VAC
32.0mA
230VAC
12.0mA
230VAC
16.0mA
RELAY CONTACT RATINGS:
Alarm contacts:
2 Sets form “C” rated at 10A @ 115VAC resistive
Trouble contacts:
1 Set form “C” rated at 10A @ 115VAC resistive
Air velocity:
500 to 4,000ft/min.
Ambient temperature: SM-501-N: 32°F to 158°F (0°C to 70°C)
SM-501-P: 32°F to 140°F (0°C to 60°C)
Humidity:
10% to 85% RH Non-Condensing/Non-Freezing
Material:
18GA steel back box, clear plastic cover
(Makrolon 94V-0)
Finish:
Gray paint on black box
Dimensions:
9 1/8” L X 7 1/4” W X 2 1/4” H
Max. net wt.:
3 1/2 lbs.
Radioactive element: SM-501-N (Ionization) - Americium 241,
0.9 micro curie.
Do not expose to corrosive atmospheres.
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150303
Specifications subject to change without notice. | INST APD0191 D140113 | USA 150303 | Page 2 of 7
12700 Stowe Drive, Suite 100, Poway, CA 92064 | Ph: (858) 578.7887 & (888) GO.IN
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SM-501 – Installation
