FORENSICS DETECTORS FD-91 User manual

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INTRODUCTION
You have purchased the GAS LEAK DETECTOR FD-91 by
FORENSICS DETECTORSTM.The FD-91 comes in three
models and are differentiated by their color. They all have the
same functional operation.
FD-91-RED
Combustibles
Gas Leak
Detector
FD-91-YELLOW
Sewer
Gas Leak
Detector
FD-91-BLACK
Refrigerant
Gas Leak
Detector
Gas Sensitivity:
Combustibles & Sewer Gases that
include Acetone, Acetylene, Alcohols,
Ammonia, Benzene, Butane, Ethanol,
Diesel, Gasoline, Hexane, Hydrogen
Sulfide, Methane, Naphtha, Natural
Gas, Paint Thinners, Propane and
Solvents
Gas Sensitivity:
Halogenated Gases,
Freon Gases CFCs,
HFCs, HCFCs, HCs,
HFOs, R134a/R11/
R22/R404a/
R410a/R600a/R12
34yf and Blends such
as AZ-50, HP62,
MP39
Range:
(Calibrated to methane per best practice):
0-9999ppm
00 - 20.00%LEL
Range:
0-9999ppm
** ATTENTION**
Ø KEEP DETECTOR AWAY FROM EMI SOURCES
Ø STORE DETECTOR WITHIN SPECIFICATIONS
Ø DO NOT INHALE ANY GAS LEAKS
Ø IF UNWELL, SEEK CLEAN AIR & HELP
Ø KEEP AWAY FROM DUST
Ø BE VERY CAREFULLY WHEN UNDERTAKING A
MEASUREMENT OF GAS LEAKS
Ø NOT A PERSONAL PROTECTION DEVICE
Ø IF UNSURE CALL YOUR GAS COMPANY OR 911
SPECIFICATIONS
Accuracy: 5% F.S.
Response Time: < 2 seconds
Warm up: 30 seconds
Display: Color LCD, numeric ppm or %LEL, bar graph
Alarm: Visible and Audible
Alarm Point: 1000ppm or 2%LEL
Zero Calibration: Auto and Manual
Auto Off: Yes after 10 minutes
Dimensions: 6 x 2.4 x 1.2 inches
Weight: 11 oz
Power:3 x AAA 1.5V Batteries
Temperature: 30-122F
Working Humidity: 10%-90%RH
Gooseneck Length: 10 inches
Packing Items: Detector, Manual & Batteries
Sensor FD-91-RED: Semiconducting Metal Oxide
Sensor FD-91-YELLOW: Semiconducting Metal Oxide
Sensor FD-91-BLACK: Heated Semiconducting Diode
Web:www.forensicsdetectors.com
Email: [email protected]
Product Made in China, Manual Printed in the USA, Copyright © 2020

!
!
INTRODUCTION
You have purchased the GAS LEAK DETECTOR FD-91 by
FORENSICS DETECTORSTM.The FD-91 comes in three
models and are differentiated by their color. They all have the
same basic operation.
• Gas Leak Detectors are used to find gas leaks.
• The FD-91 model series is made with a flexible gooseneck
and sensor with a protecting metal cover.
• The objective of the gooseneck it to place the sensor close
to suspected gas leak locations and for the gooseneck to
allow for easier access at hard-to-reach locations.
OPERATION & TIPS
1. Press the POWER (red) button to begin. Ensure turn-on
occurs in fresh air (this is very important – fresh air).
2. A 30 second countdown will begin. Before taking a
measurement, ensure the display is reading 00.00 %LEL
or 0000 ppm.
3. If it is not, allow the unit to remain in fresh air for 5
minutes. The unit is made up of a sensitive sensor, so
thermal equilibrium may take longer depending on
environmental factors.
4. If it has yet to reach zero, then a ZERO calibration is
required. Press the ZERO button and then depress it, the
display will now read 0000 and detection can begin.
5. The unit is now ready to find a gas leak. Select SENS-H if
you are seeking the most sensitive option for small leaks
and switch to PPM for the most sensitive scale.
6. Slowly approach the suspected gas leak area. Adjust the
gooseneck so the sensor head is directed on the
suspected location. Place the sensor head as close to
the area of inspection and hold for a few seconds. Move
around connections, piping, and other areas very slowly.
7. Depending on the size of the leak, reaction times will vary
depending on gas, leak size, ventilation, dilution effects
and many others. If a crosswind or draft is present,
slower more careful measurements are needed.
8. If a reading and/or alarm is triggered take the gas leak
seriously. Act responsibly and be safe.
9. Press the POWER (red) button to turn OFF.
BATTERY POWER
Your gas leak detector is powered by 3 x AAA 1.5V. To
preserve power, the unit has AUTO-OFF after 10 minutes.
Since it has AUTO-OFF, DO NOT rely on this as continuous
monitoring for combustible personal protection equipment.
Web:www.forensicsdetectors.com
Email: [email protected]
BUTTON FUNCTIONS
PPM/%LEL button: Change the unit of measure to
display either part per million (ppm) or %LEL (lower
explosive limit). Note the device is calibrated to methane
CH4 and correcting factors to the displays will be
necessary if detecting other combustibles such as
propane, butane, or others. See product listing on the FD
website for correcting factors.
SENS button: SENS-L and SENS-H, adjust sensitivity. If
max sensitivity is required, ensure on SENS-H.
C/F button: changes the temperature unit of measur
ZERO button: press to undertake a ZERO calibration.
SPEAKER button: enables /disables audible alarm.
Alarm triggers when reading > 1000ppm or 2%LEL.
APPLICATION NOTES
NATURAL GAS LEAKS: Gas leak detectors are used
to find leaks in natural gas pipes, fittings, and
connectors. Gas leaks tend to occur with natural gas
or propane supplied to the home or business. They
can also happen with propane when cooking on the
grill, in an RV, or camping with heater products. Gas
leak detectors are used to monitor leaks in confined
spaces, silos, and tanks for any combustible gas and
vapor build up.
SEWER GAS LEAKS: Sewer gas is composed of
hydrogen sulfide, ammonia, carbon dioxide, and
methane. It is a natural by-product of human waste
and becomes a problem for homeowners when there
are leaks, clogged vents, or broken pipes. Most term
this the “rotten egg smell ” found commonly in older
sewer plumbing and buildings. Sewer detectors are
made for plumbers, inspectors, water works, HVAC,
contractors, and maintenance engineers.
REFRIGERANT GAS LEAKS: Refrigerant gas is used
in refrigeration systems to transfer heat and cool the
air. Leaks occur as seals and joints in the refrigeration
system may become worn and corroded, allowing the
refrigerant gas to leak out. Gas Leak Detectors also
allow for confirmation of proper connections.
Problems can also occur when the refrigerant is not
at the correct pressure, adding stress on the seals
and joints.