CEM GD-3300 User manual

User’s Manual
Combustible Gas Leak Detector
Model GD-3300

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Introduction
The Combustible Gas Leak Detector has a long,
slim gooseneck probe to find leaks in tight areas. It’s
adjustable alarm, easy one-hand operation and
impact resistance storage case add up to value and
convenience
Applications and Features include
Easily operate the Combustible Gas Leak Detector with one
hand to detect presence of combustible gases. Audible and
visual indicators help pinpoint leak source. Adjustable “tic”
rate helps eliminate background gas concentration in
contaminated environments.
• Higher Sensitivity
• Adjustable tick rate to locate leaks quickly and
easily
• Visual leak detection by LED indicators
• Precision sensor detects even the smallest leaks
• Fast response of less than two seconds to 40%
LEL
• Includes earphone Jack
• 16” gooseneck
Safety Tips

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Before using this Instrument, read all safety
information carefully. In this manual the word
"WARNING" is used to indicate conditions or
actions that may pose physical hazards to the user.
The word "CAUTION" is used to indicate conditions
or actions that may damage this instrument.
If you are using your Combustible Gas Leak
Detector as a result of a service call, chances are
someone has either smelled a combustible gas leak
or someone has reason to believe gas may be
leaking. While your Combustible Gas Leak Detector
is designed to function without producing sparks or
otherwise igniting the gasses it detects, the
environment you are responding to probably has no
such safeguards. Most combustible gas leaks are
noticed long before concentration levels build up to
the point that explosion hazards exist.

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WARNING!
If you feel an explosion hazard exists:
• Arrange for evacuation of people in the area
• Call proper authorities from a safe location
• Shut off gas source is possible
• Ventilate enclosed areas if possible to do so
without risk of ignition
• DO NOT switch power switches on in area of
question
As a matter of routine, ventilate the area you plan to
work in. Ventilation will help ensure the gas does
not accumulate in large volume where it can attain
its Lower Explosive Limit (LEL)*
LEL: Lower Explosive Limit - The point at which a
combustible gas, when mixed with air, has
developed the minimum concentration to combust
when exposed to a source of ignition. The LEL is
usually stated as a percentage of gas in air, as a
fuel-air-ratio, or as parts-per-million (PPM) in a
International Symbols

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Important Information; see manual
Conforms to European Union directives
Controls and Indicators
1. Sensor Tip Guard
& Sensor (internal)
2. Gooseneck Probe
3. Alarm Light
4. Ready Light (Power-On)
5. Power ON/OFF Slide Switch
6. Earphone Jack
7. Tic Rate (Sensitivity) Adjustment
8. Probe Clip
9. Hand handle
10. Batteries cover
Instructions
Switch on the gas-leak detector by sliding the
ON/OFF button and the READY light is glowing.
The Combustible Gas Leak Detector runs through a
one-minute warm-up and self-zeroing sequence
when it is first turned on in fresh air. The alarm of
the instrument may very loud without contact any

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gas. That is caused by the high Tic Rate preset in
rotary wheel.
Rate (Sensitivity) Adjustment
Each time the instrument is put into service, you
should conduct a quick functional test. Adjust the
Tic Rate to non-alarm level. Then, simply expose
the sensor to a known leak, like a cigarette lighter,
or pass the probe over a drop of combustible fluid.
After the initial warm-up, the instrument can be used
to detect combustible gasses. When the sensor in
the probe tip detects a combustible gas, the tic rate
will increase and the instrument sounds a warbling
tone while the ALARM light. As the concentration of
gas increases so does the tic rate.
If the situation calls for quiet operation, or if
background noise makes it difficult to hear the
built-in speaker, you can use an earphone. The jack
is at the top of the instrument. Note that listening to
the alarm or tic through the earphone is very loud.
If the READY light is off, the batteries are low. They
should be replaced immediately. Low batteries will
adversely affect the instrument’s reliability. See the
replacement procedures.
Adjusting the Tic Rate(Sensitivity)

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The tic rate tells you when the sensor (in the tip of
the instrument) is getting close to a leaking gas. You
can control the tic rate using the rotary wheel in the
center of the instrument.
Move the wheel clockwise to increase the
frequency
Move the wheel counter-clockwise to decrease
the frequency
A tic rate of 4 to 8 tics per second, in fresh air, is
typical. As the sensor comes near a combustible
gas source, the tic rate increases. In order to isolate
the source of a leak, you may need to move the
wheel counter clockwise, decreasing the sensitivity,
as the sensor moves closer.
Replacing the Batteries
Replace your 1.5 volt /size R14C(B) alkaline
batteries when:
• The green READY light off
• No light or other activity occurs upon turning the
instrument on
To replace the batteries:
1. Lay the instrument face-down on a back face.
2. Remove the battery cover. Apply upward
pressure to the tab at the bottom of the battery
cover while lifting it out.
3. Remove the batteries using a coin or screwdriver,
if necessary, to pry them out.
4. Replace all three batteries with new ones.

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Replacing the Sensor
Although the sensor is designed to offer many years
of reliable service, it may become inoperable if it is
submerged in liquid or otherwise physically
damaged.
To replace sensor:
1. Turn the instrument off
2. Remove the upper tip guard by pressing straight
up from the alignment notch that separates the
two halves of the tip guard.
3. This is a sturdy component, but use caution
bending its leads.
4. Pull the sensor straight up from its tip housing.
5. Replace the sensor, pressing it straight in.
6. Reassemble in reverse order.

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Specifications
Sensitivity…………….. 50 ppm methane
Sensor Type…………. Low power semiconductor
Warm Up Time……….. Approx.60 seconds
Response Time………. Less than 2sec. (up to 40%
LEL)
Duty Cycle…………….. Continuous
Probe Length………….. 16"
Power Supply…………. 3”C” cell batteries
Battery Life……………. 8 hours continuous use,
typical
Alarm……………………Visible & Audible at 10%
LEL for Methane. Can be
calibrated for other
concentrations or gases.
Warranty……………….. 1 year
Operating Conditions
To ensure accurate readings use it only when
ambient air is within this range:
Temperature: 32 to 120°F
Humidity: 10 to 90% RH (non condensing)
Gasses Detected
The GAS detects a wide variety of gasses, including
some toxic gasses, and nuisance vapors. The
following lists represents only a portion of the more
common gasses it will detect.

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Combustible:
oNatural Gas
oPropane
oButane
oMethane
oAcetone
oAlcohol
oAmmonia
oSteam
oCarbon Monoxide (not to quantify)
oGasoline
oJet Fuel
oHydrogen Sulfide
oSmoke
oIndustrial Solvents
oLacquer Thinner
oNaphtha

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