ION GasCheck G User manual

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GasCheck G
Instrument User Manual V2.4R
Unrivaled Gas Detection. Ionscience.com/usa

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GasCheck G Instrument User Manual V2.4R
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EU Declaration of conformity
The EU Authorised Representative of the manufacturer Ion Science limited has sole responsibility, on the date this product
accompanied by this declaration is placed on the market, the product conforms to all technical and regulatory requirements of the
listed directives
Authorised Representative: ISM Deutschland GmbH · Laubach 30 · D-40822 Mettmann, Germany
Product: GasCheck G 1, 2 and 3 (Graphical)
Product description: Handheld micro thermal conductivity sensor used to detect gas leaks. This instrument
has been designed specifically for search and location of non-flammable gases such as
helium and CFC’s.
Directive: EMC Directive (2014/30/EU)
LVD Directive (2014/35/EU)
Standards:
EN IEC 61010-1:2010 Safety requirements for electrical equipment for measurement, Control, and laboratory use
–Part 1: General requirements
EN ISO/IEC ISO 9001:2015 Quality management systems –Requirements
EN I 61326-1:2013 Electrical Equipment for measurement, control and laboratory use
EMC Requirements (Class B and General Immunity)
Name: Clemens A. Verley Position: Chief Executive Officer
Signature: Date: 31st December 2020

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Contents
EU Declaration of conformity .................................................................................................................................................. 3
Statements............................................................................................................................................................................. 5
Safety.....................................................................................................................................................................................................5
Quality Assurance..................................................................................................................................................................................5
Responsibility of use..............................................................................................................................................................................5
Disposal .................................................................................................................................................................................................5
Calibration Facility.................................................................................................................................................................................5
Legal Notice ...........................................................................................................................................................................................5
Instrument description............................................................................................................................................................ 6
Packing list ............................................................................................................................................................................. 7
How GasCheck G works........................................................................................................................................................... 8
Thermal Conductivity ............................................................................................................................................................................8
Replacing batteries ................................................................................................................................................................. 9
Getting started ..................................................................................................................................................................... 10
The Keypad..........................................................................................................................................................................................10
Instrument main menu ......................................................................................................................................................... 11
Running screen ..................................................................................................................................................................... 12
Gas selection .......................................................................................................................................................................................12
Sensitivity ............................................................................................................................................................................................12
Battery status ......................................................................................................................................................................................12
Backlight ..............................................................................................................................................................................................12
Gas measurement ...............................................................................................................................................................................12
Sound indication..................................................................................................................................................................................12
Bar graph .............................................................................................................................................................................................12
Peak hold.............................................................................................................................................................................................12
Functions ............................................................................................................................................................................. 13
Contrast...............................................................................................................................................................................................13
Backlight ..............................................................................................................................................................................................13
Sound...................................................................................................................................................................................................13
Peak hold.............................................................................................................................................................................................13
Calibration ...........................................................................................................................................................................................13
Battery selection .................................................................................................................................................................................14
View Data ............................................................................................................................................................................................14
Units ....................................................................................................................................................................................................14
Display .................................................................................................................................................................................................14
Gas selection .......................................................................................................................................................................................15
Upgrade...............................................................................................................................................................................................15
Using GasCheck G ................................................................................................................................................................. 17
Probe options....................................................................................................................................................................... 18
Detecting leaks..................................................................................................................................................................... 19
Overview .............................................................................................................................................................................................19
Calibration ........................................................................................................................................................................... 20
Overview .............................................................................................................................................................................................20
Selecting Factory or Custom Calibration.............................................................................................................................................20
Calibration procedure using 'ppm' units.............................................................................................................................................20
Calibration procedure using 'cc/sec' units ..........................................................................................................................................21
Instrument specifications ...................................................................................................................................................... 22
40 Hours (20 hours when using the backlight) ........................................................................................................................ 22
Replacing parts..................................................................................................................................................................... 22
Instrument warranty and service........................................................................................................................................... 24
Warranty .............................................................................................................................................................................................24
Service .................................................................................................................................................................................................24
Contact details.....................................................................................................................................................................................25
Manual log ........................................................................................................................................................................... 26

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Statements
Safety
Please read this manual in full before using the GasCheck G instrument. ION Science Inc takes no responsibility
for damage, injury or death resulting from misuse, misunderstanding or negligence while using this gas detector.
Please contact ION Science Inc via the address below for clarification on any aspect of this manual that is not
understood or for additional information required.
This instrument should only be used by qualified or competent persons with suitable knowledge of the hazards
relating to the gases contained within equipment or in the local environment.
Quality Assurance
GasCheck G instruments are manufactured by ION Science Inc within an ISO 9001:2015 compliant quality system,
which ensures that the equipment supplied to our customers has been designed and assembled reproducibly,
and from traceable components.
Responsibility of use
Many gases are hazardous and can cause explosion, poisoning and corrosion resulting in damage to property and
life. It is the responsibility of the person using this instrument to ensure it is being used in accordance with this
manual and that the instrument is functioning correctly before use.
The GasCheck G can detect a large range of gases but some gases are more difficult to detect.
It is the responsibility of the user to ensure the GasCheck G instrument has the sensitivity to detect the required
gas before reaching potentially dangerous levels.
Inadequate performance of the gas detection equipment described in this manual may not necessarily be self-evident
and consequently equipment must be regularly inspected and maintained. Ion Science recommends that personnel
responsible for equipment use institute a regime of regular checks to ensure it performs within calibration limits, and
that a record be maintained which logs calibration check data. The equipment should be used in accordance with this
manual, and in compliance with local safety standards.
Disposal
Disposal of GasCheck G, its components and any used batteries shall be in accordance with local and national
safety and environmental requirements. This includes the European WEEE (Waste Electrical and Electronic
Equipment) directive. Ion Science Ltd offers a 'take-back' service. Please contact ION Science Inc for more
information.
Calibration Facility
Ion Science Ltd offers a calibration service including the issue of a traceable certificate valid for 12 months. A
GasCheck G Calibration Kit offers a means of checking and calibrating the instruments against a known reference,
however ION Science Inc strongly recommend the instrument is returned to an approved service center on an
annual basis for general maintenance and calibration.
Legal Notice
While every attempt is made to ensure the accuracy of the information contained in this manual, ION Science accepts
no liability for errors or omissions, or any consequences deriving from the use of information contained herein. It is
provided "as is" and without any representation, term, condition or warranty of any kind, either express or implied. To
the extent permitted by law, ION Science shall not be liable to any person or entity for any loss or damage which may
arise from the use of this manual. We reserve the right at any time and without any notice to remove, amend or vary
any of the content which appears herein.

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Instrument description
The GasCheck G is a range of portable handheld gas detector instruments predominantly used for detecting gas leaks
and can detect almost all gases to varying degrees. Being a handheld instrument, it is powered by standard AA size
batteries and will accept both Alkaline and Nickel Metal Hydride (rechargeable) types.
The GasCheck G uses thermal conductivity as it's means of detecting gas which offers a robust sensor technology that
requires practically no maintenance beyond annual servicing.
All GasCheck G models have an easy to use graphical interface with an intuitive keypad allowing simple function
selection and adjustment.
The GasCheck G is a range of instruments that can be upgraded to add features without the need to be returned to
the supplier and without having to modify the internal firmware.
GasCheck G has an LCD display, LED indicator and audible sounder that indicates the detected signal.
Common applications where The GasCheck G is already used include:
* Quality assurance - Testing seal integrity after product manufacture
* Laboratory applications - Detection of leaks from mass spectrometers and chromatograph
equipment
* Industrial - Leaks from gas cylinders, pipe work and process equipment
* Medical - Testing of membrane materials and sealing of glove boxes
* Pneumatic - Valve seal testing
The GasCheck G is calibrated against a 5 E-4 cc/s Helium leak to allow volumetric readings and also a 5000ppm Helium
to allow measurement of concentrations.
Selectable units:
cc/sec Cubic Centimeters per Second offers a reading that indicates the volume of gas escaping into
atmosphere from a single point. ie. leakage from a hole in a gas filled vessel or pipe.
ppm Parts Per Million is a concentration reading, GasCheck G will display the concentration being
detected however it is more difficult to gauge the quantity of leakage.
mg/m3Milligrams per meter cubed is also a unit that measures concentration. (See ppm above)
g/yr Grams per Year is an alternative measure of leak rate.
The GasCheck G range is NOT intrinsically safe so should not be using in a potentially
explosive environment.
Ambient air pressure, heat and humidity can also affect readings.
The GasCheck G range is NOT 'Gas Specific' i.e. It can NOT differentiate between gases.

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Packing list
Please remove all packing material and then check the content of the carry case against the list below before use. Should
the instrument or any accessory appear damaged or missing then contact the instrument supplier for advice before use.
Item
Qty
Description
Check
1
1
GasCheck G instrument with short probe and nozzle fitted
2
1
Long probe
3
1
Box spanner used to change probes
4
1
Spare battery clip
5
1
Quick Start Guide
6
1
Calibration certificate







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How GasCheck G works
Thermal Conductivity
All gases conduct heat but by varying amounts, if an object is heated and then the source of heat is removed, the
object will eventually cool down to match ambient air temperature. This action occurs because the ambient air
surrounding the object carries the excess heat into the surrounding atmosphere.
This principal is also the same for objects that are cooler than the surrounding ambient air.
Dissipation of heat into an air atmosphere is known and is a predictable rate however, if the ambient air is replaced
with an alternative gas like Helium the rate at which an object cools down changes.
If the object mentioned above had it's environment replaced with pure Helium it would cool down to the environment
temperature about 6 times faster.
The GasCheck G contains a heated thermistor bead that transmits heat to a block of material that remains at a
constant temperature. As air passes through the detector chamber a constant amount of heat passes from the bead
to the block. Gases that are different to air will affect the rate at which heat transmits from the bead to the block,
these rates of change are measured and displayed as leak rates.
The diagram below shows the basic functionality of the GasCheck G's Thermal Conductivity sensor.
A fan draws a small flow of gas through the probe and into the sensing chamber. The thermistor bead heats up when
electrical power is applied. As air passes through the cell a constant level of heat is transmitted to a Temperature
Stable block through the air, this rate of heat transmission is used to 'Zero' the instrument.
When gases with different thermal qualities pass through the chamber the amount of heat being transmitted to the
Temperature Stable block changes. These changes are measured, calculated and displayed on GasCheck G as leak
rates or gas concentrations.
Some gases have similar thermal properties to that of air, therefore the GasCheck G can
only detect larger concentrations of these gases.
Some gases have positive and other gases negative signals. To simplify the instruments
function GasCheck G only displays changes as positive readings.
The GasCheck G can NOT differentiate between gases, selecting a specific gas on the
GasCheck G allows the instrument to calculate concentrations of that gas only if that gas is
being detected.
Prob
e
Temperature
Stable
Fan
Air flow
Display
Block

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Replacing batteries
Before using the GasCheck G instrument ensure the batteries
are fitted correctly or ensure NiMH (rechargeable) batteries are
fully charged before use.
To fit or replace batteries you must first remove the battery
cover from the rear of the instrument.
This can be done by prising open the battery clip with a finger
nail or screw driver.
Removing the battery cover will reveal a battery holder, which
requires 4 x AA size batteries. Before removing old batteries or
fitting new ones unclip the battery holder from the instrument
by prising apart the PP3 type clip shown in the illustration.
Once the battery holder is disconnected from the instrument,
the batteries can be removed or replaced however care must
be taken when refitting the batteries to ensure they are the
correct polarity, polarity markings are moulded on to the
battery holder plastic.
The battery holder can be reconnected to the GasCheck G by
firmly pressing the two halves of the PP3 clip together. Care
should be taken to ensure the polarity is correct, see the PP3
diagram (right).
The battery pack is then laid within the instrument and the
battery cover refitted, be careful not to trap wires when
refitting the battery cover.
Battery holder
Battery holder
PP3 clip
PP3 clip

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Getting started
The Keypad
All GasCheck G models have the same keypads, the following section explains the general functionality of each key:-
When the GasCheck G first switches on it will display its model number and
the Gas that it has been calibrated with.
A second screen then displays the instrument’s serial number, the
instrument’s firmware version and ION Science web address.
A third screen appears to indicate the GasCheck G is Zeroing it's signal.
Once the Zero routine is complete the instrument displays it's running screen and is ready for use.
ENTER
This key is used to select functions and
accept settings after a parameter has
been adjusted.
ZERO
Pressing the Zero key Zeros-out
background readings.
On/Off.
Press this key once to switch the
instrument 'ON'. To switch the instrument
off press and hold this key until the bar
graph reaches the right side of the screen.
This procedure has been designed to avoid
accidental switch OFF.
ESCAPE
This key is used to return the display to the
previous screen and to abort an
adjustment. Repeated pressing of this key
will return the display to the 'Display
screen'. The 'ESC' key also takes you to the
menu while on the display screen.
UP
Use the UP key to scroll through
the function menu and to adjust
settings.
DOWN
Use to scroll down or change
selection.

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Instrument main menu
Once the GasCheck G has run through its 'Start up' routine it will display its normal 'Running screen' used when
locating gas leaks. Before using the instrument the various settings should be set and adjusted to suit the application.
Pressing the 'Esc' key while viewing this
'Running screen' will access the
instruments Main Menu. Repeated
pressing of the 'Esc' returns back to the
'Running screen'.
Running screen
Main Menu
Contrast
Backlight
Sound
Peak Hold
Calibration
Battery
View Data
Units
Gas
Upgrade
PLEASE NOTE:
The amount of functionality varies
between models. The 'Function' section
of this manual indicates which functions
relate to which model.

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Running screen
GasCheck G displays the 'Running screen' whenever the instrument is being used to detect leaking gas, the illustration
below outlines the various information and icons.
Gas selection
The GasCheck G2 and G3 display the gas being measured in the top left of the running screen. The GasCheck G2 will
display the gas selected at the factory only however the G3 model has a range of gases that can be selected via an
internal gas table.
Sensitivity
GasCheck G has three (3) sensitivity levels, X100 (times one hundred) is most sensitive, X10 (times ten) is mid range and
X1 (times one) is least sensitive. See the sensitivity of various gases on the table under ‘Functions (continues), Gas
Selection’.
Battery status
When the battery symbol is filled in the battery is full, when just an outline the battery is exhausted
Backlight
The backlight symbol shows the status of the backlight even in bright daylight.
Gas measurement
The GasCheck G2 and G3 measure the leak rate of gas leakage in which ever units are selected.
Sound indication
This symbol shows if the sounder is on or off, if the semi circle (on the right) of the symbol is present then the sound is
switched on, if not the sounder is switched off. The beep that occurs with each key press can not be switched off.
Bar graph
The bar graph increases as gas is detected. This graph is not scaled and should be used for indication only.
The GasCheck G1 has no measured units so relies on this bar graph to indicate leakage, when gas is detected and the
bar graph has reached it's maximum level, a different sensitivity level can be selected to give a wider detection range.
Peak hold
When selected, peak hold displays the maximum measurement on the display. Press the ENTER key resets the reading
but also logs the peak reading in memory.
Gas selection
Sensitivity levels
Gas measurement
Bar graph
Battery status
Backlight indicator
Sound indicator
Peak hold indicator

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Functions
The GasCheck G instruments have a variation of functionality, each of the functions listed below has a number to the
right of the heading that indicates which function is included within each model:-
GasCheck G1 = 1, GasCheck G2 = 2, GasCheck G3 = 3.
Contrast
1, 2 & 3
Use this function to adjust the contrast of the GasCheck G' LCD (Liquid Crystal Display).
Significant variations in ambient temperature conditions can cause the display to appear
too dark or feint.
When this function is selected a number will appear to the right of the Contrast symbol as a
percentage, use the Up and Down keys to adjust the display contrast to the desired level.
When satisfied with the desired level selected, press the Esc key to exit to the main menu.
Backlight
1, 2 & 3
The user can select either Backlight On or Backlight Off.
In daylight the user may not be able to determine if the
backlight is On or Off therefore a symbol on the main
running screen shows the status.
When the backlight is 'ON' it significantly reduces battery life.
Backlight OFF = 40hrs of use, Backlight ON = 20hrs of use.
Sound
1, 2 & 3
The GasCheck G has an audible sounder that increases
frequency as detected gas levels increase. This sounder can be
switched On and Off. Use the Up or Down key to move the 'tick'
to the desired position and then press the 'Esc' key to return to
the Main Menu.
An audible 'beep' can also be heard when ever the key pad is pressed, this beep can not be
switched off.
Peak hold
2 & 3
When selected, this function holds the highest detected reading on the display until the
'ENTER' key is pressed.
Select Peak On or Off using the 'Up or Down' key and then
press 'Esc' key to exit to the 'Main menu'.
When using the GasCheck G, press the ENTER key to clear the
held reading.
The reading held on screen will be logged when the 'ENTER' key is pressed.
Calibration
2 & 3
There are two Calibration settings that can be selected;
Factory and Custom. Factory calibration is carried out
shortly after manufacture and cannot be adjusted, however
Custom calibration offers the ability to calibrate the
instrument between annual Factory calibrations. The

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GasCheck G Zero's its reading at switch on, therefore the
Custom calibration routine only has one stage.
Also see the ‘Calibration’ section of this manual.
Battery selection
3
The GasCheck G will operate using AA size batteries in
either Alkaline (non rechargeable) or Nickel Metal
Hydride (Rechargeable).
Select the battery type using the 'Up or Down' key and
then press the 'Esc' key to exit to the Main menu.
Failing to select the correct battery type will not damage the instrument or affect it's ability
to detect gas, however it will cause the battery indicator to read incorrectly.
View Data
3
The GasCheck G instrument has the ability to data log 10 readings within
its internal memory. To store a reading press the 'ENTER' key while on
the main Running screen. When readings are stored in memory a
symbol will appear on the Main viewing screen.
When the memory is full the 'Data' symbol will flash. The stored data in the memory can be
viewed by scrolling through the logged readings using the 'Up and Down' keys. To delete the
stored data press and hold the 'ENTER' key, the 'trash can' symbol will flash, continue holding
the 'ENTER' key until the data is deleted. Press the 'Esc' key to exit to the Main menu.
Units
3
GasCheck G instruments have the capability of displaying detected readings in a variety of
units; ppm, cc/sec, mg/m3and g/yr.
Use the 'Up and Down' keys to select the desired unit and then press the 'Esc' key to exit to
the main menu.
Please note: the Custom Calibration routine automatically selects the type a calibration
depending on this setting. See the ‘Calibration’ section of this manual.
cc/sec = Cubic Centimeters per second offers a volumetric leak rate that directly
measures the volume of a gas escaping from a given point, it is also known as ml/sec
(Millilitres per second). The GasCheck can typically detect Helium leaks down to 0.00005 of
a cubic centimeters per second.
ppm = Parts per million, this unit indicates a concentration but can't be used to quantify
a volume of gas leakage.
mg/m3= Milligrams per meter cubed, like ppm this unit is also concentration so can't be
used to quantify a volume of gas leakage.
g/yr = Grams per year offers an alternative volumetric leak rate that directly measures
the volume of a gas escaping from a given point.
Display
3
GasCheck G instruments have the capability of displaying cc/sec and g/yr readings in either
decimal or exponent form. (Readings in ppm and mg/m3can only be displayed in decimal
form.)
Use the 'Up and Down' keys to select the desired unit. Press the 'Enter' key to display the
next screen. Use the 'Up and Down' keys to select the desired display and then press the

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'Esc' key twice to exit to the main menu.
Gas selection
3
GasCheck G is calibrated using Helium gas at manufacture, however other gases can be
detected and measured using a gas table within the instrument.
Although GasCheck G can't differentiate between gases it can quantify other gases using
response factors stored in its internal gas table. Gas groups 1 2, 3, 4 and 5 offer a generic
sensitivity.
The following list indicates response factors for specific gases however for advice on gases
not listed please contact ION Science Inc for advice.
Name
Abbreviation
Minimum sensitivity
cc/sec (ml/sec)
Minimum sensitivity
cc/sec (ml/sec)
Hydrogen
H2
7.7 E-6 cc/sec
0.0000077 cc/sec
Helium
He
1.0 E-5 cc/sec
0.000010 cc/sec
Refrigerant R12
R12
2.7 E-5 cc/sec
0.000027 cc/sec
Refrigerant R1301
R1301
2.4 E-5 cc/sec
0.000024 cc/sec
Refrigerant R134a
R134a
5.8 E-5 cc/sec
0.000058 cc/sec
Refrigerant R22
R22
2.6 E-5 cc/sec
0.000026 cc/sec
Refrigerant R11
R11
3.2 E-5 cc/sec
0.000032 cc/sec
Sulphur Hexaflouride
SF6
2.2 E-5 cc/sec
0.000022 cc/sec
Carbon dioxide
CO2
4.0 E-5 cc/sec
0.000040 cc/sec
Methane
CH4
2.9 E-5 cc/sec
0.000029 cc/sec
Argon
Ar
3.5 E-5 cc/sec
0.000035 cc/sec
Oxygen
O2
2.9 E-4 cc/sec
0.000290 cc/sec
Refrigerant R502
R502
3.0 E-5 cc/sec
0.000030 cc/sec
Refrigerant R404a
R404a
3.2 E-5 cc/sec
0.000032 cc/sec
Refrigerant R407c
R407c
3.3 E-5 cc/sec
0.000033 cc/sec
Refrigerant R410a
R410a
3.2 E-5 cc/sec
0.000032 cc/sec
Refrigerant R507
R507
3.8 E-5 cc/sec
0.000038 cc/sec
To select an alternative gas use the 'Up and Down' keys to select the desired gas and then
press the 'ENTER' key to confirm the selection, at which point a tick will appear. Press the
'ENTER or Esc' key to exit into the 'Main menu'.
If the gas to be detected does not appear in the instruments internal gas table then one of
the five 'Gas Groups' can be selected. 'Gas Groups' have a variation of sensitivities. (Group 1
being high sensitivity through to Group 5 being low sensitivity) Contact ION Science Inc for
advice.
Gas groups allow the instrument to calculate leak rates with reasonable accuracy.
Upgrade
1 & 2
The GasCheck G instrument can be upgraded using a simple upgrade code.
This facility allows GasCheck G to be upgraded instantly by the user in the field.
The table below shows the various features within each model

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GasCheck G model
Contrast
Backlight
Sound
Peak hold
Custom
Calibration
Battery
Type
Data log
Measurement Units
Gas table
Upgrade
G1
X
X
X
X
G2
X
X
X
X
X
X
G3
X
X
X
X
X
X
X
X
X
To upgrade a GasCheck G simply purchase an upgrade code from ION Science Inc, enter the 12 digit number in the
upgrade screen using the UP, DOWN, ENTER and Esc keys. Once all 12 digits are entered correctly the instrument will
automatically switch off.
When the instrument is switched on the new instrument model number will be displayed.

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Using GasCheck G
The GasCheck G instrument
WARNING: Before switching the GasCheck G on, ensure the ambient air is clean as the instrument automatically Zero's
the sensor at switch on. After the instrument has run through it's start up routine, adjust the instrument settings to
the desired levels. Check the instruments sensitivity using a CalCheck or calibration kit.
Switch the GasCheck G on by pressing the ON/OFF key, after the instrument
has completed its Zero routine it will enter it's normal running screen. (see
right)
Ensure the instrument is on the X100 (times one hundred) range while on the main running screen. Use the UP and
DOWN key to adjust between sensitivity ranges. X100 is most sensitive, X1 is the least sensitive.
Gas leaks tend to occur at pneumatic joints or welded seams, hold the GasCheck G at a 45oangle to the object being
tested and drag the probe along the seam or joint at a rate of approximately 25mm per second.
When a leak is detected the bar graph will start to fill and the frequency of the audio output will increase; this will
decrease as the probe moves away from the leak. Return the probe to the suspected leaking area and move slowly
along the same area until the leak is located. Once located the probe should be held at the leak until the numeric
reading stabilizes.
The bar graph offers a graphical indication only and should not be used to measure a leak; you may find that the graph
completely fills however the numeric reading will continue to increase. Should the instrument detect a leak that is too
large for the range selected the numeric screen will flash and display '99999', use the UP or DOWN keys to adjust the
instrument sensitivity.
Variation in temperature, humidity and background gas may result in a constant level being detected on the
instrument. To reset to Zero, hold the instrument away from the source of leak or contamination and then press the
ZERO key. The instruments display will return to a near zero reading.
The following things will affect the instruments reading:-
* Breath of the instrument user contains both CO2and moisture;
* Barometric air pressure and background temperature;
* Sources of cold and heat.

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Probe options
In some applications the grey probe cover may restrict access to
the area under test, the grey probe cover can be removed by
pulling it off from the instrument . When the grey cover is
removed, great care should be taken when using the
instrument.
NOTE:
* Do not remove the semi transparent probe sleeve,
this sleeve ensure the metal inner probe remains 1 mm
from the surface of the test area avoiding accidental
dirt and moisture ingress.
* Do not touch the probe and especially the brass
sensor housing. Heat from fingers can result in
significant changes in signal causing false readings.
* Avoid placing the probe on wet or dirty surfaces,
blockage of the probe will result in instrument failure.
Some application may require a longer probe to gain access to
pneumatic joints and seams to be tested, the GasCheck G is also
supplied with a 300mm probe that can be changed by the user.
To change probes carefully follow the following steps:-
1. Switch the instrument OFF
2. Remove the outer grey probe cover 
3. Place the box spanner (supplied with the instrument) over the existing probe so the spanner fits over the
brass nut , unscrew the probe counter-clockwise direction. 
4. Withdraw the spanner and probe assembly 
To refit the short or the long probe follow the steps above but in reverse order.
When using the box spanner to tighten the probe nut, ensure the nut is firmly tightened
however do not use additional tools as the tread may become damaged.
Should a probe become blocked, use dry, clean compressed air to blow out the blockage
from the instrument end of the probe. Ensure probe has been removed first.
The instrument has been factory calibrated using the standard short capillary which sets a
certain flow rate into the detector.
The long capillary by nature of its construction has a different flow to improve the time response in detection. This will
change the calibration of the instrument when the long probe is used instead of the short capillary. Thus the long
probe is only to be used in finding leaks in difficult places where the standard short probe cannot reach. The readings
given by the long probe are only qualitative and the reading given by the display is only to be taken as being relative to
another value given by another leak site while using the long probe.
Ensure safety guidelines are adhered to when using compressed air.
(ION Science Inc takes no responsibility for injury or damage caused by misuse of
compressed air equipment)

GasCheck G Instrument User Manual V2.4R
Unrivaled Gas Detection. Page 19 of 26 ionscience.com/usa
Detecting leaks
Over view
Hold the GasCheck G in one hand and draw the
instrument probe along the area to be checked at
approximately 25mm per second. When a leak is
detected retrace the route of the probe at a slower
rate until the leak is located. Once located hold the
instrument over the leak until the measurement
stabilizes. The reading can be logged by pressing the
ENTER key.
Some readings may be larger than the instrument can
detect and the measurement units will be replaced by
'99999' on the display, in which case use the UP or
DOWN keys to adjust the instruments sensitivity.
When detecting very small leaks or when detecting
gasses less sensitive, a rate of 10mm per second may
be required.
The outer grey probe cover can be removed to allow better access to restricted areas, if the outer probe is removed
the following points should be noted:-
•Avoid bending the inner probe as this will affect the GasCheck G's accuracy.
•Avoid placing the probe in liquid or dirt as the probe can become blocked.
•Care should also be taken to ensure the brass sensor housing component remains at a constant temperature.
Avoid touching the brass sensor block with fingers.
•GasCheck G can detect changes in Humidity and Carbon dioxide, therefore avoid breathing on the probe.
•The thin white tube that covers the inner probe should not be removed, this tube ensures a 1mm gap is
maintained between the probe and the surface being tested.

GasCheck G Instrument User Manual V2.4R
Unrivaled Gas Detection. Page 20 of 26 ionscience.com/usa
Calibration
Overview
The GasCheck G has two selectable calibration settings; Factory
and Custom. 'Factory Calibration' is carried out at ION Science
Inc/ Authorized Service Centers during the instruments
manufacture and during annual calibration, it can be selected
and used but can not be changed.
The GasCheck G is calibrated against a 5000 ppm Helium
concentration and a 0.0005cc/sec (5 E-4) Helium leak rate.
'Custom Calibration' gives the user the ability to calibrate the
instrument. This facility may offer improved accuracy over the
'Factory Calibration' if the Barometric air pressure differs from
that stated on the instruments Calibration certificate.
Selecting Factory or Custom Calibration
To select either Factory or Custom Calibration select the Calibration
screen and user the UP and DOWN keys to move the 'tick / check'
under the desired symbol, then Press the 'Esc' key to exit into the
main menu.
'Custom Calibration' can only be selected and use after the instrument has been calibrated by the user, to do this
move the 'tick / check' under the 'Custom Cal' symbol and press the ENTER key.
The GasCheck G requires either 5000 ppm Helium concentration or a 0.0005cc/sec (5 E-4 cc/sec) leak rate as a
reference. The GasCheck G automatically selects the type of Calibration media based on which units the instrument
already has selected.
If the GasCheck G is used to detect leaks measured using 'ppm or mg/m3' units then the instrument must be calibrated
using a 5000 ppm Helium concentration.
If the GasCheck G is used to detect leaks measured using 'cc/sec' units then the instrument must be calibrated using a
0.0005 cc/sec (5 E-4) Helium leak.
Calibration procedure using 'ppm' units
Please read this entire procedure before proceeding with this calibration routine.
1. Fill an empty (uncontaminated) sample bag with 5000 ppm Helium gas before
starting the calibration procedure. Also remove the outer grey probe from the
GasCheck G.
2. Select the 'Custom Cal' symbol from the instruments menu. An option appears
allowing the adjustment of the 'ppm' value to ensure the instrument matches the
gas concentration being used. Use the UP and DOWN keys to adjust between 4900
and 5100 ppm.
3. Ensure the instrument is in clean air and then press the ENTER key, the instrument
will Zero, this will take a few seconds but once complete a 'Ready' message will
appear.
4. Insert the instruments probe fully into the sample bag containing the gas and press
the ENTER key. The instrument will automatically sequence through the cold and
hot stages of calibration but when finished gives a summary of values.
5. Press the ENTER key to return back to the calibration option screen. Press the ESC
key to start using the instrument or press the ENTER key to calibrate again.