ECO SENSORS, INC.
MOUNTING HOLES
4.7 mm (3/16”) dia.
OZONE SWITCH™
Model OS-3
73mm ( 2 7/8”) centers.
INSTRUCTIONS FOR USE
GENERAL
The model OS-3 acts like a thermostat to control ozone generators and alarms based on an
adjustable ozone set-point.The standard available range is 0-10 ppm.The design incorporates
hysteresis or a “dead band” to avoid system “chatter.”The SPDT relay contacts will handle up
to 5 amps at 250 volts or up to a 1/8 HP motor.The OS-3 should not be used in the presence
of acid gases, strong VOC’s, or strong halogen fumes.
The instrument is conditionally warranted for one year. Save a copy of your purchase document
as a proof of purchase and date, and read the warranty statement at the and of this manual.
Precalibrated sensor module SM-10.
Plugs into 1 meter cable from the OS-3.
OPERATION
First, verify that the instrument is working as received. Connect your AC adapter to the power
jack or your 12-24 V DC supply to terminals 4 and 5 of terminal block TB1 found on the inside
back of the instrument. Caution!: Many AC adapters and DC supplies deliver a higher voltage
than on the nameplate - “24 volts” can be 32 volts, etc.Verify that the voltage to the input does
not exceed 24 volts and that it is not AC. In either case, major damage to the instrument can
result.
SPECIFICATIONS
The sensor must be conditioned to burn off chemicals it may have absorbed during shipping
and storage before it develops full ozone sensitivity.
Sensor: Heated metal oxide semiconductor. Operates at 200 degrees C. The sensor is
incorporated in a precablibrated preamplifier module which plugs with a cable from the OS-3
Ozone Switch™
Standard operating range: 0-10 ppm.
Accuracy: 20% in the .5-10 ppm range.
Allow 1-8 hours warm-up before attempting to test the instrument and at least 24 hours
before using the instrument.
Response time: Within 2 minutes of when ozone reaches the sensor.
Temperature and humidity range: 50-80 deg F (10-27 deg C).
For indoor use only. 30-60% relative humidity.
Supply voltage required: 12-24 volts DC, 200 mA. Ground -
Adapter plug: 5.5mm/2.5mm female, center +.
It is recommended to test the instrument for positive response with an ozone generator when
the instrument is received and again at the site where the instrument is installed.Eco Sensors,
Inc. offers an inexpensive battery-operated, hand-held ozone generator for this test purpose,
the Model OG-1.
Adjust the set-point if required. It should not be set below .5 ppm. A data logger can be
connected toTB1 terminals 1 and 2.The output will be 0-2 volts.Voltage readings are directly
proportional to the ozone concentration on a scale of 1 volt = 10 ppm.
Relay contacts rating: SPDT non-latching, 5 amps, 250 volts AC, or 1/8 HP inductive load.
Size: 3" X 2 1/2" X 15/8" (76 X 64 X 42 mm).
Weight: 5 oz. (140 grams).
Conformity: This product conforms to the European Community ICE) requirements for
emissions (EMI) and interference immunity.
You can now connect the Ozone Switch(tm) to external devices such as an ozonator to be
controlled or an alarm circuit. Disconnect the power to the generator control wiring and the
DC power to the instrument while connecting the wiring. Bring the external wiring through the
bottom access hole of the instrument or drill the access holes as required. Wire generator
control circuits only to terminals 2 and 3 of the terminal block TB2. Do not leave oils, solvents,
or greases on, In, or near the Instrument. Their fumes, however, minor, can cancel the
instrument’s ozone responsiveness.
SAFETY FEATURES
Loss of power protection: relay opens (shuts off generator) when the instrument loses Power,
Enclosure: Flame retardant ABS, UL approved. Relay: UL and CSA approved.
Electrical: (a) Circuits operate at 24 volts, 200 mA or less. (b) Power input circuitry includes
automatically resetting fuse, polarity reverse protection diode, and overvoltage protection
diode.
CALIBRATION
PRECAUTIONS
The Ozone Switch(tm) is shipped from the factory calibrated to detect at 10 ppm. Lower
values than that are settable by the calibrated control found by opening the back cover. The
calibration should be within 20% from .50-10 ppm. We do not recommend operating with a
set-point for detection below .50 ppm.The calibration will be affected by greases, oils, solvents
and other VOC generators in the area (sensitivity will appear to be reduced), or by extremes
of temperature and humidity by oxidizing chemicals such as acid gases (sensitivity will appear
to be increased). Note that the instrument should be recalibrated after changing the sensor
and at least annually. Rough- check of the instrument’s functionality should be made every
three months by presenting it with ozone and verifying that It detects.
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Allow at least 1-4 hours warm-up for functionality testing and 24 hours warm-up for
operational use.
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Read all the instructions in this manual.
Keep the instrument dry. Never let water or other liquids into the sensor.
Do not drop the instrument or subject it to continuous vibration.
Do not store or operate the instrument in high levels of dust.
When operating at lower temperatures or high humidity, such as warehouses or refrigerated
areas, for correct and reliable operation please contact Eco Sensors or your distributors
about special provisions.
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Do not attempt to service the instrument yourself.Service should only be done by authorized
technicians, or you will void the warranty.
Do not clean the instrument with cleaning chemicals or solvents. Clean it with a damp
cloth.
Do not operate the instrument near heavy aerosols (spray) usage or where oxygen is
being administered.
The sensor element, which is very small, operates at a temperatures of about 200 deg C
(392 deg F). Do not operate the instrument where this could be a problem.
Do not operate the instrument or rely on its readings where there are high concentrations
of:
SERVICE AND MAINTENANCE
Do not attempt to do board-level repairs yourself. This will void the warranty.
SENSOR - The ozone sensor is incorporated into a precalibrated module, part no. SM-10.
This plugs into the cable from the OS-3. In the event of a sensor failure or deviation from
correct calibration, the senor module should be replaced rather than trying to repair or
recalibrate it.
AC POWER ADAPTERS - The Ozone Switch(tm) will not operate properly if it is not receiving
12-24 V DC at 200 mA. Check your power supply circuit or AC adapter to ascertain that it is
“on” and is supplying the correct power. AC adapters can burn out during lightening strikes or
other electrical surges, but this is very unlikely that the Ozone Switch(tm) will completely fail
during such surges due to its extensive input power protection circuity. Eco Sensors can
supply AC adapter for North America. Elsewhere, AC adapters should be purchased through
our distributors or locally using specifications found on the Eco Sensors website
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Chlorine or other halogen compounds
Sulfur compounds
Strong VOC’s (hydrocarbons)
Urine residues and ammonia compounds
Acid gases such as sulfuric or nitric acid fumes
When in doubt, operate the instrument at least 24 hours in your worst case environmental
condition to see if it will operate properly.
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