Analytical Industries Inc (AII) GPR-2900 Operating Manual

Technical Specifications *

Accuracy: < 2% of FS range under constant conditions
Analysis:

Application:

Approvals: CE
Area Classifica-

Alarms:

Calibration:

Compensation: Barometric pressure and temperature
Connections: 1/8" compression tube fittings
Controls:

Display:

Enclosure: Painted aluminum 6” x 4” x 4” panel mount
Flow: Not flow sensitive, 1-2 SCFH recommended
Linearity: > .995 over all ranges
Pressure:

Power: Universal; specify 100/120/220/240 VAC or 12-28 VDC
Range ID:

Response Time: 90% of final FS reading < 10 seconds
Sample System: None
Sensitivity: < 0.5% of FS range
Sensor Model:

Sensor Life:

Signal Output: 4-20mA non-isolated or 1-5V
Temp. Range: 5ºC to 45ºC (GPR sensor); -10ºC to 45ºC (XLT sensor)

0-1%, 0-5%, 0-10%, 0-25% FS ranges;
optional 0-1%, 0-5%, 0-10%, 0-100% FS ranges:
auto-ranging or fixed single range

Oxygen analysis in inert, helium, hydrogen, mixed and
acid (CO2) gas streams

General purpose
2 adjustable form C relay contacts non-latching; “weak

sensor” indicator; power failure; system failure
Max interval—3 months. Air calibrate with clean source

of certified span gas, compressed, or ambient (20.9%
O2) air on 0-25% range.

Water resistant keypad; menu driven range selection,
calibration, alarm and system functions

Graphical LCD 5” x 2.75”; resolution .001%; displays

real time ambient temperature and pressure

Inlet - regulate to 5-30 psig to deliver 1-2 SCFH flow;
vent - atmospheric

4-20 mA non-isolated or 1-5V; option: relay contacts
(eliminates alarms)

GPR-11-60-4 for non-acid (CO2) gas streams
XLT-11-24-4 for gases containing > 0.5% CO2

GPR-11-60-4 60 months in air at 25ºC and 1 atm
XLT-11-24-4 24 months in air at 25ºC and 1 atm

GPR-2900

Oxygen Analyzer

Panel Mount Configuration for OEM Applications

Advanced Sensor Technology

 Unmatched 60 Month Life
 Extended Operating Range –10⁰C
 Excellent Compatibility with 0-100% CO
 Sensitivity < 0.5% FS Range
 Fast Response
 No Maintenance

100-240 VAC or 12-28 VDC Power
2 Field Selectable Alarm Setpoints

Power and System Failure Alarms

Sensitivity 0.5% Full Scale
4 Ranges Standard
Auto Ranging or Single Fixed
4-20 mA or 1-5V Signal Output
Range ID 4-20 mA, 1-5V, or Relay Contacts

2

Warranty: 12 months analyzer; 12 months sensor
Wetted Parts: Corrosion resistant material; stainless steel optional

Optional Equipment

ISO 9001:2008 Certified

Sample conditioning accessories - contact factory

* Specification subject to change without notice.

2855 Metropolitan Place, Pomona, CA 91767 USA ♦ Tel: [phone], Fax: [phone], www.aii1.com, e-mail: [e-mail] Rev 10/15

INTERTEK Certificate No. 485

Advanced Instruments Inc.

GPR-2900

Oxygen Analyzer

Owner’s Manual

2855 Metropolitan Place, Pomona, California 91767 USA ♦ Tel: [phone], Fax: [phone], e-mail: [e-mail]

Table of Contents

Introduction 1
Quality Control Certification 2
Safety 3
Features & Specifications 4
Operation 5
Maintenance 6
Spare Parts 7
Troubleshooting 8
Warranty 9
Material Safety Data Sheets 10
Correlating readings - LCD display to 4-20mA output Appendix B

Advanced Instruments Inc.

Drawings A/R

1 Introduction

Your new oxygen analyzer is a precision piece of equipment designed to give you years of use in variety of industrial oxygen
applications.

This analyzer is designed to measure the oxygen concentration in inert gases, gaseous hydrocarbons, hydrogen, a variety of gas
mixtures and acid gases containing from 0-100% CO

In order to derive maximum performance from your new oxygen analyzer, please read and follow the guidelines provided in this
Owner’s Manual.

The serial number of this analyzer may be found on the inside the analyzer. You should note the serial number in the space
provided and retains this Owner’s Manual as a permanent record of your purchase, for future reference and for warranty
considerations.

Serial Number: _______________________
Every effort has been made to select the most reliable state of the art materials and components designed for superior

performance and minimal cost of ownership. This analyzer was tested thoroughly by the manufacturer for best performance.
However, modern electronic devices do require service from time to time. The warranty included herein plus a staff of trained
professional technicians to quickly service your analyzer is your assurance that we stand behind every analyzer sold.

Advanced Instruments Inc. appreciates your business and pledge to make effort to maintain the highest possible quality
standards with respect to product design, manufacturing and service.

(for CO

2

background, the XLT series sensor must be used) present.

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2 Quality Control Certification

Date: Customer: Order No.: Pass

Model: GPR-2900 Oxygen Analyzer S/N __________________
Sensor:

Accessories:

Configuration:

Test

Final

Options:
Notes

( ) GPR-11-60-4 Oxygen Sensor
( ) XLT-11-24-4 Oxygen Sensor S/N __________________
Owner’s Manual
CABL-1008 Power Cord
CABL-1014 Connector Cable (GPR-2900W)
Ranges: 0-1%, 0-5%, 0-10%, 0-25%
A-1161-2 PCB Assembly Main / Display
A-1162-2 PCB Assembly Power Supply / Interconnection

Software version:
Power: ( ) 100/120/220/240 VAC
( ) 9-28 VDC non-loop
Enclosure: Panel mount 7W x 4”H x 4”D (panel cutout 6”W x 3”H)
System start-up diagnostics satisfactory
Alarm relays activate/deactivate with changes in O
Analog signal output 4-20mA
Alarm relays activate/deactivate with changes in O
Alarm bypass
Range ID 4-20mA reflects range changes
Baseline drift on zero gas < ± 2% FS over 24 hour period
Noise level < ± 1.0% FS
Span adjustment within 10-50% FS
Overall inspection for physical defects

1 of 1 due ASAP

concentration

2

concentration

2

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3 Safety Guidelines

General

This section summarizes the essential precautions applicable to the GPR-2900 Oxygen Analyzer. Additional precautions specific
to individual analyzer are contained in the following sections of this manual. To operate the analyzer safely and obtain
maximum performance follow the basic guidelines outlined in this Owner’s Manual.

Caution: This symbol is used throughout the Owner’s Manual to Caution and alert the user to recommended safety and/or
operating guidelines.

Danger: This symbol is used throughout the Owner’s Manual to identify sources of immediate Danger such as the presence of
hazardous voltages.

Read Instructions: Before operating the analyzer read the instructions.
Retain Instructions: The safety precautions and operating instructions found in the Owner’s Manual should be retained for

future reference.

Heed Warnings: Follow all warnings on the analyzer, accessories (if any) and in this Owner’s Manual.
Follow Instructions: Observe all precautions and operating instructions. Failure to do so may result in personal injury or

damage to the analyzer.

Pressure and Flow

Inlet Pressure: GPR-2900 Oxygen Analyzers is designed for flowing samples, equipped with 1/8” bulkhead tube fitting
connections on the side of the sensor flow housing (unless otherwise indicated, either fitting can serve as inlet or vent) and are
intended to operate at positive pressure regulated to between 5-30 psig.

Outlet Pressure: The sample gas vent pressure should be atmospheric.

Installation

Oxygen Sensor: DO NOT open the sensor. The sensor contains a corrosive liquid electrolyte that could be harmful if touched
or ingested, refer to the Material Safety Data Sheet contained in the Owner’s Manual appendix. Avoid contact with any liquid or
crystal type powder in or around the sensor or sensor housing, as either could be a form of electrolyte. Leaking sensors should
be disposed of in accordance with local regulations.

Mounting: The analyzer is approved for indoor use, outdoor use requires mounting in a secondary enclosure with the
appropriate NEMA rating. Mount as recommended by the manufacturer.

Power: Supply power to the analyzer only as rated by the specification or markings on the analyzer enclosure. The wiring that
connects the analyzer to the power source should be installed in accordance with recognized electrical standards and so they
are not pinched particularly near the power source and the point where they attach to the analyzer. Never yank wiring to
remove it from an outlet or from the analyzer.

Operating Temperature: The maximum operating temperature is 45º C.
Heat: Situate and store the analyzer away from sources of heat.
Liquid and Object Entry: The analyzer should not be immersed in any liquid. Care should be taken so that liquids are not

spilled into and objects do not fall into the inside of the analyzer.
Handling: Do not use force when using the switches and knobs. Before moving your analyzer be sure to disconnect the

wiring/power cord and any cables connected to the output terminals located on the analyzer.

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Maintenance

Serviceability: Except for replacing the oxygen sensor, there are no parts inside the analyzer for the operator to service.
Only trained personnel with the authorization of their supervisor should conduct maintenance.

Oxygen Sensor: DO NOT open the sensor. The sensor contains a corrosive liquid electrolyte that could be harmful if touched
or ingested, refer to the Material Safety Data Sheet contained in the Owner’s Manual appendix. Avoid contact with any liquid or
crystal type powder in or around the sensor or sensor housing, as either could be a form of electrolyte. Leaking sensors should
be disposed of in accordance with local regulations.

Troubleshooting: Consult the guidelines in Section 8 for advice on the common operating errors before concluding that your
analyzer is faulty.
Do not attempt to service the analyzer beyond those means described in this Owner’s Manual. Do not attempt to make repairs
by yourself as this will void the warranty as per Section 10 and may result in electrical shock, injury or damage. All other
servicing should be referred to qualified service personnel.

Cleaning: The analyzer should be cleaned only as recommended by the manufacturer. Wipe off dust and dirt from the outside
of the unit with a soft damp cloth then dry immediately. Do not use solvents or chemicals.

Nonuse Periods: If the analyzer is equipped with a range switch advance the switch to the OFF position and disconnect the
power when the analyzer is left unused for a long period of time.

4 Features & Specifications

Specifications are subject to change without notice. See last page for current specifications, this section left blank intentionally.

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Advanced Instruments Inc.

5 Operations

Principle of Operation

The GPR-2900 Oxygen Analyzer incorporates a variety of percentage range advanced galvanic fuel cell type sensors. This model
is configured for panel mounting and requires a 6”W x 3”H cutout with 4 holes for the studs located on the back side of the
analyzer’s front panel.

Optional mounting configurations include a 19” rack or wall mount enclosure with or without a sample system. Contact the
factory for additional information on options.

Advanced Galvanic Sensor Technology:

The sensors function on the same principle and are specific for oxygen. They measure the partial pressure of oxygen from low
ppm to 100% levels in inert gases, gaseous hydrocarbons, helium, hydrogen, mixed gases, acid gas streams and ambient air.
Gas streams with acid gases like CO2 in the background in concentrations greater than 0.5% require the use of an XLT Series
oxygen sensor to maintain accuracy and reasonable sensor life.

Oxygen, the fuel for this electrochemical transducer, diffusing into the sensor reacts chemically at the sensing electrode to
produce an electrical current output proportional to the oxygen concentration in the gas phase. The sensor’s signal output is
linear over all ranges and remains virtually constant over its useful life. The sensor requires no maintenance and is easily and
safely replaced at the end of its useful life.

Proprietary advancements in design and chemistry add significant advantages to an extremely versatile oxygen sensing
technology. The expected life of our new generation of percentage range sensors now range to five and ten years with faster
response times and greater stability. Another significant development involves expanding the operating temperature range for
percentage range sensors from -30°C to 50°C.

Electronics:

The signal generated by the sensor is processed by state of the art low power micro-processor based digital circuitry. The first
stage amplifies the signal. The second stage eliminates the low frequency noise. The third stage employs a high frequency filter
and compensates for signal output variations caused by ambient temperature changes. The result is a very stable signal.

Sample oxygen is analyzed very accurately. Response time of 90% of full scale is less than 10 seconds (actual experience may
vary due to the integrity of sample line connections, dead volume and flow rate selected) on all ranges under ambient
monitoring conditions. Sensitivity is typically 0.5% of full scale low range.

Additional features of the micro-processor based electronics include manual or auto ranging, isolated 4-20mA signal for signal
output and range ID. Whenever the analyzer is calibrated, a unique algorithm predicts and displays a message indicating a
‘weak sensor’ suggesting the sensor be replaced in the near future.

Users interested in adding their own sample handling or conditioning system are encouraged to consult the factory to ensure all
applicable conditions are addressed to ensure proper operation of the analyzer. Advanced Instruments Inc. offers a full line of
sample handling, conditioning and expertise to meet your application requirements. Contact us at 909-392-6900 or e-mail us at

[e-mail]

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Advanced Instruments Inc.

Calibration & Accuracy Overview

Single Point Calibration: As previously described
the galvanic oxygen sensor generates an electrical
current proportional to the oxygen concentration in
the sample gas. In the absence of oxygen the sensor
exhibits an absolute zero, e.g. the sensor does not
generate a current output in the absence of oxygen.
Given these linearity and absolute zero properties,
single point calibration is possible.

Pressure: Because sensors are sensitive to the
partial pressure of oxygen in the sample gas their
output is a function of the number of molecules of
oxygen 'per unit volume'. Readouts in percent are
permissible only when the total pressure of the
sample gas being analyzed remains constant. The
pressure of the sample gas and that of the calibration
gas(es) must be the same (reality < 1-2 psi).

Temperature: The rate oxygen molecules diffuse into the sensor is controlled by a Teflon membrane otherwise known as an
'oxygen diffusion limiting barrier' and all diffusion processes are temperature sensitive, the fact the sensor's electrical output
will vary with temperature is normal. This variation is relatively constant 2.5% per ºC. A temperature compensation circuit
employing a thermistor offsets this effect with an accuracy of +
independent of temperature. There is no error if the calibration and sampling are performed at the same temperature or if the
measurement is made immediately after calibration. Lastly, small temperature variations of 10-15º produce < 1% error.

Accuracy:

producing 'percent of reading errors', illustrated by Graph A below, such as +
of range resistors and the 'play' in the potentiometer used to make span adjustments and 2) those producing 'percent of full
scale errors', illustrated by Graph B, such as +
technology and the fact that other errors are 'spanned out' during calibration.
Graph C illustrates these 'worse case' specifications that are typically used to develop an analyzer's overall accuracy statement
of < 1% of full scale at constant temperature or < 5% over the operating temperature range. QC testing is typically < 0.5%
prior to shipment.

Example 1: As illustrated by Graph A any error, play in the multi-turn span pot or the temperature compensation circuit,
during a span adjustment at 20.9% (air) of full scale range would be multiplied by a factor of 4.78 (100/20.9) if used for
measurements of 95-100% oxygen concentrations. Conversely, an error during a span adjustment at 100% of full scale range is
reduced proportionately for measurements of lower oxygen concentrations.

Zero Calibration: In theory
signal output when exposed to an oxygen free sample gas. In reality
sampling oxygen free sample gas due to contamination or quality of the zero gas; minor leakage in the sample line connections;
residual oxygen dissolved in the sensor’s electrolyte; and, tolerances of the electronic components. The Zero Offset capability of
the analyzer is limited to 50% of lowest most sensitive range available with the analyzer.

In light of the above parameters, the overall accuracy of an analyzer is affected by two types of errors: 1) those

1-2% linearity errors in readout devices, which are really minimal due to today's

, the electrochemical galvanic fuel cell type oxygen has an absolute zero meaning it produces no

5% or better and generates an output function that is

5% temperature compensation circuit, tolerances

, expect the analyzer to generate an oxygen reading when

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Recommendation 1: Zero calibration, see Determining True Zero Offset below, is recommended only for online analyzers
performing continuous analysis below 5% of the lowest most sensitive range available with a ppm analyzer, e.g. analysis below

0.5 ppm on the 10 ppm range, or below 0.1% (1000 ppm) with a percent analyzer. Note 1: Once the zero offset adjustment is
made, zero calibration is not required again until the sample system connections are modified, or, when installing a new oxygen
sensor. As a result, zero calibration is not practical and therefore not recommended for higher ranges or portable analyzers.

Determining True Zero Offset:
stable reading or horizontal trend on an external recording device. Note 2: 24 hours is required to assure the sensor has
consumed the oxygen that has dissolved into the electrolyte inside the sensor while exposed to air or percentage levels of
oxygen. For optimum accuracy, utilize as much of the actual sample system as possible.

Span Calibration: Involves adjusting the analyzer electronics to the sensor’s signal output at a given oxygen standard.
Regardless of the oxygen concentration of the oxygen standard used, a typical span calibration takes approximately 10 minutes.

Note 3: The amount time required to get the analyzer back on line for normal use is influenced by a.) the level of oxygen
analysis anticipated during normal operation (also determines the initial analyzer selection), and, b.) whether the sensor is new
or has been in service for at least two weeks.

General guidelines
oxygen content below the stated thresholds:

¾ measurements above 1000 ppm or 0.1% require less than 3 minutes
¾ measurements above 100 ppm (parts-per-million analyzer) require less than 10 minutes
¾ measurements below 10 ppm (part-per-million analyzer) require 20 minutes if the sensor has been in service at ppm

levels for at least two weeks, and, 60 minutes if the sensor is new assuming the zero/purge/sample gas has an oxygen
concentration below 1 ppm

for analyzers to come online following span calibration and exposure to a zero/purge/sample gas with an

Recommendation 2: For 'optimum calibration accuracy' calibrate with a span gas approximating 80% of the full scale range
one or two ranges higher than the full scale range of interest (normal use) to achieve the effect illustrated on Graph A and
Example 1. Always calibrate at the same temperature and pressure of the sample gas stream.

Note 4: Calibrating with a span gas approximating 10% of the full scale range near the expected oxygen concentration of the
sample gas is acceptable but less accurate than ‘optimum calibration accuracy’ method recommended – the method usually
depends on the gas available. Calibrating at the same 10% of the full scale range for measurements at the higher end of the
range results in magnification of errors as discussed in Graph A and Example 1 and is not recommended. Of course the user can
always elect at his discretion to accept an accuracy error of +

Air Calibration:
calibrate the analyzer with ambient air (20.9% oxygen) and operate the analyzer within the stated accuracy spec on the lowest
most sensitive range available with the analyzer – there is no need to recalibrate the analyzer with span gas containing a lower
oxygen concentration. Except for Oxygen Purity Analyzers intended to measure elevated oxygen levels ranging from 50-100%
oxygen, calibrating either a ppm or percent analyzer with ambient air on the CAL or 0-25% range meets the 80% criteria
discussed in Recommedation 2.

Recommendation 3: Air calibrate the analyzer (with the exception of Oxygen Purity Analyzers intended to measure elevated
oxygen levels ranging from 50-100% oxygen) when operating a percent analyzer, installing and replacing a ppm oxygen sensor,
to verify the oxygen content of a certified span gas or when a certified span gas is not available to calibrate a ppm analyzer
(immediately following air calibration reintroduce a gas with a low oxygen concentration to expedite the return to ppm level
measurements as per Note 3).

Based on the inherent linearity of the electrochemical galvanic fuel cell type oxygen sensor enables the user to

Allow the analyzer approximately 24 hours to stabilize with flowing zero gas as evidenced by a

2-3% of full scale range if no other span gas is available.

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Installation Considerations

Gas Sample Stream: Ensure the gas stream composition of the application is consistent with the specifications and review the
application conditions before initiating the installation. Consult the factory if necessary to ensure the sample is suitable for
analysis.

Note: In natural gas applications such as extraction and transmission, a low voltage current is applied to the pipeline itself to
inhibit corrosion. As a result, electronic devices can be affected unless adequately grounded.

Contaminant Gases: A gas scrubber and flow indicator with integral metering valve are required upstream of the analyzer to
remove interfering gases such as oxides of sulfur and nitrogen or hydrogen sulfide that can produce false readings, reduce the
expected life of the sensor and void the sensor’s warranty if not identified at time of order placement. Installation of a suitable
scrubber is required to remove the contaminant from the sample gas to prevent erroneous analysis readings and damage to the
sensor or optional components. Consult the factory for recommendations concerning the proper selection and installation of
components.

Expected Sensor Life: With reference to the publish specification located as the last page of this manual, the expected life of
all oxygen sensors is predicated on oxygen concentration (< 1000 ppm or air), temperature (77°F/25°C) and pressure (1
atmosphere) in “normal” applications. Deviations are outside the specifications and will affect the life of the sensor. As a rule of
thumb sensor life is inversely proportional to changes in the parameters.

Optimum Accuracy: Determine if Zero Calibration is recommended for your application. If it is Zero Calibration should
precede Span Calibration and both should be repeated after the analyzer has been allowed to stabilize, typically 24-36 hours
after installation. For Span Calibration use a certified span gas with an oxygen content (balance nitrogen) approximating 80% of
the next higher full scale range above the intended measuring range is recommended for optimum accuracy, see Calibration
and Accuracy.

Assuming the initial zero is performed according to the procedure described herein, the analyzer should not require Zero
Calibration again until the either the sensor is replaced or a change is made to the sample system or gas lines, and, it should
not require Span Calibration again for up to 3 months under “normal” application conditions as described in the published
specifications. One of the unique features of analyzers based on the electrochemical galvanic fuel cell type oxygen sensor is the
fact that it can be field calibrated at the user’s discretion to whatever standard of certified span gas the user elects to use.

Zero Calibration: In theory
reality, expect the analyzer to generate an oxygen reading when sampling oxygen free sample gas due to contamination or
quality of the zero gas; minor leakage in the sample line connections; residual oxygen dissolved in the sensor’s electrolyte; and,
tolerances of the electronic components.

Zero calibration, see Determining True Zero Offset below, is recommended only
analysis below 5% of the lowest most sensitive range available with a ppm analyzer, e.g. analysis below 0.5 ppm on the 10 ppm
range, or below 0.1% (1000 ppm) with a percent analyzer. Note : Once the zero offset adjustment is made, zero calibration is
not required again until the sample system connections are modified, or, when installing a new oxygen sensor. As a result, zero
calibration is not practical and therefore not recommended for higher ranges or portable analyzers.

Determining True Zero Offset:
stable reading or horizontal trend on an external recording device. Note: 24 hours is required to assure the sensor has
consumed the oxygen that has dissolved into the electrolyte inside the sensor while exposed to air or percentage levels of
oxygen. For optimum accuracy, utilize as much of the actual sample system as possible.

Span Calibration: Involves adjusting the analyzer electronics to the sensor’s signal output at a given oxygen standard, e.g. a
certified span gas with an oxygen content (balance nitrogen) approximating 80% of the next higher full scale range above the
intended measuring range is recommended for optimum accuracy, see Calibration and Accuracy.

Recommendation:
ambient air (20.9% oxygen) and operate the analyzer within the stated accuracy spec on the lowest most sensitive range
available with the analyzer – there is no need to recalibrate the analyzer with span gas containing a lower oxygen
concentration. Calibrating either a ppm or percent analyzer with ambient air (with the exception of Oxygen Purity Analyzers
intended to measure elevated oxygen levels ranging from 50-100% oxygen) on the CAL or 0-25% range meets the 80% criteria
discussed above.

Based on the inherent linearity of the galvanic oxygen sensor enables the user to calibrate the analyzer with

, the oxygen sensor produces no signal output when exposed to an oxygen free sample gas. In

for online analyzers performing continuous

Allow the analyzer approximately 24 hours to stabilize with flowing zero gas as evidenced by a

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Advanced Instruments Inc.

Air calibrate the analyzer (with the exception of Oxygen Purity Analyzers intended to measure elevated oxygen levels ranging
from 50-100% oxygen) when operating a percent analyzer, installing and replacing a ppm oxygen sensor, to verify the oxygen
content of a certified span gas or when a certified span gas is not available to calibrate a ppm analyzer (immediately following
air calibration reintroduce a gas with a low oxygen concentration to expedite the return to ppm level measurements).

Materials: Assemble the necessary zero, purge and span gases and optional components such as valves, coalescing or
particulate filters, and, pumps as dictated by the application; stainless steel tubing is essential for maintaining the integrity of
the gas stream for ppm and percentage range (above or below ambient air) analysis; hardware for mounting.

Temperature: The sample must be sufficiently cooled before it enters the analyzer and any optional components. A coiled 10
foot length of ¼” stainless steel tubing is sufficient for cooling sample gases as high as 1,800ºF to ambient.

Pressure & Flow: All electrochemical oxygen sensors respond to partial pressure changes in oxygen. The sensors are equally
capable of analyzing the oxygen content of a flowing sample gas stream or monitoring the oxygen concentration in ambient air
(such as a confined space such in a control room or an open area such as a landfill or bio-pond).

Sample systems and/or flowing gas samples are generally required for applications involving oxygen measurements at levels
other than ambient air and when the pressure exceeds ambient. In these situations, the use of stainless steel tubing and fittings
is critical to maintaining the integrity of the gas stream to be sampled and the inlet pressure must always be higher than the
pressure at the outlet vent which is normally at atmospheric pressure. The sensor is exposed to sample gas that must flow or
be drawn through metal tubing via 1/8” compression inlet and vent fittings, a stainless steel sensor housing with an o-ring seal
to prevent the leakage of air and stainless steel tubing.

Flow rates of 1-5 SCFH cause no appreciable change in the oxygen reading. However, flow rates above 5 SCFH generate
backpressure and erroneous oxygen readings because the diameter of the integral tubing cannot evacuate
the sample gas at the higher flow rate. The direction the sample gas flows is not important, thus either
tube fitting can serve as the inlet or vent – just not simultaneously.

A flow indicator with an integral metering valve upstream of the sensor is recommended as a means of
controlling the flow rate of the sample gas. A flow rate of 2 SCFH or 1 liter per minute is recommended for
optimum performance.

Caution: Do not place your finger over the vent (it pressurizes the sensor) to test the flow indicator when
gas is flowing to the sensor. Removing your finger (the restriction) generates a vacuum on the sensor and
may damage the sensor (voiding the sensor warranty). To avoid generating a vacuum on the sensor (as
described above) during operation, always select and install the vent fitting first and remove the vent
fitting last.

Application Pressure - Positive: A flow indicator with integral metering valve positioned upstream of
the sensor is recommended for controlling the sample flow rate between 1-5 SCFH. To reduce the possibility of leakage for low
ppm measurements, position a metering needle valve upstream of the sensor to control the flow rate and position a flow
indicator downstream of the sensor. If necessary, a pressure regulator (with a metallic diaphragm is recommended for optimum
accuracy, the use of diaphragms of more permeable materials may result in erroneous readings) upstream of the flow control
valve should be used to regulate the inlet pressure between 5-30 psig.

Application Pressure - Atmospheric or Slightly Negative: For accurate ppm range oxygen measurements, an optional
external sampling pump should be positioned downstream of the sensor to draw the sample from the process, by the sensor
and out to atmosphere. A flow meter is generally not necessary to obtain the recommended flow rate with most sampling
pumps.

Caution: If the analyzer is equipped with an optional flow indicator with integral metering valve or a metering flow control
valve upstream of the sensor - open the metering valve completely to avoid drawing a vacuum on the sensor and placing an
undue burden on the pump. If pump loading is a consideration, a se
necessary to provide a bypass path so the sample flow rate is within the above parameters.

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valve on the pump’s inlet side may be

Advanced Instruments Inc.

Recommendations to avoid erroneous oxygen readings and damaging the sensor:

¾ Do not place your finger over the vent (it pressurizes the sensor) to test the flow indicator when gas is flowing to the

sensor. Removing your finger (the restriction) generates a vacuum on the sensor and may damage the sensor (voiding the
sensor warranty).

¾ Assure there are no restrictions in the sample or vent lines
¾ Avoid drawing a vacuum that exceeds 14” of water column pressure – unless done gradually
¾ Avoid excessive flow rates above 5 SCFH which generate backpressure on the sensor.
¾ Avoid sudden releases of backpressure that can severely damage the sensor.
¾ Avoid the collection of liquids or particulates on the sensor, they block the diffusion of oxygen into the sensor
¾ If the analyzer is equipped with an optional integral sampling pump (positioned downstream of the sensor) and a flow

control metering valve (positioned upstream of the sensor), completely open the flow control metering valve to avoid
drawing a vacuum on the sensor and placing an undue burden on the pump.

Moisture & Particulates: Installation of a suitable coalescing or particulate filter is required to remove condensation, moisture
and/or particulates from the sample gas to prevent erroneous analysis readings and damage to the sensor or optional
components. Moisture and/or particulates do not necessarily damage the sensor, however, collection on the sensing surface can
block or inhibit the diffusion of sample gas into the sensor resulting in a reduction of sensor signal output – and the appearance
of a sensor failure when in fact the problem is easily remedied by blowing on the front of the sensor. Consult the factory for
recommendations concerning the proper selection and installation of components.

Gas Connections: Inlet and outlet vent gas lines for ppm analysis require 1/8” or ¼” stainless steel compression fittings; hard
plastic tubing with a low permeability factor can be used percentage range measurements.

Power Connection: Locate the appropriate source of to meet the analyzer or analyzer requirements, ensure that is properly
grounded and meets the area classification.

.

Mounting the Analyzer & Sensor:

The GPR-2900 consists of a six (6) foot insulated cable which
connects the sensor to the rear of the electronics module, a long
life maintenance free oxygen sensor and a sensor flow housing
equipped with 1/8” diameter stainless steel compression fittings.

The compact design also lends itself to optional mounting
configuration such as a standard 19” rack or wall mount
enclosures, both of which can be equipped with optional sample
system components. Contact the factory for additional information.

Procedure:

1. The GPR-2900 front panel measures 7”W x 4”H x 4.5”D. This
compact configuration is designed for panel mounting directly
to any flat vertical surface, wall or bulkhead plate with the
appropriate 6”W x 3”H cut out and four ¼” diameter holes for
insertion of the mounting studs located on the back side of
the front panel.

2. When mounting the analyzer position it approximately 5 feet
off the floor for viewing purposes and allow sufficient room
for access to the terminal connections at the rear of the
enclosure. Note: The proximity of the analyzer to the sample
point and use of optional sample conditioning components have an impact on sample lag time.

3. Position the sensor flow housing along any flat surface. The base of sensor flow housing is fabricated with two 6/32
mounting holes. The oxygen sensor is not position sensitive but it is recommended to orient the sensor flow housing with
the female threaded opening facing the ceiling.

4. Next screw the sensor into sensor flow housing, snug the sensor’s sealing o-ring but do not over tighten or crush it.

5. Register the female plug molded to the cable with the mating male connector attached to the rear of the sensor.

6. Remove the shorting device, normally a formed spring type wire, from the sensor, push the registered mating connectors
together and turn the knurled lock ring on the molded plug until finger tight on the sensor’s connector.

7. Connect the four wires of the cable, following the color coding above the terminal block, at the rear of the analyzer.

8. Attach the flow housing to the mounting position determine above.

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