General NGD269 User manual

COMBUSTIBLE GAS LEAK DETECTOR
WITH DIGITAL LEVEL READOUT
USER MANUAL
NGD269
Read this manual carefully and thoroughly before using the product.

TABLE OF CONTENTS
 
 
 
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INTRODUCTION
Thank you for purchasing eneral Tools & Instruments’ ( eneral’s) N D269 Combustible as Leak Detector with Digital Level
Readout. The N D269 is ideal for checking automotive exhaust and fuel systems, liquid- and gas-fired heating systems,
propane tanks and filling stations, cracked heat exchangers and manholes/sewers.
KEY FEATURES
• Detects the presence of most combustible gases without measuring or displaying their concentration. The unit’s analog bar
graph, and the speed and tone of its audible alarm, enable the N D269 to pinpoint the location of a gas leak by comparing its
responses to gas exposure at different points.
• Measures and displays the concentration of CH4(methane/natural gas), C3H8(propane) and H2(hydrogen) for reference
purposes. Readings are displayed in digital form in ppm, %LEL (lower explosive limit) or %Vol (percentage by volume).
The digital readings provide a third basis for comparing gas levels at different locations.
• High-sensitivity, durable semiconductor gas sensor
• Automatically self-tests all circuitry (including the gas sensor) upon startup
• Measurements of CH4, C3H8and H2are calibratable at multiple points over specific ranges using a simple sequence of
interactions with on-screen interfaces
• 13 in. (330mm) long flexible gooseneck probe
• Fast warmup and response times
• One button press makes the ambient environment the measurement baseline
• Headphone jack
• On-screen battery status indication
• Powered by a rechargeable 3.6V Ni-MH (nickel–metal hydride) battery
• Comes in a hard plastic carrying case along with a 110VAC battery charger
• 1-year limited warranty
2

SAFETY INSTRUCTIONS
• WARNING: NEVER use an open flame (from a cigarette lighter or candle, for example) to help search for gas leaks in dark
areas.
• WARNING: NEVER charge the N D269’s battery in an environment where combustible gases may be present.
WHAT’S IN THE PACKAGE
The N D269 comes in a hard plastic case along with a 120VAC-powered battery charger and this user’s manual.
PRODUCT OVERVIEW
Fig. 1 shows the key components of the N D269. Fig. 2 shows a typical readout in detection mode. Use Fig. 1 to familiarize yourself
with the position and function of all components before moving on to the safety, setup and operating instructions.
Fig. 1. The NGD269’s key components
3
NGD269
1.
3.
4.
5.
2.
6.
7.
8.
Unit
Off
NGD269
1. LCD
2. power on/backlight button. Also used during
calibration.
3. alarm mute button. Also used to select the
measurement unit, and during calibration.
4. Zero button. Press to make the gas concentration of the
current ambient air the measurement baseline. Also used to
power the unit off, select the measurement unit, and during
calibration.
5. as sensor assembly
6. 13 in. (330mm) long sensor-tipped gooseneck probe
7. Battery charging jack
8. Headphone jack. Accepts a standard 3.5mm mini-stereo
plug.
Zero

Fg. 2. A typical readout in detection mode
1. Analog bar graph readout. The percentage of detected gas concentration vs. the full selected measurement range (in the above
example, 57%).
2. resent value ( V) of percentage gas concentration (a digital representation of the bar graph readout); in the above example,
the PV is 57%.
3. 00. Multiplier of concentration percentage, based on the selected measurement range. In the above example, multiplying “57” by
“00” yields the measured gas concentration of 5700 ppm.
4. ppm. Selected measurement unit. The above example shows ppm; other options are %LEL (for lower explosive limit) and %Vol
(percentage by volume).
5. 8600. The maximum value of gas concentration in the selected measurement range; in the above example, the maximum value is
8600 ppm.
6. . Battery charge status. The above screen shows the icon for remaining battery charge. Other possible icons are (full
battery), (low battery charge), (battery too low; needs charging), and (battery dead; cannot power unit on).
7. Audible alarm status. On the above screen, the icon indicates that the audible alarm is “on” (the default status). The icon
would indicate that the alarm has been muted.
SETUP INSTRUCTIONS
CHARGE THE BATTERY
Before using the N D269 for the first time, charge the battery by plugging one end of the included charger into a 110VAC power
source and the other end into the battery charging jack on the left side of the unit (Fig. 1, Callout 7). During charging, it is normal for
the back of the unit to feel warm.
Normally, charging a dead battery to full capacity takes four to six hours. The display will indicate CHARGING OVER when charging
is complete, indicating that it’s safe to unplug the charger from the unit and return it to the carrying case.
eneral recommends re-charging the battery within 12 hours following each measurement session to guarantee that the N D269 is
available for immediate use.
OPERATING INSTRUCTIONS
To power the NGD269 on, press and hold the button for more than two seconds. The unit will then perform a brief self-test of
its circuitry, followed by a warmup period that typically takes five seconds. If the sensor is nearing the end of its useful life, or the
instrument has not been used in a long time, the warmup period may take longer.
Following the self-test and warmup sequences, the N D269 will automatically enter detection mode. By default, detection mode
begins with the backlight off and the audible alarm on. To turn the backlight on, press the button.
DETECTING COMBUSTIBLE GASES
Although a properly calibrated N D269 can measure the concentrations of three combustible gases (methane/natural gas, propane
and hydrogen), it can only detect the presence of several other combustible gases (butane, for example) without measuring their
concentration.
4
1.
2.
3.
5.
6.
4.
ppm

In detection mode, changes in the width of the bar graph readout as the probe is moved around pipes and fittings are a reliable
proxy for higher and lower detected gas concentration at specific locations. So, too, are the characteristics of the instrument’s
audible alarm, which sounds at a speed and frequency proportional to the measured gas concentration. The higher the
concentration, the faster the beep and the higher the tone. To mute the alarm, press the button. This will change the icon in
the upper right corner of the display from to .
If you are working in a noisy environment, eneral recommends leaving the alarm on and using headphones to avoid missing any
changes in gas concentration reflected by changes in alarm characteristics. The headphone jack on the left side of the N D269 (Fig.
1, Callout 8) accepts a standard 3.5mm mini-stereo plug.
MEASURING CH4, C3H8AND H2
The N D269’s digital readout gives you a third way to compare local concentrations of methane/natural gas, propane and hydrogen
(assuming the instrument has been properly and recently calibrated). The callouts below Fig. 2 explain how to convert the values
shown on the screen to concentrations. Bear in mind that for methane/natural gas, propane and hydrogen, displayed concentration
values are relative, rather than absolute. They are also most accurate for target gas concentrations within the selected measurement
range.
When powered on, the N D269 will begin displaying gas concentrations using the last selected measurement unit. To change the
measurement unit, press the and Zero buttons at the same time to cycle through the three measurement unit options: ppm,
%LEL (lower explosive level) and %Vol (percentage by volume).
To make it easier to detect gas leaks in any setting, the N D269 allows you to make the gas concentration of the working
environment the measurement baseline. To do so, press the Zero button.
To power the NGD269 off, press the and Zero buttons at the same time.
CALIBRATION
To make its relative measurements of methane/natural gas, propane and hydrogen concentration as accurate as possible, eneral
recommends calibrating the N D269 at least once every six months for each gas it is expected to measure. The instrument can be
calibrated for one, two or all three potential target gases during a single session.
Calibration for a particular gas requires having one or more cylinders (each with a different concentration) of a standard reference
gas on hand. Often called calibration gases, they are readily available from multiple vendors as individual cylinders, or bundled with
a flow regulator in a kit.
STEP 1. ENTER CALIBRATION MODE
To begin, with the unit powered off press the and buttons simultaneously. The unit will respond by powering on with a
display that initially shows the text DEMARCATE . . . After a few seconds, a three-minute warmup will begin, with the display
counting down the remaining warmup time in seconds.
STEP 2. SELECT A GAS AND RANGE
Once warmup is complete, the screen will automatically display the following interface (with C3H8or H2possibly replacing
CH4, and showing a different range as well.)
To change the target gas from the one first shown, press the button to cycle through
the three options: CH4(methane/natural gas), C3H8(propane) and H2(hydrogen).
For each target gas, the value on the RANGE line will change to one of its available
measurement ranges. To change the range for the selected target gas, press the
Zero button to cycle through the available ranges (in ppm) for that gas.
5
GAS:
RANGE:
SAVE
CH4
30000
A typical display during Calibration Step 2
For CH4(methane/natural gas), the available ranges are:
• 0 to 10,000 ppm (0 to 20%LEL or 0 to 1%Vol);
• 0 to 20,000 ppm (0 to 40%LEL or 0 to 2%Vol);
• 0 to 30,000 ppm (0 to 30%LEL or 0 to 3%Vol); and
• 0 to 50,000 ppm (0 to 100%LEL or 0 to 5%Vol)
For C3H8(propane), the available ranges are:
• 0 to 10,000 ppm (0 to 48%LEL or 0 to 1%Vol); and
• 0 to 20,000 ppm (0 to 96%LEL or 0 to 2%Vol)
For H2(hydrogen), the only available range is
0 to 10,000 ppm (0 to 25%LEL or 0 to 1%Vol).
Once you have selected a target gas and its measurement range, press the button to proceed to the next step.

STEP 3. SET AND SAVE CALIBRATION POINTS
At this point in the calibration sequence, pressing the button changes the display to an interface specific to the selected target
gas as well as its chosen measurement range. The screen below shows the interface used to calibrate the N D269’s measurements
of CH4concentration over a range of 0 to 30,000 ppm (the two column headers).
A typical display during Calibration Step 3
Note the presence of a check mark (√) at the right of multiple values (representing the
available ranges for the target gas) in the left column. Also note that the range value
highlighted in the left column (in this case, 0) is accompanied by a highlighted value in
the right column on the same line (in this case, 80). Values in the right column represent
conversion factors for real-time measurements of reference gas concentration. During
each calibration, the N D269 compares the factor to a theoretical benchmark value for
the target gas at a specific concentration. The instrument then adjusts its sensitivity to
the gas in order to minimize the difference in values.
To thoroughly calibrate the instrument for a particular gas, you must perform separate calibrations for every range value
accompanied by a check mark. Calibration of unchecked ranges is optional.
To navigate this interface:
• Use the Zero button as you would a down arrow key (). Pressing this key with the bottom line of a column highlighted
moves the cursor up to highlight the value at the top of the column.
• To save a highlighted value, press the button (directly below SAVE)
• To return to the Step 2 interface (in order to calibrate for a different target gas), press the button (directly below BACK).
To perform the calibration(s), use the Zero button to navigate to and highlight the uppermost checked range value in the left
column. Next, insert the tip of the gooseneck probe into a cylinder of reference gas of the type and concentration shown on
the screen.
Exposing the sensor to the calibration gas will produce a change in the highlighted value in the right column. After the value
stabilizes, press the button to save it. Doing so will add an asterisk (*) at the left of the value. If the displayed value
fluctuates a bit before you remove the probe from the cylinder, you can press the button again to update the calibration point.
Next, use the Zero button to navigate down to, and highlight, the next range in the left column with a check mark (if any exist). Then,
insert the tip of the gooseneck probe into a new cylinder of reference gas of the type and concentration shown on the
screen. Again, wait until the highlighted value in the right changes and stabilizes. Finally, save the stabilized value by pressing the
button and updating it (if you wish) before removing the probe.
Repeat the above steps until all ranges in the left column with a check mark also have an asterisk on their line in the right column.
To complete calibration for the target gas over the range selected in Step 2, use the Zero button to navigate down to, and
highlight, SAVE at the bottom of the left column. Then press the button to save the calibration point(s) for the target gas. If
calibration succeeded, OK will appear on the bottom of the screen.
However, if any value in the right column with an asterisk is very different from its benchmark value, ERROR! will appear at the
bottom of the screen to indicate that calibration of the target gas at the current concentration has failed. In this case, eneral
suggests that you use a different cylinder of reference gas and try again. If calibration fails again, contact eneral’s tech support
department (at [email protected]) to discuss your options.
To calibrate N D269 measurements of the same target gas over a different range, or calibrate measurements of a different target
gas, press the button (directly below BACK) to return to the Step 2 interface and make a new selection.
After completing your calibration(s), power the N D269 off by pressing the and Zero buttons at the same time. Then plug in
the battery charger so the instrument will be immediately available the next time it is needed.
6
CH4 30000
0 * 80
1000
5000
10000
30000
SAVE BACK
✓
✓
✓

OPERATING & MAINTENANCE GUIDELINES
• When using the measurement units ppm and %LEL, do not expose the sensor to gas concentrations exceeding the
selected range over a long period of time. Doing so will compromise measurement accuracy and possibly damage the
sensor.
• Likewise, avoid exposing the sensor to any environment containing silicon or compounds of lead, sulfur or organic
phosphorus. Doing so will “poison” the sensor.
• Along the same lines, avoid long-term exposure of the sensor to any environment containing hydrogen sulfide,
hydrocarbon gas or any highly corrosive gas. Doing so will compromise the response of the sensor and reduce its
sensitivity.
• Finally, do not expose the N D269 to electric or mechanical shocks, a strong magnetic field, sunlight or high
temperatures.
• Charge the battery within 12 hours following each measurement session to guarantee that the unit is available for
immediate use. Also make sure to fully charge the battery before placing the N D269 into long-term storage, and
whenever you don’t expect to use it for months.
• Never use a sensor that appears defective (due to a crack in its housing, for example), or especially one that produces the
on-screen warning SENSOR FAIL! The sensor has an average useful life of two years.
• Using spare parts from an unknown source, or a battery charger other than the one supplied voids the N D269’s one-year
limited warranty. Attempting to disassemble or repair the instrument also voids the warranty.
SPECIFICATIONS
ases detected without concentration measurements Most combustible hydrocarbon gases
ases whose concentrations are measured CH4(methane/natural gas)
on a relative basis C3H8(propane)
H2(hydrogen)
Available measurement ranges For CH4:
0 to 10,000 ppm (0 to 20%LEL or 0 to 1%Vol);
0 to 20,000 ppm (0 to 40%LEL or 0 to 2%Vol);
0 to 30,000 ppm (0 to 30%LEL or 0 to 3%Vol);
0 to 50,000 ppm (0 to 100%LEL or 0 to 5%Vol)
For C3H8:
0 to 10,000 ppm (0 to 48%LEL or 0 to 1%Vol);
0 to 20,000 ppm (0 to 96%LEL or 0 to 2%Vol)
For H2:
0 to 10,000 ppm (0 to 25%LEL or 0 to 1%Vol)
Sampling method Natural diffusion
Response time < 5 seconds
Sensor type Semiconductor
Sensitivity Better than 50 ppm
Sensor life Two years
LCD size 1-5/8 in. (41mm) diagonal
Power supply Rechargeable 3.6V Ni-MH (nickel–metal hydride) battery rated at
2200mAh, with a useful life of two years/300 recharging cycles
Charging time Four to seven hours
Operating temperature 14º to 132ºF (-10º to 55ºC) at <95% RH
Storage temperature -22º to 140ºF (-30º to 60ºC) at <95% RH
Dimensions 7.1 x 2.8 x 1.4 in. (180 × 72 × 35.5mm)
Weight 10.6 oz. (300g)
Limited warranty term 1 year
7

WARRANTY INFORMATION
eneral warrants its instruments and accessories, and digital tools products against defects in material or workmanship for one year
from the date of purchase unless otherwise stated on the packaging, user’s manual, and/or marketing materials. eneral also
warrants its non-digital tools products against defects in material or workmanship on a limited lifetime term.
eneral will replace or repair the defective unit, at its option, subject to verification of the defect.
This warranty does not apply to defects resulting from abuse, neglect, accident, unauthorized repair, alteration, or unreasonable use
of the product. It also does not cover products purchased from unauthorized distributors. A proof of purchase must accompany each
warranty claim.
Any implied warranties arising from the sale of a eneral product, including but not limited to implied warranties of merchantability
and fitness for a particular purpose, are limited to the above. eneral shall not be liable for loss of use of the product or other
incidental or consequential damages, expenses, or economic loss, or for any claim of such damage, expenses, or economic loss.
State laws vary. The above limitations or exclusions may not apply to you.
For more details or to file a warranty claim, contact eneral Tools & Instruments Technical Support at [email protected].
RETURN FOR REPAIR POLICY
Every effort has been made to provide you with a reliable product of superior quality. However, in the event your instrument requires
repair, please contact our Customer Service to obtain an R A (Return oods Authorization) number before forwarding the unit via
prepaid freight to the attention of our Service Center at this address:
eneral Tools & Instruments
75 Seaview Drive
Secaucus, NJ 07094
212-431-6100
8
©2018 GENERAL TOOLS & INSTRUMENTS
Secaucus, NJ 07094
www.generaltools.com (800) 69 -8665
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