Data Sheet for Product

Siemens
Smart Infrastructure - Building Products
–2–
usa.siemens.com/fire
Profile Overview
Model OH921 provides two (2) different alarm sources that can be selected individually (ON or OFF) by the control panel.
Alarm Source 1 (Neural Network) – Combines smoke (heat) with the following field-selectable profiles:
• Standard
• D
uct
Standard: This parameter set, which is practically ideal for normal office, hotel-lobby-type applications, is the default
setting. This parameter set additional offers improved resistance to false alarms in areas where misleading
deceptive sources and helps reduce cooking nuisance alarms (UL 268 7th Ed. Listed)
Duct: When using this detector direct in air duct applications, be sure the detector is set to the parameter “Duct”.
Alarm Source 2 (Thermistor) – Heat only; provides the following:
• Static / fixed at 135°F (57°C), default setting
• Rat
e-of-Rise detection at 15°F / min. (8.3°C / min.)
If
the detector is not programmed, Model OH921 will default to a ‘standard’ profile setting, which allows operation for a
normal office-type environment. Model OH921 contains a tri-color LED indicator, capable of flashing any one (1) of
three (3) distinct colors: G
REEN | YELLOW | RED. During each flash interval, the microprocessor-based detector monitors
the following fire-system conditions:
• S
moke in its sensing chamber
• S
moke sensitivity is within the range indicated on the nameplate label
• Int
ernal sensors and electronics
Based on the results of the monitoring, the LED indicator flashes the following:
FLASH COLOR CONDITION
FLASH INTERVAL
[in seconds]
GREEN

:
Normal supervisory operation.
Smoke sensitivity is within rated limits.
10
YELLOW: Detector is in trouble and needs replacement. 4
R
ED: `
Alarm’ condition
1
NO FLASH: Detector is not powered.
–

denotes LED can be turned OFF
Please follow the corresponding description of the panel used.
A quick visual inspection is sufficient to indicate the condition of the detector at any
time. If more detailed information is required, a printed report can be provided from the
respective Cerberus PRO Modular | Model FC9-series | FireFinder XLS/V FACPs that
indicates the status and settings assigned to each individual detector.
1. Dust cover
2. Multi-criteria detector
NOTE: Each detector consists of a
dust-resistant photoelectric chamber;
a solid state, non-mechanical thermal
sensor, and microprocessor-based
electronics with a low-profile plastic
housing.
Every Model OH921 fire detector is
shipped with a protective dust
cover.
2
1. Labyrinth
2.
Optical transmitter
3.
Optical receiver
4.
Heat sensor
Model OH921
1