Ametek WDG-V User manual

WDG-V, WDG-VC, WDG-VCM, WDG-VM
Combustion Analyzer
USER MANUAL
PN 9000-133-VE, Rev U
5000-017-PI rA

To obtain a PDF of this manual, visit our Products page at www.ametekpi.com.
Copyright Notice © 2021 AMETEK Process Instruments. All rights reserved.
The information and descriptions in this document are the sole property of AMETEK Process Instruments and may not be copied, reproduced, disseminated, or
distributed without explicit written permission from AMETEK Process Instruments.
The statements, congurations, technical data, and recommendations in this document are believed to be accurate and reliable at the time of this publication,
but AMETEK Process Instruments assumes no responsibility or liability for any errors or inaccuracies that may appear in this document.
AMETEK Process Instruments is not responsible for any infringement of patents or other rights of third parties that may result from the use of this document. The
content of this document is furnished for informational purposes only, is subject to change without notice, and does not represent a commitment or guaranty by
AMETEK Process Instruments.
AMETEK Process Instruments makes no warranty, express or implied, with respect to the content of this document. AMETEK Process Instruments shall not be
liable for any loss or damage, including consequential or special damages, resulting from any use of this information, even if loss or damage is caused by AMETEK
Process Instruments as a result of negligence or any other fault.

PN 9000-133-VE, Rev U
Contents
Safety Notes................................................................................................................................................vii
Electrical Safety .........................................................................................................................................vii
Grounding...................................................................................................................................................vii
Personnel and Equipment Safety Information............................................................................. viii
Important Notice to Users.......................................................................................................................x
Warning Labels...................................................................................................................................xi
Environmental Information – WEEE ............................................................................................xi
OVERVIEW .............................................................................................................................1-1
Analyzer Operations..............................................................................................................................1-1
Basic Elements of the Analyzer..................................................................................................1-2
Analyzer I/O.............................................................................................................................1-2
Analyzer Communications.................................................................................................. 1-2
How the Oxygen Measuring Cell Works.................................................................................1-3
Measuring Non-Combustible Gases .................................................................................1-4
Hydrocarbons in the Gas Sample.......................................................................................1-5
Analyzer Operations – WDG-VCM, Close-Coupled Extractive Flue Gas Analyzer............1-6
About the Analyzer Sample System.........................................................................................1-6
Detectors ...........................................................................................................................................1-7
Flow Sensor.......................................................................................................................................1-8
Temperature Sensors.....................................................................................................................1-9
Heaters................................................................................................................................................1-9
About the Analyzer Electronics .............................................................................................. 1-10
Alarm Contact Connections..................................................................................................... 1-11
Communicating With the Analyzer.......................................................................................1-12
Flame Arrestors............................................................................................................................. 1-13
Working in This Manual..................................................................................................................... 1-14
Supplemental Information – Where Can I Find It?................................................................... 1-14
INSTALLATION AND START-UP............................................................................................2-1
Safety Considerations ...........................................................................................................................2-1
Pre-Installation Requirements ...........................................................................................................2-2
Personnel Technical Level Required for Installation...........................................................2-2
Storage Prior to Installation ........................................................................................................2-2
Analyzer Site Preparation.............................................................................................................2-2
Unpacking and Inspecting the Equipment...........................................................................2-3
Tools, Equipment, and Supplies Required for Installation...............................................2-3
Common Operator Errors ....................................................................................................................2-4
Installing the Mechanical Components..........................................................................................2-5
Contents | iii

PN 9000-133-VE, Rev U
Installing the Sample Inlet Probe..............................................................................................2-5
Standard 1/8" NPT Probe Installation ...............................................................................2-6
Ceramic Probe or Long Probe Installation ....................................................................... 2-7
Probe Heater Installation (Optional)........................................................................................2-8
Installing the Exhaust Tube (Optional)................................................................................. 2-10
Installing the Analyzer ............................................................................................................... 2-11
Methods for Mounting the Analyzer ...............................................................................2-11
Analyzer Flush Mounting (Preferred Method).......................................................2-13
Customer-Supplied Pipe Nipple Analyzer Mounting...........................................2-14
Customer-Supplied Flange Analyzer Mounting ...................................................2-15
Installing the Remote Calibration Unit (Optional)...........................................................2-16
Standard RCU Installation.................................................................................................2-16
Combustibles RCU Installation.........................................................................................2-18
Calibration/Aspirator Air ...........................................................................................................2-20
Required Calibration Gases and Tubing.........................................................................2-20
Methane Span Gas.......................................................................................................2-20
Z-Purge Connections (Optional) ............................................................................................ 2-21
Z-Purge Shut-down Procedure .........................................................................................2-22
Aspirator and Manual Calibration Connections ............................................................... 2-23
Aspirator Air Connection....................................................................................................2-23
Aspirator N2Connections...................................................................................................2-23
Calibration Gas Connection..............................................................................................2-24
AC Power and Signal Connections................................................................................................ 2-25
General Wiring and Conduit Requirements....................................................................... 2-26
WDG-V Mains Supply Connections .................................................................................2-27
EMC Grounding, Shielding and Noise Protection............................................................ 2-28
EMC Grounding Method ....................................................................................................2-28
Transient and RFI Interference..........................................................................................2-29
Current Output Connections................................................................................................... 2-30
Standard Current Outputs.................................................................................................2-30
Alarm Contact Connections..................................................................................................... 2-32
Standard Alarm Connections ...........................................................................................2-32
Remote Calibration Unit Connections (Optional)............................................................ 2-33
Oxygen-Only Remote Calibration Unit Connections ..................................................2-33
Combustibles Remote Calibration Unit Connections .................................................2-33
Digital Input to Initiate Remote Calibration Unit.........................................................2-33
Digital Input to Initiate Remote Calibration Unit.........................................................2-35
Notes About Ducting .................................................................................................................2-35
Installing the User Interface/Communications Options........................................................ 2-36
Installing the PC Congurator Software (Typical Communication Option)...........2-36
Setting the Analyzer Address Using the Dip Switch (to Enable
Communications Between the Analyzer and the PC Congurator Software) ......2-36
Connecting the PC to the Analyzer..................................................................................2-37
Installing the AMEVision Display User Interface (Secondary Communication
Option).............................................................................................................................................2-38
iv | Thermox®WDG-V / VC / VCM / VM

PN 9000-133-VE, Rev U
Setting the Analyzer Address Using the Dip Switch (to Enable
Communications Between the Analyzer and the AMEVision Display User
Interface Unit).......................................................................................................................2-40
Connecting Analyzers to the AMEVision Display Unit ...................................................2-41
Connecting a Single Analyzer...........................................................................................2-41
Connecting Multiple Analyzers.........................................................................................2-41
Final Daisy Chain Connection Conguration Setting.................................................2-42
Customer I/O Connections...............................................................................................................2-43
Communication Troubleshooting Checks..........................................................................2-44
No Communications ...........................................................................................................2-44
Intermittent Communications..........................................................................................2-44
Setting the Flow...................................................................................................................................2-45
Setting the Flow Using the Display User Interface Flow Sensor Diagnostic .......... 2-45
LED Status Indicator............................................................................................................................2-46
Main Status LED (Light Pipe Visible From the Front).......................................................2-46
Printed Circuit Board (PCB) Status LEDs ..............................................................................2-48
MAINTENANCE AND TROUBLESHOOTING.........................................................................3-1
Aftermarket Excellence and Long-Term Commitment to Safety and Quality ..................3-2
Requesting Technical Support...................................................................................................3-3
Requesting Authorization to Return Equipment ................................................................3-3
Spare Parts List.........................................................................................................................................3-4
WDG-V Analyzer Spare Parts.......................................................................................................3-4
WDG-V Analyzer Spare Parts.......................................................................................................3-5
Diagnostics Flowcharts.........................................................................................................................3-6
Thermocouple Checks ..................................................................................................................3-6
Calibration/Aspirator Air Setup Checks..................................................................................3-7
AC Power Checks ............................................................................................................................3-8
Furnace Checks................................................................................................................................3-8
Process Pressure Checks (only if above 2 PSIG)....................................................................3-9
Cell Checks ........................................................................................................................................3-9
Flow Sensor Alarm Limits Checks .......................................................................................... 3-10
Maintenance.......................................................................................................................................... 3-11
Calibration...................................................................................................................................... 3-11
Safety Considerations ................................................................................................................3-11
General Troubleshooting.......................................................................................................... 3-12
Aspirator Air Not Pulling Sample From Process............................................................3-12
Leak Check.............................................................................................................................3-12
Sning for Leaks..................................................................................................................3-13
Pressurizing for Leaks..........................................................................................................3-13
Plugged Plumbing Check...................................................................................................3-13
Internal Wiring Diagram, Standard Analyzer .....................................................................3-14
Customer Connections Wiring Diagram, Standard Analyzer....................................... 3-15
Cleaning and Replacing Parts .................................................................................................3-16
Cleaning the Analyzer Enclosure......................................................................................3-16
Contents | v

PN 9000-133-VE, Rev U
Cleaning and Replacing Parts in the Measuring Cell ..................................................3-16
Replacing the Thermocouple............................................................................................3-18
Replacing the Combustibles / Methane Detectors ......................................................3-20
Combustibles Detector ...............................................................................................3-20
Methane Detector........................................................................................................3-20
Replacing the Flow Sensor.................................................................................................3-22
Replacing the Furnace ........................................................................................................3-24
Replacing the Box Heater...................................................................................................3-25
Replacing the Combustibles Block Heater (Only on Combustibles/Methane
Units).......................................................................................................................................3-26
Replacing the Sensor Board ..............................................................................................3-28
Alarm and Warning Messages......................................................................................................... 3-30
Alarms.............................................................................................................................................. 3-30
Warnings.........................................................................................................................................3-37
SPECIFICATIONS....................................................................................................................4-1
WDG-V Analyzer Specications .........................................................................................................4-2
WDG-VC Analyzer Specications ......................................................................................................4-4
WDG-VCM Analyzer Specications ..................................................................................................4-5
WDG-VM Analyzer Specications .....................................................................................................4-6
Remote Calibration Unit (RCU) Specications .............................................................................4-7
Approvals and Certications ..............................................................................................................4-7
WDG-V Analyzer Directives and Standards...........................................................................4-7
WDG-VC Analyzer Directives and Standards ........................................................................4-7
WDG-VCM Analyzer Directives and Standards ....................................................................4-7
WDG-VM Analyzer Directives and Standards .......................................................................4-8
Remote Calibration Unit (RCU) Directives and Standards ...............................................4-8
WDG-V Analyzer Marking ............................................................................................................4-9
FRENCH WARNINGS/FRANÇAIS ADVERSTISSEMENTS.......................................................5-1
NOTES SUR LA SECURITE..............................................................................................................5-1
Sécurité électrique .........................................................................................................................5-2
Mise à la terre ...................................................................................................................................5-3
Note importante aux utilisateurs..............................................................................................5-3
Sommaire de Sécurité Générale................................................................................................5-5
Utilisez un câblage adéquat................................................................................................ 5-5
Evitez les surcharges électriques ........................................................................................5-5
Mettez à la terre l’analyseur ................................................................................................ 5-5
Ne pas faire fonctionner sans capot..................................................................................5-5
Utilisez des fusibles adéquats ............................................................................................. 5-5
Ne faites pas fonctionner en atmosphère explosible .................................................... 5-5
PRECAUTIONS AUX DOMMAGES DE L’ANALYSEUR ............................................................5-6
Utilisez une alimentation électrique adéquate ..............................................................5-6
Ne faites pas fonctionner avec les défaillances suspectes ...........................................5-6
Mise à la terre CEM (EMC), blindage et protection contre le bruit..............................5-6
vi | Thermox®WDG-V / VC / VCM / VM

PN 9000-133-VE, Rev U
Safety Notes
WARNINGS, CAUTIONS, and NOTES contained in this manual emphasize critical
instructions as follows:
Important information that should not be overlooked.
An operating procedure which, if not strictly observed, may result in personal
injury or environmental contamination.
An operating procedure which, if not strictly observed, may result in damage
to the equipment.
Burn hazard. Hot surface. Do not touch, allow to cool before servicing.
Electrical Safety
Up to 5 kV may be present in the analyzer housings. Always shut down power
source(s) before performing maintenance or troubleshooting. Only a qualied
electrician should make electrical connections and ground checks.
Any use of the equipment in a manner not specied by the manufacturer may
impair the safety protection originally provided by the equipment.
Grounding
Instrument grounding is mandatory. Performance specications and safety protection
are void if instrument is operated from an improperly grounded power source.
Verify ground continuity of all equipment before applying power.
Contents | vii

PN 9000-133-VE, Rev U
Personnel and Equipment Safety Information
This section describes important safety information to avoid personal injury and dam-
age to the equipment while installing, operating, maintaining, or servicing the equip-
ment. All safety regulations, standards, and procedures at the analyzer location must
be followed.
All personnel involved with the installation, start-up, operation, maintenance, service, or
troubleshooting of the analyzer must review and follow these Warnings and Cautions.
Do Not Operate without Covers
To avoid electric shock or re hazard, do not operate this product with covers
or panels removed.
Use Caution When Lifting
Use caution when lifting the analyzer from its crate.
Use Proper Attire
Equipment is hot, user should wear protective groves while handling the
equipment.
Do Not Operate in Explosive Atmosphere
To avoid injury or re hazard, do not operate this product in an explosive
atmosphere unless you have purchased options that are specically designed
for these environments.
Use Proper Wiring
To avoid re hazards, use only the wiring specied in the “Installation and
Start-Up” chapter of this manual.
Avoid Electrical Overload
To avoid electrical shock or re hazard, do not apply a voltage to a terminal
that is outside the range specied for that terminal.
viii | Thermox®WDG-V / VC / VCM / VM

PN 9000-133-VE, Rev U
Ground the Product
Follow the grounding instructions provided in the “Installation and Start-Up”
chapter of this manual. Before making connections to the input or output
terminals of this product, ensure that the product is properly grounded.
Use Proper Fuse
To avoid re hazard, use only the fuse type and rating specied for this product.
Use Proper Power Source
Do not operate this product from a power source that applies more than the
voltage specied.
Do Not Operate with Suspected Failures
If you suspect there is damage to this product, have it inspected by qualied
service personnel.
Contents | ix

PN 9000-133-VE, Rev U
Important Notice to Users
The following applies to the WDG-V Division 2 Models:
Power, input, and output (I/O) wiring must be in accordance with Class I, Division 2
wiring methods [Article 501-4(b) of the National Electric Code, NFPA 70] and in accor-
dance with the authority having jurisdiction.
Explosion hazard – Substitution of components may impair suitability for
Class I, Class II, Division 2.
Explosion hazard – When in hazardous locations, turn o power before replac-
ing or wiring modules.
Explosion hazard – Do not disconnect equipment unless power has been
switched o or the area is known to be nonhazardous.
This equipment is suitable for use in Class I and Class II, Division 2, Groups A, B,
C, D and Groups E, F, G or Nonhazardous locations only.
The maximum ambient temperature for the analyzer is 60 °C (140 °F).
The WDG-V Analyzer and AMEVision Display User Interface is a complex piece of
equipment that should only be serviced by a qualied service technician with exper-
tise in instrument technology and electrical systems. AMETEK recommends that all
equipment requiring service be sent back to the factory. You should only attempt to
repair or service this equipment after receiving training from an AMETEK/P&AI Divi-
sion training representative. If you decide to service this equipment be aware that high
voltages, high temperatures, and other potentially hazardous conditions may arise.
For Class II, Division 2 Hazardous Locations:
1. Where combustible dust has accumulated within the protected enclosure, the
protected enclosure shall be opened and the dust removed before pressurizing.
2. Adjacent enclosures connected to the main enclosure shall be permitted to be col-
lectively pressurized to prevent the entrance of dust if there is communication to
maintain the specied pressure at all points.
x | Thermox®WDG-V / VC / VCM / VM

PN 9000-133-VE, Rev U
Warning Labels
These symbols may appear on the instrument in order to alert you of existing conditions.
Protective Conductor Terminal
(BORNIER DE L’ECRAN DE PROTECTION)
Schutzerde
Caution – Risk of electric shock
(ATTENTION – RISQUE DE DÉCHARGE ÉLECTRIQUE)
Achtung – Hochspannung Lebensgefahr
Caution – Refer to accompanying documents
(ATTENTION – SE RÉFERER AUX DOCUMENTS JOINTS)
Achtung – Beachten Sie beiliegende Dokumente
CAUTION – Hot Surface
(ATTENTION – SURFACE CHAUDE)
Achtung – Heiße Oberäche
Environmental Information – WEEE
This AMETEK product contains materials that can be reclaimed and recycled. In some
cases the product may contain materials known to be hazardous to the environ-
ment or human health. In order to prevent the release of harmful substances into the
environment and to conserve our natural resources, AMETEK recommends that you
arrange to recycle this product when it reaches its“end of life.”
Waste Electrical and Electronic Equipment (WEEE) should never be disposed of in a
municipal waste system (residential trash). The Wheelie Bin marking on this product is
a reminder to dispose of the product properly after it has completed its useful life and
been removed from service. Metals, plastics, and other components are recyclable and
you can do your part by doing one of the following steps:
• When the equipment is ready to be disposed of, take it to your
local or regional waste collection administration for recycling.
• In some cases, your“end of life” product may be traded in for
credit towards the purchase of new AMETEK instruments. Contact
your dealer to see if this program is avail-able in your area.
• If you need further assistance in recycling your AMETEK product,
contact us through our Customer Support page at https://www.
ametekpi.com/customersupport/requestsupport.
Contents | xi

PN 9000-133-VE, Rev U
This page intentionally left blank.
xii | Thermox®WDG-V / VC / VCM / VM

PN 9000-133-VE, Rev U
Overview
Analyzer Operations
Designed for fast response in a wide range of ue gas applications, the analyz-
er mounts directly on the combustion process to provide continuous measure-
ment of oxygen, or oxygen and combustibles, or oxygen, combustibles, and
methane.
A sample is drawn from the process stream by means of an air-operated aspira-
tor and is immediately returned to the process. A portion of this gas rises past
the oxygen measuring cell and combustibles detector and returns to the pri-
mary loop. All sample wetted parts are heated to 200 °C maintain the sample
above the dewpoint of the gas.
Follow these cautions when working on the analyzer:
Do not turn on the aspirator until the analyzer has been turned on
and is hot – preferably 24 hours. Also, if you turn o the analyzer or
the process is shut down, turn o the aspirator air to avoid plugging
problems.
Remove AC power from the analyzer and allow it to cool for at least
90 minutes before performing any maintenance or troubleshooting
activities.
The outside of the analyzer cover and all analyzer assembly com-
ponents are hot during normal operation (up to 260 °C/500 °F
inside the cover). Allow analyzer components to cool for at least 90
minutes before working inside the analyzer. Use caution and wear
appropriate gloves when handling components or when touching
the analyzer cover.
Overview |1-1

PN 9000-133-VE, Rev U
Basic Elements of the Analyzer
The WDG-V series analyzer consists of the following basic systems:
• Plumbing
All inlet and outlet tubing, O2cell housing, and the combustibles ow
block. Also includes the calibration gas inlet and aspirator assembly, ow
sensor, and the aspirator used to pull the sample into the analyzer.
• Measuring System
The oxygen cell, combustibles detector, methane detector, and ow sen-
sor.
• Temperature System
The electrical cell heater (furnace), sensor case heaters, the Type K
Thermocouple (maintains cell operating temperature). The sensing cell
operates at a constant temperature. The circuit board in the analyzer elec-
tronic box switches power to the furnace from the AC mains connected to
the analyzer. This board also provides cold junction compensation to the
thermocouple circuit.
Analyzer I/O
All required I/O comes with the analyzer. See “About the Analyzer Electronics”
for descriptions.
Analyzer Communications
The WDG-V is a complete standalone unit. No separate controller is required.
The analyzer is congured, calibrated and monitored using the MODBUS RTU
interface. Communication with the analyzer is provided via the Display User In-
terface, or the WDG-V Congurator Software via PC (standard with each unit).
1-2 | Thermox®WDG-V / VC / VCM / VM

PN 9000-133-VE, Rev U
How the Oxygen Measuring Cell Works
The sensing element is a closed-end tube made from ceramic zirconium oxide
stabilized with an oxide of yttrium or calcium. Porous platinum coatings on the
inside and outside serve as both a catalyst and as electrodes. At high tempera-
tures (generally above 650 °C/1200 °F), oxygen molecules coming in contact
with the platinum electrodes near the sensor become ionic.
• As long as the oxygen partial pressures on either side of the Cell are equal,
the movement is random and no net ow of ions occurs.
• If, however, gases having dierent oxygen partial pressures are on either
side of the Cell, a potentiometric voltage is produced. The magnitude of
this voltage is a function of the ratio of the two oxygen partial pressures.
• If the oxygen partial pressure of one gas is known, the voltage produced
by the Cell indicates the oxygen content of the other gas. A reference gas,
usually air (20.9 % O2), is used for one of the gases.
Figure 1-1.
Zirconium Oxide Cell principle
of operation.
Overview |1-3

PN 9000-133-VE, Rev U
The voltage of the Cell depends on temperature, and so the Cell is maintained
at a constant temperature. The oxygen content is then determined from the
Nernst equation:
E = In
RT
4F
O1
O2
where Rand Fare constants, Tis absolute temperature, and O1and O2are the
oxygen partial pressures on either side of the Cell.
Measuring Non-Combustible Gases
For measuring oxygen in non-combustibles gases, the calibration of an ana-
lyzer is obtained using the formula:
AT = 48.0 at 680°C
E = A*T*Log 20.9%
O2Unk%
Where Ais a constant, Tis the Cell temperature on an absolute scale (°C +273)
and O2Unk % is the unknown oxygen concentration of the gas to be ana-
lyzed, and which is calculated by the analyzer.
The Cell produces zero voltage when the same amount of oxygen is on both
sides. Voltage increases as the oxygen concentration of the sample decreas-
es. The voltage created by the dierence in the sample gas and the reference
air is transmitted to the microprocessor control unit and linearized to an
output signal.
Because of the high operating temperature of the cell, combustible
gases that are present may burn. When this occurs, the cell will gener-
ate high millivolts and cause the display to indicate less oxygen than is
actually in the gas (net oxygen content).
1-4 | Thermox®WDG-V / VC / VCM / VM

PN 9000-133-VE, Rev U
Hydrocarbons in the Gas Sample
When hydrocarbons are present in the gas sample, a combustion process oc-
curs when this gas sample is exposed to the high temperature of the zirconia
cell. An indication that hydrocarbons may be present in the gas sample is that
the oxygen reading will be lower than expected. For example, if a calibration
gas cylinder has an oxygen value of 20 PPM and 5 PPM of hydrogen (balance
nitrogen), the oxygen analyzer will read 17.5 PPM oxygen. The reduction of
oxygen is due to the combustion process where 5 PPM of hydrogen will com-
bine with 2.5 PPM of oxygen to form water. Thus, the oxygen analyzer will read
17.5 PPM rather than the actual 20 PPM oxygen.
The amount of oxygen reduction is dependent on the type of hydro-
carbons present in the sample gas.
Overview |1-5

PN 9000-133-VE, Rev U
Analyzer Operations – WDG-VCM, Close-Coupled Extractive
Flue Gas Analyzer
About the Analyzer Sample System
The WDG-VCM analyzer is ideal for natural gas-red power boilers or for those
using gas during start-up and shut-down. With this analyzer, you can monitor
oxygen and combustibles for maximum fuel eciency. In addition, the meth-
ane detector can be used for purge and light o cycles during start-up and
shut-down.
WDG-VCM analyzers with a combustibles detector are used for processes that
use natural gas for start-up and oil, fuel gas, or coal for primary fuel. Process
gas is drawn into the analyzer’s primary sample loop by an aspirator and
returns to process. Gas enters the split ow block that is separated by a bae
and contacts the hot-wire catalytic combustibles and methane detector. It
then passes the Zirconium Oxide cell, where the oxygen concentration is mea-
sured, before returning to the main sample loop and then back to the process.
Detectors are very delicate and should be handled with care.
Figure 1-2.
Typical WDG-V Analyzer
conguration.
1-6 | Thermox®WDG-V / VC / VCM / VM

PN 9000-133-VE, Rev U
Detectors
Component Function
Combustibles Detector The Combustibles Detector is a dual element device. The
elements dier only in that one is coated with a catalyst. The
catalyst causes oxidation to occur at a lower-than-normal tem-
perature. The temperature of the catalyzed element changes as
the combustible mixture burns. The temperature change causes
the resistance of the catalyzed element to change. The resistance
change is interpreted by the microprocessor and the corre-
sponding combustibles reading is displayed.
The catalytic combustibles detector will detect combustible gas
present in a sample. The sample must, however, contain enough
oxygen to fully burn the combustible present. The combus-
tibles detector responds to all unburned combustibles gases.
This includes gases such as CO and H2. You should attempt to
match your calibration gas with a mixture of CO and H2that
most closely matches the combustibles mix in your process. We
recommend using an even mixture of CO and H2as the combus-
tibles component within your span gas.
Examples:
• Flue gas containing 1000 PPM CO, 1000 PPM H2and 1 % O2
with an H2O, CO2, and N2balance will be sensed to contain
2000 PPM combustibles by the catalytic detector (provided
the combustibles calibration gas consists of equal parts CO
and H2.
• Flue gas containing 1000 PPM CO, 1000 PPM H2and 500 PPM
O2with a H2O, CO2, and N2balance will be sensed to contain
only 1000 PPM combustibles by the catalytic detector, since
there is less than stoichiometric oxygen present. In this case,
the combustibles detector output will be set to full scale.
• If there is little or no other combustible component in the ue
gas, the combustibles analyzer can be calibrated on a mixture
of CO and air to give a CO measurement.
Methane Detector The Methane Detector is a dual element device. The elements
dier only in that one is coated with a catalyst. The catalyst
causes oxidation to occur at a lower-than-normal temperature.
The temperature of the catalyzed element changes as the mix-
ture burns. The temperature change causes the resistance of the
catalyzed element to change. The resistance change is inter-
preted by the microprocessor and the corresponding reading is
displayed.
• The AMETEK catalytic methane detector will detect methane
gases present in a sample. The sample must, however, contain
enough oxygen to fully burn the methane present.
• The methane span gas should be 2 % CH4with 8–10 % oxygen
present in the mixture.
Overview |1-7

PN 9000-133-VE, Rev U
Flow Sensor
Component Function
Overview The aspirator creates a vacuum and pulls the process gas into the
analyzer. There are two paths for the gas to take.
• Immediately back to the process gas.
• Through the sample loop, past the cell and/or combustible
detector.
Calibrated at the factory, the ow sensor (see Figure 1-3 for
location) measures the sample ow through the sample loop.
The ow measurement is updated every 90 seconds. This delay
is used to allow the analyzer to eectively auto-zero to prevent
false alarms.
Figure 1-3.
RTD Flow Sensor.
1-8 | Thermox®WDG-V / VC / VCM / VM