Cosa 9610 User manual

INSTALLATION, OPERATION
AND
MAINTENANCE MANUAL
COSA 9610™
GENERAL PURPOSE & EXPLOSION PROOF
Version: 1.3.3
Software version: 2.3.0.0
Revision date: August 17, 2009
Print date: 08/17/09

INSTALLATION, OPERATION AND MAINTENANCE MANUAL – COSA 9610™
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CAL.xx.x.xxxx
COSA INSTRUMENT CORPORATION
New Jersey Sales Office: Texas Sales & Service Offices:
55 Oak Street 7125 North Loop East
Norwood, NJ 07648 Houston, TX 77028
Tel: [phone] Tel: [phone]
Fax: [phone] Fax: [phone]
New York Corporate &
Manufacturing Offices: E-mail:
84G Horseblock Rd. [email protected]
Yaphank, NY 11980
Tel: [phone] http://www.cosa-instrument.com
Fax: [phone]
Copyright © 2009
All rights reserved.
The contents of this publication are presented for informational purposes only. While every effort has been
made to ensure this document error-free, it should not be construed as warranties or guarantees,
expressed or implied, regarding the product or services described herein or its use or applicability.
COSA Instrument Corporation reserves the right to revise or to improve the design or specifications of the
COSA 9610™ at any time and without notice.

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Table of Contents
1. INTRODUCTION................................................................5
1.1. INTRODUCTION ...............................................................................5
1.1.1. Purpose of the analyzer..........................................................................5
1.2. THE COSA 9610™ ANALYZER............................................................5
1.2.1. Oven with oxygen sensor........................................................................6
1.2.2. The sample system (SCS).......................................................................7
1.3. CALIBRATION PROCEDURE..................................................................8
1.4. EXTENDED (DUAL)RANGE OPTION .....................................................10
1.4.1. Operation............................................................................................10
1.5. SPECIFICATIONS COSA 9610™ WOBBE INDEX ANALYZER ........................11
1.5.1. Analyzer performance...........................................................................11
1.5.2. Utilities................................................................................................11
1.5.3. Installation..........................................................................................11
2. INSTALLATION................................................................ 12
2.1. GENERAL.....................................................................................12
2.2. STORAGE.....................................................................................12
2.3. PLACEMENT..................................................................................12
2.3.1. General...............................................................................................12
2.3.2. COSA 9610™ in general purpose execution (Type 01 & 02).....................13
2.3.3. COSA 9610™ in explosion proof execution (Type 01-Ex & 02-Ex).............13
2.4. MECHANICAL CONNECTIONS..............................................................14
2.4.1. General...............................................................................................14
2.4.2. Sample supply .....................................................................................15
2.4.3. Calibration gasses................................................................................15
2.5. ELECTRICAL CONNECTIONS...............................................................16
2.5.1. COSA 9610™ in general purpose execution............................................16
2.5.2. COSA 9610™ in explosion proof execution .............................................16
3. IN OPERATION................................................................ 18
3.1. START-UP SAMPLE CONDITIONING SYSTEM...........................................18
3.1.1. Inspection, visual and external connections............................................18
3.1.2. Air orifice selection...............................................................................18
3.1.3. Opening of shut-off valves....................................................................19
3.1.4. Setting of gas pressure reducer.............................................................19
3.1.5. Adjusting flow with flow meters ............................................................19
3.1.6. Adjusting booster relays .......................................................................19
3.2. START-UP OF THE CONTROL UNIT ......................................................21
3.2.1. Description..........................................................................................21

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3.2.2. Programming the measurement parameters...........................................21
3.2.3. Main screen.........................................................................................21
3.3. PROGRAMMING MENUS....................................................................27
3.3.1. Calibration Menu..................................................................................27
3.3.2. Operation Menu...................................................................................28
3.3.3. Measurement Menu..............................................................................29
3.3.4. Output Menu .......................................................................................30
3.3.5. Communications Menu .........................................................................31
3.3.6. System Menu.......................................................................................32
3.3.7. Display Menu.......................................................................................33
3.3.8. Reset Alarms Menu ..............................................................................34
3.4. TEMPERATURE CONTROLLED OVEN......................................................35
3.4.1. Furnace temperature control unit ..........................................................35
3.4.2. Adjustment procedure temperature regulator.........................................36
4. PREVENTIVE MAINTENANCE ............................................ 37
4.1. WEEKLY /MONTHLY MAINTENANCE ....................................................37
4.1.1. Compressor (optional)............................. Error! Bookmark not defined.
4.1.2. Filters .................................................... Error! Bookmark not defined.
4.2. THTREE (3) MONTH MAINTENANCE......... ERROR!BOOKMARK NOT DEFINED.
4.2.1. Compressor (optional)............................. Error! Bookmark not defined.
4.3. ANNUAL MAINTENANCE....................................................................38
4.4. TROUBLESHOOTING........................................................................39
4.5. REPLACEMENT OF RESIDUAL OXYGEN SENSOR........................................40
5. INSTALLATION DRAWING................................................ 41
6. ORDERING OF SPARE PARTS............................................ 42

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1. INTRODUCTION
1.1. INTRODUCTION
1.1.1. Purpose of the analyzer
The continuous COSA 9610™ analyzer determines online the Wobbe-index of a gas. The
COSA 9610™ can be used both, as feed forward and feedback analyzer for gases mixing
or as a feed forward analyzer for burning control. In order to achieve an optimal
performance of the analyzer system it is necessary to read this manual thoroughly before
installation and start-up.
For the combustion of gas, air is required. When supplying the right quantity of air, the
gas will completely burn. This is the so-called stoichiometric air requirement of the gas.
Because of this, the Wobbe-index can also be seen as a value for the need of air in gas.
By burning the gas with a small excess of air, the flue gas will contain the remaining
oxygen from the air, which has not taken part in the combustion. When the Wobbe-
index of a gas changes, the stoichiometric air requirement and the percentage of the
remaining oxygen in the flue gas will change simultaneously. By measuring the
concentration of oxygen in the flue gas, after calibrating the instrument with two gasses
with known Wobbe-index, the Wobbe index can be calculated.
1.2. THE COSA 9610™ ANALYZER
The COSA 9610™ features fast response time and high accuracy. These features make it
unique over conventional Wobbe index analyzers. The oxygen concentration in the air is
considered as constant, namely 20.95%. Functionally we can divide the analyzer-unit in 3
major parts:
•Sample System
•Electronics compartment
•Oven compartment
Optionally the COSA 9610™ can be built in an explosion proof execution. In explosion
proof execution, the analyzer is extended with a purge system.

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1.2.1. Oven with oxygen sensor
The gas/air mixture is burnt catalytically in an oven, which is kept at 812ºC with a burning
spiral. The temperature is maintained with a temperature controller using a K-type
thermocouple. The oxygen sensor in the oven is a zirconium oxide cell. This is mounted
such, that one side is in contact with the outside air and the other side with the flue
gasses. At high temperatures, (600ºC) O2-ions in the ZrO2grating become mobile through
vacancies herein. By fixing porous Pt-electrodes at both sides of the ZrO2, O2, gas
molecules can through diffusion by an uptake of two electrons from the Pt electrode enter
the ZrO2as O2-ion, move to the other electrodes and be converted in gaseous O2again by
release of the two electrons.
Inlet
Air/Gas
Mixture
Oven
Heating Spiral Oxygen Sensor
Drain
Vent

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1.2.2. The sample system (SCS)
In the sample conditioning system (SCS), gas and air are mixed in a constant proportion,
such that a small excess of air is present (± 2.5% oxygen) in the flue gas. The gas and air
pressure, are equalized by a dome-loaded pressure reducer (or booster relay), where the
gas pressure governs the air pressure.
The booster relay has a temperature reducing effect; the gas/air mixing proportion can
therefore vary as consequence of variations in viscosity. Therefore, the temperature of the
gas and the air are equalized in a heat exchanger. The gas and air temperature are still at
surrounding temperatures, however, as long as gas and air fluctuate to the same extent
this hardly influences the mixing proportion. In case of large surrounding temperature
fluctuations, the calibration sequence has to be performed more often. Hereafter gas and
air are mixed in the mixing chamber. The mixing chamber is equipped with orifices in the
inlet nozzles. The gas and airflow are determined by a critical expansion over the orifices.
The turbulence created provides a homogeneous mixture.
The diameter ratio of the orifices, together with the ratio between gas and air pressure,
determine the mixing proportion.
After the mixing chamber, the mixture flow is divided into an excess flow to vent and a
flow to oven. The flow to the burning oven will be approximately 30-50 Nl/hr. The vented
stream is approximately 500 Nl/hr with a maximum 1000 Nl/hr.

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1.3. CALIBRATION PROCEDURE
The analyzer can be calibrated in three different ways:
•Single point calibration
Only one calibration gas is used. The value of the gas is chosen middle of the
measuring range. This is only used to correct any offset error to the measurements.
•Two point calibration
Two calibration gases are used. The low calibration gas is set at ± 20% of the
measuring range. The high calibration gas is set at ± 80% of the measuring range.
The advantage over a single point calibration is the increased accuracy over the entire
span.
•Three point calibration
This method uses three calibration gases and is mandatory for a dual range analyzer.
The medium range calibration gas must be in the middle of the measuring range.
All three calibration methods can be performed both manually and automatically:
•Manually
The operator navigates the procedure via on-screen menu to open the correct gas
valves to the analyzer. The operator controls the timing.
•Automatically
The analyzer itself controls the timing of the valves switching. When the measured
values stay within the specified tolerances, the newly calculated calibration
parameters will be accepted. Otherwise, the analyzer will keep the old value and
generates a CAL ERROR on the display and switch the system fault contact and
calibration fault contact.
The automatic calibration can be started as followed:
•Programmable time schedule (Timed calibration)
•Initiated manually via on-screen menu (Semi-automatic calibration)
•External host activates the calibration request contact (Remote calibration)
The one-point calibration/validation procedure will be executed as followed:
1. Analyzer activates calibration/validation contact.
2. The procedure pauses for the specified “Calibration Start Delay” time for the
external host to prepare for calibration/validation.
3. Process gas is switched off and the calibration gas is switch on.
4. The analyzer waits for the readings to stabilize up to the “Switch Time”.
5. Calibration gas is switched off and the process gas is switched on.
6. Analyzer deactivates calibration/validation contact.

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The two-point calibration/validation procedure will be executed as followed:
1. Analyzer activates calibration/validation contact.
2. The procedure pauses for the specified “Calibration Start Delay” time for the
external host to prepare for calibration/validation.
3. Process gas is switched off and the low calibration gas is switch on.
4. The analyzer waits for the readings to stabilize up to the “Switch Time”.
5. Low calibration gas is switched off and the high calibration gas is switched on.
6. The analyzer waits for the readings to stabilize up to the “Switch Time”.
7. High calibration gas is switched off and the process gas is switched on.
8. Analyzer deactivates calibration/validation contact.
The three-point calibration/validation procedure will be executed as followed:
1. Analyzer activates calibration/validation contact.
2. The procedure pauses for the specified “Calibration Start Delay” time for the
external host to prepare for calibration/validation.
3. Process gas is switched off and the low calibration gas is switch on.
4. The analyzer waits for the readings to stabilize up to the “Switch Time”.
5. Low calibration gas is switched off and the medium calibration gas is switched on.
6. The analyzer waits for the readings to stabilize up to the “Switch Time”.
7. The analyzer switched the gas stream to the high range mixing chamber.
8. The analyzer waits for the readings to stabilize up to the “Switch Time”.
9. Medium calibration gas is switched off and the high calibration gas is switched on.
10.The analyzer waits for the readings to stabilize up to the “Switch Time”.
11.High calibration gas is switched off and the process gas is switched on.
12.Analyzer deactivates calibration/validation contact.
Between each step of the calibration process a switch time is programmed enabling the
analyzer to stabilize. After the switch time the new value is used in the calibration
algorithm. The calibration gas switch time is user programmable. By default, it is set at
120 seconds. Depending on the distance to the calibration gases it may be necessary to
change to a longer or shorter delay.

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1.4. EXTENDED (DUAL)RANGE OPTION
1.4.1. Operation
When the measuring range of the analyzer is larger than 40 MJ/Nm3, an extended range
option is available which covers a Wobbe index of 0-95 MJ/Nm3. This is accomplished by
adding a second gas orifice tube and selection valve to make changeover possible. The
dilution ratios of each orifice tube are chosen such that the measuring ranges overlap. Via
the software it is possible to create a 4/20mA current loop signal that covers the whole
range. It is necessary to establish a switch over point that must be calibrated. For this
reason the calibration system is expanded with an extra solenoid valve.

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1.5. SPECIFICATIONS COSA 9610™ WOBBE INDEX ANALYZER
1.5.1. Analyzer performance
Make Cosa Instrument Corporation
Service Natural gas, fuel-gas, biogas, etc.
Ranges Wobbe index 0-3000 BTU/scf (0-95 MJ/Nm3), span
0-1100 BTU/scf (40 MJ/Nm3) (selectable
CARI 0-20, span 0-10)
Accuracy ± 0.4% of measuring value natural gas
Repeatability ±0.7 BTU/scf (±0.03 MJ/Nm3)
Drift ±0.4 BTU/scf (±0.01 MJ/Nm3), 24 hours
Response time, base unit. T90<5 seconds†
2 isolated 4-20 mA outputs, 4 outputs total optional
Span and service selectable
Display & Optional Digital Output
Output
8 User-programmable contact relays
Safety General area or Explosion proof
† Wobbe w/o density cell or with streaming S.G. option
1.5.2. Utilities
Power supply 110 VAC, 50/60 Hz or 230 VAC/50 Hz
Power consumption 430 VA maximum
Instrument air 10 Nl/min (analyzer) at 3 barG (43psig)
20 Nl/min (Ex purge system) at 5.5 barG (80psig)
Sample 1 Nl/min at 2 barG (29psig)
1.5.3. Installation
Mounting Wall mounting
Dimensions 39 x 39 x 16 inches (1000 x 1000 x 400 mm)
Weight ± 330 lbs (150 kg)
Ambient temperature 50-104º F (10-40 °C)
Allow ambient temperature variation: ±45ºF (7 °C)
per 24 hours
Humidity 0-90%

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2. INSTALLATION
2.1. GENERAL
Upon receipt and unpacking of the COSA 9610™ a visual inspection must be carried out
to check for any visual damage, caused by transport. Any damage must be reported
immediately to:
COSA INSTRUMENT CORPORATION
New Jersey Office: Texas Office:
55 Oak Street 7125 North Loop East
Norwood, NJ 07648 Houston, TX 77028
Tel: [phone] Tel: [phone]
Fax: [phone] Fax: [phone]
New York Office: E-mail:
84G Horseblock Rd. [email protected]
Yaphank, NY 11980
Tel: [phone]
Fax: [phone]
We kindly ask you to submit photographs of the damage.
If the COSA 9610™ is supplied by the COSA INSTRUMENT CORPORATION, as part of a
complete package and built into a shelter or house, installation may differ from
hereunder described.
2.2. STORAGE
The COSA 9610™ must be stored frost-free and at a maximum temperature of 122ºF
(50°C), preferably in it’s original packing, and protected against direct sunlight and (rain)
water.
2.3. PLACEMENT
2.3.1. General
The COSA 9610™ can operate under ambient conditions between +41º F (5°C) and
+113ºF (45°C) and a maximum humidity of 90%.

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2.3.2. COSA 9610™ in general purpose execution (Type 01 & 02)
The COSA 9610™ is to be mounted against an even wall or structural steel construction.
Fixing lugs are located on each corner of the cabinet. Fixings used must be suitable for
the weight of the COSA 9610™ (±331 lbs/150kg).
The COSA 9610™ must be mounted on such a level above the floor or underneath
located obstacles that the oven drain can be connected to a drain header or a condense
bottle.
The COSA 9610™ can optionally be supplied on a 304L Stainless Steel freestanding
frame. This frame is to be placed on a flat surface (i.e. concrete slab). Two holes (∅12)
in the base of the frame enable the COSA 9610™ to be fixed to the floor
2.3.3. COSA 9610™ in explosion proof execution (Type 01-Ex & 02-Ex)
The COSA 9610™ is supplied on a 304L Stainless Steel freestanding frame. This frame is
to be placed on a flat surface (i.e. concrete slab). Two holes (∅12) in the base of the
frame enable the COSA 9610™ to be fixed to the floor.

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2.4. MECHANICAL CONNECTIONS
2.4.1. General
•Location and amount of connections may vary depending on type and execution of
the analyzer.
•Tubing connections on the COSA 9610™ are Swagelok double ferrule compression
type fittings for imperial sizes.
•Only seamless and annealed imperial size instrument tubing according ASTM A-249 at
a maximum permissible hardness of Rockwell B-90 may be used.
•Tubing must be cut off straight and de-burred thoroughly. (Inside and outside of
tubing cutting edge)
•The outside surface of the tube ends entering the fittings must be clean and free from
scratches.
•Nuts and ferrules do not have to and must not be removed to avoid mixing up of the
nuts and or ferrules
•Tubing must be pushed into the fitting onto the seat
•Hand-tighten the nut and mark the nut against the fitting
•Use a correct size wrench to lock the body of the fitting and tighten the nut with
another correct size wrench for 1- 1/4 turn for ¼” tube and 3/4 turn for 1/8” tube.
(Watch the marks)
•Before connecting the tubing to the analyzer they must be blown through with dry
nitrogen or instrument air to remove all particles.
•All connections must be checked against leakage prior to putting the analyzer in
operation or installing the tubing.
•Pressurise the lines with nitrogen or instrument air at 7bar maximum to perform leak
test. Check each connection with soap. (e.g. snoop)
•Make sure before pressurizing for leak-test that the power to the analyzer is off
(sample and calibration selection valves closed) and that the instrument air supply
isolation valve in the analyzer is closed.
•Vent connections must not be pressure tested while connected to the analyzer.
Disconnect and cap these tubes if leak test is required.
•Re-connection of the fittings is done by hand tightening the nut followed by wrench
tightening a maximum 1/4 turn.
•If a leak is detected, it might be fixed by tightening the fitting step by step a little
more (up to a 1/4 turn) until it is tight. Then the fitting has to be inspected if it has
not been over-tightened. This is done by disconnecting the fitting and to check if the
ferrules can still be rotated in relation to each other and the pipe. (If the ferrules can
also be moved in an axial direction the fitting is to loose) If the ferrules are stuck, the
pipe has to be cut just after the nut and newly installed according above instructions
using new ferrules. (The nut can be re-used)
•If this does not solve the problem, remove the fitting and inspect the fitting body for
damage. If it is damaged the complete fitting it must be replaced.

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•If the body is not damaged the pipe has to be cut just after the nut and newly
installed according above instructions using new ferrules. (The nut can be re-used)
•Disconnected fittings can be re-installed by hand tightening the nut followed by
wrench tightening for 1/4 turn. It is recommended to perform a leak test after re-
installation.
2.4.2. Sample supply
The sample supply line must be heat-traced and/or insulated to keep the gas above dew
point. Check your sample data for required temperature.
Sample inlet connection on the analyzer is identified with a tag-plate.
The sample connection on the analyzer is for 1/8”OD tubing. Tubing size to the process
may require a different tube size, this should be determined taking in account process
pressure, sample line length and acceptable lag time.
2.4.3. Calibration gasses
Calibration gas composition is depending on range and process gas. COSA INSTRUMENT
can advise suitable compositions.
For a single range analyzer, 2 calibration gasses (low and high value) are recommended.
For a dual range analyzer, 3 calibration gasses (low/medium and high value) are
mandatory.

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2.5. ELECTRICAL CONNECTIONS
2.5.1. COSA 9610™ in general purpose execution
Power supply cables
The COSA 9610™ requires one power supply.
•Analyzer electronics
The power has to be connected to the switch outside the electronics cabinet. The
cable has to lead into the switch through a NEC approved cable gland. The analyzer
is standard equipped with a suitable gland. After connecting the wires and performing
the required connection tests the unit is ready for operation. For termination details
see specific drawings.
•Sample system heating
The heater power is connected to the solid state relay, that is controlled by the
sample compartment heater controller. A cable gland is mounted between the
electronics cabinet and SCS. For termination details see specific drawings.
Signal cables
The COSA 9610™ has multiple input and output signals, which can be split in two groups,
analog and digital signals. For both groups, an NEC approved cable gland for use with
multi core cables are foreseen.
If more entries are required, only NEC approved type cable glands are allowed to be used
and it has to be made sure that they are in good electrical contact with the yellow
personated sink layer on the electronics enclosure surface (paint locally to be removed
with a detergent). For termination details see specific drawings.
2.5.2. COSA 9610™ in explosion proof execution
Power supply cable
The COSA 9610™ requires only one power supply. The power supply cable has to be
connected in the EExd switch.
Please note that it is not permitted to drill extra entries in this switch. For details see
specific drawings.

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Signal cables
The COSA 9610™ has multiple input and output signals, which can be split in two groups,
analog and digital signals. Please make sure that the cable glands used are EExd/NCE
certified. Please note that it is not permitted to drill extra holes in this box. For details
see specific drawings.
Analog signals
The COSA 9610™ has two 4-20mA analog outputs (4 optional). The signals can be user-
programmed to represent various measurement readings, such as Wobbe index and CARI
index. The analog output signals should be wired via isolating barriers, customer
supplied in safe area. Please note that these barriers are to be connected to an intrinsic
safe earth (I/S). When no intrinsic safe earth is available the barriers may be connected
to a potential free earth (PE) with a resistance of less than 1Ω.
Digital signals
The digital signals are divided in three, Digital outputs (alarm/status), digital input, and
RS-485 serial signals. For details see specific drawings.

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3. IN OPERATION
3.1. START-UP SAMPLE CONDITIONING SYSTEM
The sample conditioning system is located in the left-hand compartment. This chapter
describes how the components of the sample conditioning system should be set up, in
correct order, so a perfect start-up of the total analyzer system can be achieved. The
instructions hereunder should be performed step by step.
3.1.1. Inspection, visual and external connections
Perform a visual inspection of the system and close all shut-off valves in the system.
Check the connecting fittings of the supply tubes to be correctly fitted and are not
leaking. This can be checked quite simple by unscrewing the bolt from the fitting and
then check if "Front and Back ferrule" of the fitting are able to rotate but cannot be
moved in an axial direction. If this is not the case, this tube must be renewed. Then turn
the bolt by hand and afterwards tighten it a maximum 1/4 turn with a suitable spanner.
The supply and drainage tube can now be connected.
Because the supply line is under pressure and has been closed off on the COSA 9610™
side, the connecting fittings can be squirted with soap in order to detect any possible leaks.
When bubbles appear this indicates a leak and the tube concerned must immediately be
closed off at the supply point. Inspect the fitting and tube, replace components when
necessary.
3.1.2. Air orifice selection
Before the COSA 9610™ is set into operation, the range of measurement must be
established. The air orifice is selected on the basis of the desired range of measurement.
The COSA 9610™ is standard equipped with one of each of the following orifices:
•Gas: .0079 in to .0118 in (0.2 mm and 0.3mm)
•Air: 0.55/0.60/0.65/0.70/0.75 for a dual range version extended with 0.80/0.85 and
0.90.

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Relationship of pressure differential (gas/air) versus Wobbe-Index with different air
orifices and a fixed residual oxygen concentration of 5% (theoretically determined).
It is therefore recommended that a residual oxygen concentration of 2.5% is chosen
corresponding to the reference point. Possible fine-tuning of the reference point, (for the
purpose of attaining the correct O2%); can be carried out by giving the booster relay a
positive or negative offset.
3.1.3. Opening of shut-off valves
Open the shut-off valve with identification plate "instrument air supply.
3.1.4. Setting of gas pressure reducer
Turning the adjusting cap clockwise can raise the pressure of the gas pressure reducer.
The set outlet pressure can be read immediately from the pressure indicator mounted on
the reducer.
Set the output gas pressure to 2 BARG (30 PSIG).
3.1.5. Adjusting flow with flow meters
Unscrew the needle valve of the by-pass flow regulator completely (turn counter
clockwise). Use the "By-pass flow meter" needle valve; throttle back the flow so that the
"Analyzer flow meter" shows a flow of 0.5-0.8Nl/hr.
3.1.6. Adjusting booster relays
Set the chosen residual O2 set point with help of the booster relay. With the booster
relay it is possible to give a small negative (i.e. the gas pressure is higher than the air
pressure) or positive offset of max 0.5 bar, as set point correction or as pressure drop
compensation over the air- and gas tubes in the heat exchanger.
In order to achieve the necessary offset pressure, the insert with internal hexagon at the
top of the booster relay must be removed. By doing this, the slotted adjusting screw is
accessible by means of a small rotation counter clockwise, a bigger negative offset is
reached. In other words, the air pressure is lowered in comparison with the gas
pressure. The correct choice of a negative rather than a positive offset needs to be used
for proper analyzer operation. The chosen residual oxygen concentration, combined with
the average of the chosen range of measurement, gives according to these curves the
selection of the air nozzle and an indication for the booster offset.

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*Caution
The adjusting screw is located in the gas compartment of the relay. When the insert is
released, gas will escape. Be prepared before the relay is going to be adjusted, e.g. have
the right equipment readily available, so the gas compartment has to be open for only a
minimum of time.
After this adjustment the insert must be fitted again and the offset can be checked. The
offset adjustment can be checked by reading the air and gas pressure indicators. This
operation must be repeated until the desired residual oxygen concentration is reached.
After this the insert is fitted with sealing tape, assembled and then checked for leakage by
means of either a gas leak detector or soap.
It is advisable; to carry out a check on the booster relay adjustment with high Wobbe-
Index calibration gas, directly after setting up the booster set point. Using the on-screen
menu, select 2 Points manual (Dual Range manual for dual range analyzer) validation.
Proceed to the “Wait for cal gas 2 to stable” step (“Wait for cal gas 3 to stable” for dual
range analyzer). When the signals become stable, the display will show the Residual O2
mV-value suitable to this calibration gas. The setting of the booster relay is right when the
mV-value stays below 67 mV. If not, a positive offset should be set with help of the
booster relay, so that relative more air will be added and the mV value will fall.
The required Residual O2 mV-signal should be around 65mV for the highest expected
Wobbe value.