Geotech Biogas User manual

Copyright© 2007 BMUK001 / Issue 1
Biogas
Operating Manual
Geotechnical Instruments (UK) Ltd
Sovereign House
Queensway
Leamington Spa
Warwickshire
CV31 3JR
England
Tel: [phone]
Fax: [phone]
Email: [e-mail]
www.geotech.co.uk

Biogas Operating Manual
BMUK0001 / Issue 1 Geotechnical Instruments (UK) Ltd Page 1
TABLE OF CONTENTS
1. INSTRUCTIONS SPECIFIC TO HAZARDOUS AREA INSTALLATIONS ........................................ 3
1.1 SAFETY RELATED INFORMATION INTHIS MANUAL ................................................................................ 3
1.2 SAFETY INFORMATION ............................................................................................................................ 3
2. INTRODUCTION......................................................................................................................................... 4
2.1 MAIN FEATURES OF THE INSTRUMENT ..................................................................................................... 4
2.2 PHYSICAL CHARACTERISTICS OF THE ANALYSER..................................................................................... 4
3. GENERAL OPERATIONAL FEATURES ................................................................................................ 5
3.1 SWITCHING THE INSTRUMENT ONAND OFF............................................................................................. 5
3.2 KEYPAD LOCK.......................................................................................................................................... 5
3.3 WARM-UP SELF TEST............................................................................................................................... 5
3.4 WARNING AND ERROR DISPLAY............................................................................................................... 5
3.5 COLD START ............................................................................................................................................ 6
3.6 STORAGE.................................................................................................................................................. 6
3.7 BATTERY/CHARGING ............................................................................................................................... 7
3.8 MAIN READING SCREEN........................................................................................................................... 7
3.9 MEMORY ................................................................................................................................................. 7
3.10 CLEAR READING MEMORY ...................................................................................................................... 8
3.11 VIEW READINGS....................................................................................................................................... 8
3.12 ADJUST CONTRAST .................................................................................................................................. 8
3.13 INSTRUMENT SETTINGS............................................................................................................................ 8
3.14 SET TIME / DATE...................................................................................................................................... 8
3.15 SET GAS ALARMS .................................................................................................................................... 8
3.16 OPERATING LANGUAGE............................................................................................................................ 9
4. TAKING READINGS................................................................................................................................... 9
4.1 PRELIMINARY CHECKS............................................................................................................................. 9
4.2 TAKING READINGS ................................................................................................................................... 9
4.3 TEMPERATURE PROBE READING............................................................................................................ 11
4.4 EXTERNAL GAS POD READING ............................................................................................................... 11
4.5 ANEMOMETER PROBE READING............................................................................................................. 11
4.6 CROSS-GAS EFFECTS ............................................................................................................................. 12
5. USER CALIBRATION............................................................................................................................... 13
5.1 INTRODUCTION ...................................................................................................................................... 13
5.2 CALIBRATION GASES.............................................................................................................................. 13
5.3 SET-UP................................................................................................................................................... 14
5.4 EQUIPMENT............................................................................................................................................ 14
5.5 GAS ANALYSER...................................................................................................................................... 15
Step 1: Enter Target Concentrations ............................................................................................................ 15
Step 2: Zero CH4 and CO2 channels............................................................................................................ 15
Step 3: Zero O2 channels.............................................................................................................................. 16
Step 4: Span CH4 and CO2 channels ........................................................................................................... 16
Step 5: Span CH4, CO2 and O2 channels .................................................................................................... 16
Step 6: Span O2 channels ............................................................................................................................. 17
5.6 TROUBLE SHOOTING .............................................................................................................................. 17
5.7 FACTORY SETTINGS ............................................................................................................................... 17
5.8 LAST FIELD CALIBRATION...................................................................................................................... 18
6. SERVICE..................................................................................................................................................... 19
7. TECHNICAL SPECIFICATION .............................................................................................................. 20

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8. EC DECLARATION OF CONFORMITY............................................................................................... 22
9. INSTRUCTIONS FOR SAFE USE – ITALIAN LANGUAGE............................................................... 23
9.1 ISTRUZIONI SPECIFICHE PER LE INSTALLAZIONI IN AREE PERICOLOSE...................................................... 23
9.2 INFORMAZIONI DI QUESTO MANUALE RELATIVE ALLA SICUREZZA ........................................................ 23
9.3 INFORMAZIONI SULLA SICUREZZA ......................................................................................................... 24
9.4 VISUALIZZAZIONE DI AVVERTENZE ED ERRORI....................................................................................... 24
9.5 BATTERIA/RICARICA .............................................................................................................................. 24
9.6 LETTURA DEL RILEVATORE DELLA TEMPERATURA ................................................................................. 24
9.7 ACCESSORI CHE NON POSSONO ESSERE USATI IN UN'ATMOSFERA POTENZIALMENTE ESPLOSIVA. ........... 24
9.8 TARATURA............................................................................................................................................. 25
9.9 MANUTENZIONE..................................................................................................................................... 25
9.10 DICHIARAZIONE DI CONFORMITÀ EC...................................................................................................... 26
10. INSTRUCTIONS FOR SAFE USE – GERMAN LANGUAGE ......................................................... 27
10.1 ANWEISUNGEN FÜR INSTALLATIONEN IN GEFAHRENBEREICHEN............................................................ 27
10.2 SICHERHEITSRELEVANTE INFORMATIONEN IN DIESEM HANDBUCH ................................................. 27
10.3 SICHERHEITSINFORMATION .............................................................................................................. 28
10.4 WARN-UND FEHLERANZEIGE ................................................................................................................ 28
10.5 AKKU/LADEVORGANG ........................................................................................................................... 28
10.6 TEMPERATURFÜHLER............................................................................................................................. 28
10.7 ZUBEHÖR,DAS IN EINEM EXPLOSIONSGEFÄHRDETEN BEREICH NICHT EINGESETZT WERDEN DARF......... 29
10.8 KALIBRIERUNG ...................................................................................................................................... 29
10.9 WARTUNG.............................................................................................................................................. 29
10.10 EG-KONFORMITÄTSERKLÄRUNG ....................................................................................................... 30
11. INSTRUCTIONS FOR SAFE USE – FRENCH LANGUAGE........................................................... 31
11.1 INSTRUCTIONS SPECIFIQUES POUR LES INSTALLATIONS DANS DES EMPLACEMENTS DANGEREUX ........... 31
11.2 INFORMATIONS EN MATIERE DE SECURITE CONTENUES DANS LE PRESENT MANUEL ..................... 31
11.3 INFORMATIONS EN MATIERE DE SECURITE ....................................................................................... 32
11.4 AFFICHAGE D’AVERTISSEMENTS ET D’ERREURS..................................................................................... 32
11.5 BATTERIE/MISE EN CHARGE................................................................................................................... 32
11.6 SONDE DE MESURE DE TEMPERATURE.................................................................................................... 32
11.7 ACCESSOIRES NON UTILISABLES EN ATMOSPHERES POTENTIELLEMENT EXPLOSIVES.............................. 32
11.8 ETALONNAGE......................................................................................................................................... 33
11.9 ENTRETIEN............................................................................................................................................. 33
11.10 DECLARATION DE CONFORMITE CE ................................................................................................... 34
12. INSTRUCTIONS FOR SAFE USE – SPANISH LANGUAGE .......................................................... 35
12.1 INSTRUCCIONES ESPECÍFICAS PARA INSTALACIONES EN ÁREAS DE PELIGRO ......................................... 35
12.2 INFORMACIÓN RELACIONADA CON LA SEGURIDAD EN ESTE MANUAL.............................................. 35
12.3 INFORMACIÓN DE SEGURIDAD........................................................................................................... 36
12.4 ADVERTENCIA Y VISUALIZACIÓN DE ERROR ........................................................................................... 36
12.5 BATERÍA/CARGA.................................................................................................................................... 36
12.6 LECTURA DE LA SONDA DE TEMPERATURA............................................................................................. 36
12.7 ACCESORIOS QUE NO PUEDEN UTILIZARSE EN UNA ATMÓSFERA POTENCIALMENTE EXPLOSIVA.............. 36
12.8 CALIBRACIÓN......................................................................................................................................... 37
12.9 REVISIÓN ............................................................................................................................................... 37
12.10 DECLARACIÓN DE CONFORMIDAD CE................................................................................................ 38
13. AN IMPORTANT NOTICE TO ALL OUR CUSTOMERS............................................................... 39

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1. Instructions Specific to Hazardous Area Installations
(Reference European ATEX Directive 94/9/EC, Annex II, 1.0.6.)
The following instructions apply to equipment covered by certificate numbers Sira 06ATEX2202X:
•The equipment may be used with flammable gases and vapours with apparatus group IIA and
temperature class T1
•The equipment is only certified for use in ambient temperatures in the range 0ºCto +40ºCand
should not be used outside this range
•Installation shall be carried out in accordance with the applicable code of practice by suitably
trained personnel
•Repair of this equipment shall be carried out in accordance with the applicable code of practice.
•The manufacturer will specify those materials which are important to the type of protection.
•When the Biogas instrument is in the hazardous area it shall only be externally attached via
connector A to devices that are marked with the certificate number Sira 06ATEX2202X.
•If the equipment is likely to come into contact with aggressive substances, e.g. acidic liquids or
gases that may attack metals, or solvents that may affect polymeric materials, then it is the
responsibility of the user to take suitable precautions, e.g. regular checks as part of routine
inspections or establishing from the material’s data sheet that it is resistant to specific chemicals
that prevent it from being adversely affected, thus ensuring that the type of protection is not
compromised.
The Biogas has been certified to Hazardous Area Classification
II2G EEx ibd IIA T1 (Ta = 0ºC to +40ºC)
It is vital the instructions in this manual are followed closely.
It is the responsibility of the operator to determine the protection concept and classification required for
aparticular application.
1.1 Safety Related Information In This Manual
Information in this manual that may affect the safety of users and others is preceded by the following
symbol: Warning.
Failure to follow this information may result in physical injury which in some cases could be fatal.
1.2 Safety Information
Warning The Biogas can be used for measuring gases from landfill sites and other
sources as described in this manual. Inhaling these gases may be harmful to
health and in some cases may be fatal. It is the responsibility of the user to ensure
that he/she is adequately trained in the safety aspects of the gases being used
and appropriate procedures are followed. In particular, where hazardous gases
are being used the gas exhausted from the analyser must be piped to an area
where it is safe to discharge the gas. Hazardous gas can also be expelled from the
instrument when purging with clean air.

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2. Introduction
This manual explains how to use the Biogas range of instruments.
Note The Geotechnical Instruments range of gas analysers are sensitive pieces of
scientific equipment, and should be treated as such.
2.1 Main features of the Instrument
Measurement of the following gases:
•Methane and Carbon Dioxide by Infra-Red Absorption
•Oxygen by chemical cell
•Other gases possible by way of external gas pods - contact supplier
•Measurement of system pressure
•Measurement of barometric pressure
•Measurement of gas flow by use of Anemometer, orifice plate, or pitot tube.
•Measurement of Static and Differential pressures.
2.2 Physical Characteristics of the Analyser

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3. General Operational Features
3.1 Switching the Instrument On And Off
When switching the instrument on a long beep will be emitted followed by the Geotechnical
Instruments (UK) Ltd logo being displayed along with the product name. A power-on self-test will then
commence. Assuming there are no warnings to display the instrument will continue to the main gas
reading screen.
When switching the analyser off, the on/off button must be held down for approximately 1.5 seconds,
at which point a clean air purge will be carried out. If for any reason the analyser ‘locks-up’ and will not
switch off in this manner, press and hold the on/off button for 15 seconds; this will force the instrument
to switch off.
3.2 Keypad lock
The keypad can be locked by pressing and holding the ‘backlight’ key for 2 seconds. This will avoid
accidental key presses when carrying the analyser between sample points. Press and hold again to
unlock the keypad.
3.3 Warm-up Self Test
When switched on the instrument will perform a pre-determined self-test sequence taking
approximately 30-40 seconds. During this time many of the analyser’s functions are tested, including:
•General operation
•Pump function
•Gas flow measurement
•Calibration
•Backlight function
•Solenoid function
During the self-test the following information is also displayed:
•Manufacturer’s service due date
•The last gas check date
•Software version
•Date format
•Serial number
•Operating language
•Baud rate
3.4 Warning and Error Display
During the self-test, if any operational parameters are out of specification or the pre-programmed
recommended calibration/service date has passed, various errors or warnings may be displayed. Only
three warnings/errors can be displayed at any time, use the cursor keys to scroll through the list.
Warnings Displayed
All warnings displayed will be prefixed by the word ‘WARNING‘ followed by a relevant description.
There are two types of warning that may be displayed, firstly the general warnings that may not affect
the instrument’s function and those where the self-test has detected a function that is outside the usual
programmed operating criteria, e.g. battery charge low, memory nearly full. The second being
operational parameters that could affect the performance of the analyser: CH4out of calibration, CO2
out of calibration.

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The most likely reason for the errors is either an incorrect user calibration, or sensor failure. If an
incorrect user calibration has caused the warning it should be correctable by way of returning the
instrument to factory settings, zeroing or carrying out a user calibration as necessary for the relevant
function.
Errors Displayed
All errors displayed will be prefixed by the word ‘ERROR‘ followed by a error code. The errors detected
by the self-test are usually caused by a user calibration being out of specification or possible memory
corruption and will affect the instrument’s function and should therefore be corrected before use, e.g.
01-User cal data, CH4reading out of specification, 02-User cal data, CO2reading out of specification,
04-User cal data.
Note If any other types of warning or error are displayed it is advisable to contact
Geotechnical Instruments (UK) Ltd for further information.
Under and Over Range Codes
If a reading is under range (ie below zero) it will be displayed with ‘less than’ chevrons (<<.<). This can
occur if a channel has been incorrectly calibrated or has exceeded it’s specified range. If a reading is
over range (ie above the maximum allowed reading) it will be displayed with ‘more than’ chevrons
(>>.>).
Anumber displayed as ‘**.*’ indicates an error, usually where the instrument has been unable to
complete a particular calculation. Where there is no data is available dashes (--.-) are displayed. This
usually occurs when a particular reading or parameter has been skipped by the user.
3.5 Cold Start
Note This function should only be used as a last resort. For gas calibration error
messages ensure a factory setting and user calibration has been carried out first.
Acold start should only be carried out if no other course of action has proved successful, as this
function will clear the instrument memory entirely, reset all factory settings and reset the internal time
and date to a default setting.
To carry out a cold start, switch the instrument ON and during the self-test press and continue to hold
the enter key until such time as the self-test has been completed. Upon completion of the self-test
a‘Pass-code Entry’ screen will be displayed. At this point the key may be released. Input the code
‘12345’ and press to confirm. After the pass-code has been accepted the instrument’s serial
number will be displayed along with the hours of operation and two options:
•1-Cold Start
•0-Exit
Only select option if a cold start is to be carried out. After selection, key will require pressing
again to confirm this operation. The cold start menu will be displayed again; press key ‘0’ to continue
with normal operation.
3.6 Storage
The instrument should not be exposed to extremes of temperature. Do not keep the instrument in a hot
vehicle. When not in use instruments should be kept in a clean, warm and dry environment, such as an
office. The instrument should be discharged and fully charged at least once every four weeks,
regardless of indicated charge state.

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3.7 Battery/Charging
Warning The battery charger is NOT covered by the Ex certification. The battery must be
charged only in a safe area.
The battery used in the Biogas instrument is Nickel Metal Hydride and manufactured as an
encapsulated pack from six individual cells. This type of battery is not as susceptible to the top-up
charging ‘memory effects’ as Nickel Cadmium batteries, although it is not recommended that the unit
be given small top-up charges. The charger should only be disconnected when ‘charged’ is indicated.
The battery charger is intelligent and will indicate when the unit is charging, charged or if there is a
fault. A full charge should take approximately two hours.
3.8 Main Reading Screen
The main reading screen is also considered to be the normal operation screen and most operations
are carried out from this starting point. All of the instrument readings are displayed in this screen. Most
other operations can be selected via the main menu, key in this screen. Whenever a key is pressed
the unit will emit a short ‘beep’ as an acknowledgement. This function cannot be turned off.
3.9 Memory
The analyser's memory is volatile, although it is retained by a battery back-up system.
The memory is not to be used as a permanent storage medium and any data should be transferred to
amore permanent storage medium as soon as possible. An analyser should never be stored for
prolonged periods with valuable data in its memory.
Although unlikely, sudden shocks, high levels of electromagnetic interference or static discharge may
cause memory corruption or loss. If this occurs the memory should be cleared and the calibration re-
set to factory settings before further use.

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3.10 Clear Reading Memory
Selected via the main menu the clear memory screen enables the user to check how many readings
have previously been taken and clear them if necessary. Clearing readings is a simple process just
follow the on-screen instructions. Before readings are actually deleted a caution is displayed as once
readings have been deleted they cannot be recovered. The Biogas instrument can store up to 100
readings. Once the reading memory is full it is not possible to store any more readings. When the
store key is pressed the instrument will show a brief message stating that the memory is full.
3.11 View Readings
Stored readings can be viewed via the main menu. The cursor keys can be used to scroll through
the available readings either forwards or backwards. One complete reading is displayed on each page
using a similar layout to the main reading screen.
3.12 Adjust Contrast
The Biogas instrument automatically adjusts the screen contrast to maintain a normal viewing
contrast according to the current display temperature. Manual adjustment of the contrast is also
available and can be carried out with using the cursor keys. The manually set contrast setting is
retained when the read-out is switched off and therefore may require re-setting when next switched on.
3.13 Instrument Settings
The instrument settings screen allows the user to configure the reading sequence and various other
options as desired. When selected the current settings are displayed. These include the following
parameters:
•Purge Time
•Prompt for ID reading
•Prompt for temperature reading
•Flow device
•Pipe and Orifice diameters
•Units of measurement
Pressing the key brings up a sub-menu where you can select the parameter to be edited. Most of
the parameters are self-explanatory. There are limits on the size of pipe and orifice diameters. These
can be affected by the units of measurement currently selected. Also, the ratio of the orifice to pipe
diameter cannot exceed 75% and the orifice cannot be larger than the pipe diameter.
3.14 Set Time / Date
Selected via the main menu the set time/date screen enables the user to check or set the internal
clock. This value is appended to every stored reading. It is also displayed in the top-left corner of the
main read screen. Setting the clock is a simple process - just follow the on-screen instructions. It is
also possible to switch the date format between dd/mm/yy and mm/dd/yy formats if required. Please
note the clock will need to be manually adjusted to cope with daylight saving changes or changes when
crossing time zones.
3.15 Set Gas Alarms
The Biogas instrument has the facility to set rising or falling alarms for the three main gas channels
(CH4,CO2and O2). Once enabled these alarms become active in the main reading screen. If an alarm
is triggered a flashing bell symbol is displayed next to the appropriate gas value and a beeper is
sounded until the gas level has dropped below the trigger point.

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3.16 Operating Language
The Biogas instrument has the facility to select from the following operating languages: English,
German, French, Italian and Spanish. Due to the nature of the various languages the screen layout
may change slightly, although the functionality will always remain the same.
4. Taking Readings
Warning Inhaling hydrogen sulphide gas can cause death. It is the responsibility of the user
to ensure that he/she is adequately trained in the safety aspects of using H2S. In
particular, where hazardous gases are being used the gas exhausted from the
analyser must be piped to an area where it is safe to discharge the gas.
Hazardous gas can also be expelled from the instrument when purging with clean
air.
4.1 Preliminary Checks
Prior to going to site, it is good practice to ensure:
•The instruments time and date are correct.
•The water trap has a clean and dry filter fitted.
•The inlet port micro-fibre filter is clean and dry.
•Asupply of spare filters is available in case of accidental water blockage or contamination
•The battery has a good charge (minimum 25% charge, even if only a few readings are required)
•The memory has sufficient space available.
•The main gases have been auto-zeroed, without gas concentration present.
•If necessary, check the span calibration with a known concentration calibration-check gas.
DO’s
•Travel to site with the instrument in the vehicle's interior - not in the boot, where it may be
subjected to extremes of temperature and possible shock damage.
•Protect the instrument from strong direct sunlight which will quickly raise the temperature of the
instrument beyond its operating range and the LCD display will appear almost black and the
contrast setting cannot alter the contrast.
•Remember always use the water trap! If the water trap becomes flooded, change the filter and
ensure all tubes are clear before re-use.
DONT’s
•Do not place the instrument against anything hot (e.g., gas extraction pipe or car body) or in an
unattended car during the summer) as this will cause excessive internal temperatures which may
cause erroneous readings.
•Get the the instrument wet, for example exposure to heavy rain.
4.2 Taking Readings
Depending on the user settings the exact reading procedure can change. The following method is
considered best practice and when followed correctly will allow quick and consistent readings to be
recorded. There are essentially two stages which enable a complete reading to be stored. Firstly, the
main gases are recorded which need to be fixed before a flow reading can be taken.
1. When the instrument is first switched on it should be purged with fresh air and allowed to stabilise
for a few minutes. At this point it is good practice to zero all channels and devices to be used.
These options are available via the main menu. You should now be ready to take your first reading.

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You can do this by pressing key to re-set the reading procedure or by pressing store reading.
Either option allows a new reading sequence to begin.
2. At this point connect the sample tube (with water trap) from the sample point to the inlet port of the
instrument, ensuring the connector ‘clicks’ into place. If using a gas pod, it should plugged-in to
external port 1 and connected to the outlet of the instrument. At this point you will see the system
pressure reading change as it responds to the pressure on the inlet hose. It is important to
remember that the system pressure reading is only active during this initial phase. After the pump
is activated or if the user presses measure flow or store reading the system pressure is
frozen until the next reading cycle has begun.
3. Pressing the pump key draws a gas sample into the instrument. You should see the main gas
readings start to change. It is recommended to run the pump until the gas readings have stabilised
(typically 30 seconds) using the counter provided. If you are only interested in the main gases
pressing the store key now would record these values and re-start the reading cycle. Note…If
you have enabled gas alarms a flashing bell symbol may be displayed next to the appropriate gas
reading value if a pre-set alarm condition has been passed.
4. Assuming you have selected a flow device (via instrument settings) press key to take a flow
reading. At this point you should see a brief message confirming that the gas readings have been
fixed (i.e. stored temporarily). Depending on which flow device you have selected the operation
may vary. For example if you have no flow device selected then you will not have a key option,
pressing the store key will store the currently displayed data to memory.
5. If enabled (via instrument settings) you will be prompted to enter a temperature reading or attach a
temperature probe. If you are not using an external gas pod you might want to disable this option.
You can then plug a temperature probe in to external port 1 (in place of the gas pod) at the start of
the reading cycle. The temperature reading is then displayed on the main gas screen and will be
frozen when key is pressed to start the flow measurement phase. Otherwise simply follow the
on-screen instructions to record a valid temperature reading either by attaching a probe or
manually entering the temperature recorded using a third party sensor. If no temperature is
available then 20 degrees centigrade is assumed for the subsequent flow calculations.
6. If you have selected either pitot tube or orifice plate as your device type you will now be asked to
zero the static and differential pressure transducers. It is possible to skip this stage but it is
important to zero the transducers for repeatable results especially on very low flows. To zero the
transducers simply follow the on-screen instructions. Remember you will have to disconnect the
hoses from the sample point and wait a few seconds for the readings to stabilise before zeroing.
You will then be returned to the main read screen where the flow calculation will be displayed along
with the current static and differential pressures. You will also be able to review the Orifice and
pipe diameter that are currently selected. These can be changed (via instrument settings) if
required. Once the flow reading has stabilised simply press store to record the reading.
7. If you have selected an anemometer as your device type there is no need to zero the transducers
and this stage is skipped automatically. You be returned directly to the main read screen where the
velocity and flow will be displayed along with the currently selected pipe diameter (required for a
valid flow calculation). The anemometer should be plugged into external port 2 on the instrument.
After it has been correctly inserted into the sample point, allow the flow reading to stabilise and
press store to record the reading.
8. If you have selected user input as your device type you will be prompted to enter a flow reading
manually. After typing in the flow reading you can return to the main reading screen and the flow
measurement you entered will be displayed. Press store to complete the reading.
9. After the store key is pressed and if enabled (via instrument settings) you will be prompted to
enter an 8 character identification code for the current reading set. This is done by using the
cursor keys to navigate around a grid of alphanumeric characters. The enter key is used to
select each character as required. Key is used complete the process and exit this screen. At
anytime the backspace key can be used to erase any selected characters if required.

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10. After each reading the instrument is automatically purged. You will be prompted to disconnect all
hoses from the instrument before the purge begins. The purge time can be varied but a minimum
of 30 seconds is recommended. You should be looking for the gas readings to return to nominal
values for fresh air. You may want to reconnect the gas pod at this stage to ensure that this also
receives a purge. Of course an additional purge could also be performed manually if required. After
the purge has completed you will be prompted to re-attach your hoses ready for the next reading.
Depending on the user settings and accessories used the following will be stored for each reading:
•ID code
•Current time / date
•Main gas readings and balance (CH4,CO2, O2)
•LEL CH4
•Barometric pressure
•System pressure
•Static pressure
•Differential pressure
•Temperature
•Flow [including device type, orifice diameter and pipe diameter where applicable]
•Anemometer
•External gas pod
When the analyser is switched off a clean air purge is automatically started for a pre-determined time.
This ensures that the analyser is free from gas and ready for the next measurement. This final purge is
especially important for the oxygen sensor and external gas pod sensor as it will continue to degrade if
stored whilst contaminated with gas.
4.3 Temperature Probe Reading
The Biogas instrument has the facility to automatically display and record the borehole temperature
via an optional temperature probe. When a temperature probe is fitted to external port 1 (RS232 port),
the temperature will be displayed in the main reading screen and recorded with all other data. The
operation of the temperature probe will differ slightly depending on what instrument settings have been
selected.
Please note…The temperature probe is part of the Biogas Ex certification and is therefore certified
for use under the same conditions as the analyser.
4.4 External Gas pod Reading
The Biogas instrument can read external gas pods. When a gas pod is fitted to external port 1
(RS232 port), the gas type and reading will be displayed in the main reading screen and recorded with
all other data. Although the temperature probe and gas pod use the same port it is possible to read
both by configuring the instrument to prompt for a temperature reading. This way the gas pod can be
used when drawing in a gas sample. The instrument will prompt you to swap the devices at the
appropriate point in the reading sequence. External gas pods can be user calibrated (via the gas
calibration screen) for both zero and span.
Please note…The gas pod is NOT part of the analyser Ex certification and is therefore NOT certified
for use in potentially explosive atmospheres.
4.5 Anemometer Probe Reading
When an anemometer probe is fitted to the analyser’s external port 2 (charger socket), if configured
correctly the flow will be displayed in the ‘Read Gas Levels’ screen and recorded with all other data.

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The Anemometer reads in both velocity and flow rate. In order to calculate the volume flow rate the
pipe diameter will need to be entered into the instrument via the instrument settings screen. The
anemometer can be zeroed via the gas calibration screen.
Please Note…The anemometer probe is NOT part of the analyser Ex certification and is therefore
NOT certified for use in a potentially explosive atmosphere.
4.6 Cross-Gas Effects
Methane, Carbon Dioxide and Oxygen
Methane is measured using dual beam infra-red absorption. Your instrument is calibrated using
certified methane mixtures and will give correct readings provided there are no other hydrocarbon
gasses present within the sample (e.g. ethane, propane, butane, etc.). If there are other hydrocarbons
present, the methane reading will be higher (never lower) than the actual methane concentration being
monitored.
The extent to which the methane reading is affected depends upon the concentration of the methane in
the sample and the concentration of the other hydrocarbons. The effect is totally non-linear and
difficult to predict.
Carbon Dioxide is measured by infra-red absorption at a wavelength specific to carbon dioxide.
Therefore, the carbon dioxide reading will not be affected by any other gases usually found on landfill
sites.
The infrared sensors will not be "poisoned" by other hydrocarbons and will revert to normal operation
as soon as the gas sample has been ‘purged’.
The oxygen sensor is a galvanic cell type and suffers virtually no influence from CO2,CO, H2S, NO2,
SO2or H2,unlike many other types of oxygen cell.
H2SMeasurement
H2Smeasurement via the external gas pod could be affected by other gases. The main cross gas
effects are:
•SO2:20% effect
•NO2:20% effect
Other cross sensitivities are possible. If you suspect a cross sensitivity problem please contact you
supplier for additional information.

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5. User Calibration
5.1 Introduction
The Geotechnical Instruments range of Gas Analysers are calibrated during manufacture and when
returned for service. However, to improve accuracy between services a user calibration can be
performed. Only the three main gases CH4,CO2and O2may be user calibrated.
This section sets out the correct procedures to achieve an accuracy user calibration.
If this calibration is completed incorrectly it may decrease the accuracy of the Gas Analyser.
Two important terms that are used within this section are “Zero” and “Span”.
Zero: The point at which the Gas Analyser is calibrated when there is none of the target gas present.
Span: The point at which the Gas Analyser is calibrated when a known quantity of the target gas is
present.
5.2 Calibration Gases
User calibration of a Gas Analyser will improve the data accuracy in the range of the calibration gases
used. This may cause less accurate readings of concentrations outside this calibrated range. Users
should select the correct calibration gas for the expected gas levels on their particular application.
•To improve calibration at lower levels requires the use of gas mixtures 1 and 2.
•To improve higher levels use gas mixture 3.
Calibration gas CH4CO2O2
Mixture 1 5% 5% 6%
Mixture 2 5% 10% 0%
Mixture 3 60% 40% 0%
These are for general use but other gas concentrations can be used.
Only use gases with a known certified concentration.
Note: The above gases and most other gas concentrations can be supplied by Geotechnical
Instruments (UK) Ltd.
Warning For each gas used the appropriate material safety data sheet must be
read and understood before proceeding. Calibration gases can be
dangerous.

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5.3 Set-Up
Important Do NOT attach the gas supply to the instrument before putting it into
the “Field Calibration Screen” by selecting ‘FIELD CALIBRATION’ from
the main menu.
Calibration
Gas
Canister
Flow
Regulator
Outlet
Exhaust
Outlet
Exhaust
The regulator’s flow is factory set. It only requires a few turns to open, but no adjustment is necessary.
Warning Exhaust port
When the Gas Analyser is being calibrated, there are two possible
exits for the gas, via the usual manner out of the exhaust port of the
analyser or in cases of over-pressurisation the 1/16”port on the
pressure relief valve.
It is recommended that both ports have exhaust tubing attached.
The exhaust tubing must emerge in a well-vented area. Ensure there
are no leaks in the tubing and connections.
The calibration of the Gas Analyser should be carried out in a safe
area with all necessary precautions taken when using potentially
dangerous, explosive or toxic gases.
For each gas used the appropriate material data sheet should be read
and understood before proceeding.
5.4 Equipment
Calibration gas mixtures as specified as above in 58 litre gas canisters.
The regulator supplied by Geotechnical Instruments is recommended as flow and pressure rates are
factory set.

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5.5 Gas Analyser
To achieve the processes set out below choose “Field Calibration” from the Biogas menu.
The first screen to appear (“Check Calibration”) provides the option of checking the gas channels
against known calibration gases before proceeding to re-calibration. Ensure the unit is stabilised at its
working temperature before performing any of the calibration operations.
Readings on the line “a” are the current readings for the channels listed. The figures displayed in line
“b” are the span targets i.e. the concentrations of the calibration gases to be used.
Please note: Depending on the configuration certain gas channels may not be active and will be shown
as “N/A”.
Step 1: Enter Target Concentrations
DO NOT CONNECT CALIBRATION GAS YET.
Enter the certified concentrations of your calibration gases. For two-gas mixtures that contain 0.0% O2,
enter the certified O2 value at 20.9%. For three-gas mixtures with an O2 component enter the O2
certified concentration.
•Press to Edit target concentrations.
•Select CH4from the menu using and enter the certified CH4concentration. Then press .
•Press to Edit target concentrations.
•Select CO2from the menu using and enter the certified CO2concentration. Then press .
•Press to Edit target concentrations.
•Select O2from the menu using and enter the certified CO2concentration or 20.9% for air
calibration. Then press .
Step 2: Zero CH4 and CO2 channels
•Press allow the pump to run for approximately two minutes or until reading stabilises; this
purges the unit of gas.
•Press to switch off the pump.
•Press to select “Calibration Menu”.

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•Press to select “Zero Channel(s)”.
•Press to select “Zero CH4”.
•“USER ZERO COMPLETE.” should be displayed.
•Repeat for other channels if required (except O2)
Step 3: Zero O2 channels
•Attach the calibration equipment as pictured above with gas mixture 2 and turn on gas at regulator.
Do not run the pump.
•Allow the gas to flow through the unit for approximately two minutes or until reading stabilises.
•Press to select “Calibration Menu”.
•Press to select ”Zero Channel(s)”.
•Scroll to “ZERO O2”.
•Press to select “Zero O2”.
•“USER ZERO COMPLETE.” should be displayed.
Step 4: Span CH4 and CO2 channels
Use Step 5 instead, when a 3 gas calibration mixture is available.
•Continue to flow calibration gas or if the zero O2 step has not been required attach the calibration
equipment as pictured above and turn on gas at regulator. Do not run the pump.
•Allow the gas to flow through the unit for approximately two minutes or until reading stabilises.
•Press to select “Calibration Menu”.
•Scroll to “SPAN CHANNEL(S)”.
•Press to select “SPAN CHANNEL(S)”.
•Scroll to “SPAN CH4@05.0%” (the value set previously).
•Press to select “SPAN CH4@05.0%”
•“CALIBRATION COMPLETE” should be displayed.
Repeat for CO2:
•Press to select “Calibration Menu”.
•Scroll to “SPAN CHANNEL(S)”.
•Press to select “SPAN CHANNEL(S)”.
•Scroll to “SPAN CO2@05.0%” (the value set previously).
•Press to select “SPAN CO2@05.0%”
•“CALIBRATION COMPLETE” should be displayed.
Go to step 6.
Step 5: Span CH4, CO2 and O2 channels
Alternative to Step 4 when a 3 component gas is available
Multi-gas option requires a mix with components of CH4,CO2 and O2, eg 40% CH4, 50%CO2, 10%
O2.
•Press to select “Calibration Menu”.
•Scroll to “SPAN CHANNEL(S)”.
•Press to select “SPAN CHANNEL(S)”.
•Scroll to “SPAN MULTI-GAS”
•Press to select “SPAN CO2@05.0%”
•“CALIBRATION COMPLETE” should be displayed.

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Step 6: Span O2 channels
Alternative to Step 4 when a 3 component gas is available
Multi-gas option requires a mix with components of CH4,CO2 and O2, eg 40% CH4, 50%CO2, 10%
O2.
•Press to select “Calibration Menu”.
•Scroll to “SPAN CHANNEL(S)”.
•Press to select “SPAN CHANNEL(S)”.
•Scroll to “SPAN O2 @ 20.9%” and press to select.
•“CALIBRATION COMPLETE” should be displayed.
5.6 Trouble Shooting
Error message Remedy
“User Zero failed” Apossible reason for this is because the instrument is trying to zero to a
level which is outside the pre-determined range set when the unit was first
calibrated at the factory. To rectify this, first ensure the unit contains
absolutely none of the gas which is being zeroed. For all but O2(which
requires O2free gas) run the pump to purge with fresh air and repeat the
zeroing process. If it will not zero, then refer to the instructions given in the
‘Factory Settings’ section. If the Gas Analyser continues to fail in zeroing then
the unit must be returned to Geotechnical Instruments (UK) Ltd for
investigation.
“Calibration failed” Check the span is set to the correct value, if not, correct and retry spanning
the channel. Repeat the entire procedure, including zeroing the channel and
then calibrate the span. Ensure the reading is stable before spanning the
channel. This message may also appear if attempting to use the ‘Span Multi
Gas’ option when not using a gas containing concentrations of CH4,CO2and
O2.
5.7 Factory Settings
This option will reset the instrument to all of its factory programmed characteristics and will clear ALL
the user defined calibration points.
If in any doubt contact Geotechnical Instruments (UK) Ltd.
From the main “CHECK CALIBRATION” screen:
•Press to enter the calibration menu.
•Scroll to “FACTORY SETTINGS”.
•Press to Select “FACTORY SETTINGS”.
•Two messages will follow, “Resetting please wait.” and “Factory settings restored.”

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5.8 Last Field Calibration
This option can be found in the calibration menu of the ‘field calibration’ section. When selected, this
option will display the time and date that the last field calibration was perfomed on the insturment. It is
also available in the instrument information screen.

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6. Service
Your Biogas instrument should be regularly serviced to ensure correct and accurate operation.
Geotechnical Instruments recommends a service and recalibration every 6 months.
The Biogas instrument is ATEX certified for use in potentially explosive areas. As such it should be
serviced only by qualified engineers. Failure to observe this will result in the warranty becoming invalid
and could invalidate the ATEX certification.
Warning If the Biogas instrument is serviced by unqualified engineers the ATEX
certification may be invalidated and the instrument may be unsafe for use in a
potentially explosive atmosphere.
User serviceable parts
There are no user serviceable parts inside the instrument. Please do not attempt repair as this may
invalidate any warranty supplied with your instrument.
The following parts are supplied by Geotechnical Instruments and can be user serviced:
In line water filter This should be regularly inspected for obstructions or damage and
changed if needed. The instrument should never be operated without the
in line water filter as this may result in water entering the instrument.
Particulate filter The particulate filter is located on the underside of the instrument and is
accessed by removing the plastic plug. This can be removed by
unscrewing using a suitable sized coin. The filter should be replaced if it
is contaminated. Never operate the instrument without the particulate
filter. When replacing the plug be sure not to over tighten it - finger tight
is adequate.
Sample tubing Always ensure that sample tubes are not contaminated or damaged.
QRC connectors Periodically check that the O-rings on the QRC gas connectors are not
damaged. A damaged O-ring can let air into the sample gas and result in
incorrect readings. If the O-ring is damaged the complete QRC
connector should be replaced.