Hoya Oxygen Equipment OM 25A User Manual

®
OXYGEN  
ANALYZER  
MODEL  
OM-25A  
USER’S GUIDE  
AND  
OPERATING  
INSTRUCTIONS  
R213M15 Rev. K  
manufactured by:  
 
PREFACE  
This manual describes the function, operation and maintenance of the  
Maxtec Model OM-25A hand-held oxygen analyzer. A member of  
Maxtec's MAXO2analyzer line of oxygen analyzers and monitors, the  
OM-25A utilizes the MAX-250 oxygen sensor and is engineered for fast  
response, maximum reliability and stable performance. The OM-25A is  
designed primarily for spot-checking oxygen concentration delivered by  
oxygen concentrator units, however, its internal sensor and adaptable  
sampling port make it suitable for a wide variety of oxygen analysis  
applications.  
THANK YOU  
Thank you for your purchase of a Maxtec MAXO2oxygen analyzer. We  
appreciate the time and energy you invest in selecting the equipment best  
suited to your needs. As repayment, we are supplying you with a reliable,  
high-quality instrument that, with proper care and operation, will provide  
you with years of exceptional service. We also encourage your  
comments or suggestions as to how our equipment, in any way, can  
better serve your needs. Please feel free to write, FAX or e-mail us at the  
address on the back of this manual c/o the Maxtec Marketing Department.  
NOTE: In order to obtain optimum performance from your MAXO2ꢀ  
analyzer, all operation and maintenance must be performed in  
accordance with this manual. Please read the manual thoroughly  
before using the analyzer and do not attempt any repair or  
procedure that is not described herein. Maxtec cannot warrant any  
damage resulting from misuse, unauthorized repair or improper  
maintenance of the instrument.  
WARNING  
The sensor of the MAXO2 Oxygen Analyzer (MAXO2) has been tested  
with various anesthesia gases including Nitrous oxide, Halothane,  
Isoflurane, Enflurane, Sevoflurane and Desflurane and found to have  
acceptable low interferance, the device in its entirety (including  
electronics) is not suitable for use in the presense of a flammable  
anesthetic mixture. Only the threaded sensor face and sample inlet  
connection may be allowed to contact such a gas mixture.  
i
 
To avoid explosion, do not operate the oxygen analyzer in the presence  
of flammable anesthetics or in an atmosphere of explosive gases.  
Operating the oxygen analyzer in flammable or explosive atmospheres  
may result in fire or explosion.  
Never allow an excess length tubing near the patient’s head or neck, as  
such could result in strangulation.  
Before use, all individuals who will be using the MAXO2 must become  
thoroughly familiar with the information contained in this Operation  
Manual. Strict adherance to the operating instructions is necessary for  
safe effective product performance. This product will perform only as  
designed if installed and operated in accordance with the manufacturer’s  
operating instructions.  
Use only genuine Maxtec accessories and replacement parts. Failure to  
do so may seriously impair the analyzer’s performance. Repair or  
alteration of the MAXO2 beyond the scope of the maintenance  
instructions or by anyone other than an authorized Maxtec service person  
could cause the product to fail to perform as designed.  
Calibrate the MAXO2 weekly when in operation and if enviromental  
conditions change significantly. (ie, Temperature, Humidity, Barometric  
Pressure. --- Refer to Calibration section of this manual).  
Use of the MAXO2 near devices that generate electrical fields may cause  
erratic readings.  
If the MAXO2 is ever exposed to liquids (from spills or immersion) or to  
any other physical abuse, turn the instrument OFF and then ON. This will  
allow the unit to go through its self test and make sure everything is  
operating correctly.  
Never autoclave, immerse or expose the MAXO2 (including sensor) to  
o
high temperatures (>70 C). Never expose the device to pressure,  
irradiation vacuum, steam, or chemicals.  
To protect the unit from potential leaky battery damage always remove  
batteries when the unit is going to be stored (not in use for 1 month) and  
replace dead batteries with recognized name brand AA Alkaline batteries.  
ii  
 
Classification:  
Protection against electric shock: Internally powered equipment.  
Protection against water: Ordinary equipment  
Mode of Operation: Continuous  
Sterilization: See section 6  
Safety of application in the presensence of a flammable anesthetic  
mixture: See section 8.1  
FAILURE TO COMPLY WITH THESE WARNINGS AND CAUTIONS  
COULD RESULT IN INSTRUMENT DAMAGE AND POSSIBLY  
JEOPARDIZE THE WELL BEING OF THE PATIENT AND/OR HEALTH  
CARE PROFESSIONAL.  
iii  
 
TABLE OF CONTENTS  
1. SYSTEM OVERVIEW ............................................. 1  
1.1  
1.2  
1.3  
Base Unit Description ................................ 1  
Components Description ......................... 2  
MAX-250 Oxygen Sensor ............................. 4  
2. SET-UP PROCEDURE ......................................... 5  
2.1  
2.2  
Battery Installation ..................................... 5  
2ꢀ  
Calibrating The MAXO Analyzer ........... 5  
2.2.1 Before You Begin ...........................  
2ꢀ  
5
6
2.2.2 To Calibrate The MAXO Analyzer  
2.2.3 Automatic Calibration To Room Air. 7  
2.2.4 Factors Influencing Calibration .....  
8
3. OPERATION INSTRUCTIONS .............................. 9  
4. SENSOR REMOVAL AND REPLACEMENT ......... 9  
5. PROBLEM SOLVING ............................................... 11  
6. CLEANING AND MAINTENANCE ......................... 11  
7. SPECIFICATIONS ................................................ 12  
7.1  
7.2  
Base Unit Specifications ......................... 12  
Sensor Specifications .............................. 12  
8. APPLICATIONS  
.................................................. 13  
8.1  
8.2  
Exposure to Anesthetic Gases ............... 13  
Calibration Techniques in Pressurized  
Systems .................................................... 13  
Calibration Errors .................................... 14  
Atmospheres of High Humidity ............... 14  
8.3  
8.4  
9. SPARE PARTS AND ACCESSORIES ................. 15  
10.WARRANTY ......................................................... 16  
iv  
 
1. SYSTEM OVERVIEW  
1.1 Base Unit Description  
The MAXO2analyzer (Model OM-25A) provides unparalleled  
performance and reliability, due to an advanced design that includes the  
following features and operational benefits.  
Fast-responding, oxygen-specific, galvanic sensor that achieves  
90% of final value in approximately 15 seconds at room temperature.  
Extra-life oxygen sensor of approximately 900,000 O2 percent hours  
(minimum 2 years in most normal applications).  
Adaptable sample input connection and internal sensor.  
Operation using only 2 AA alkaline batteries (2 X 1.5 Volts) for  
approximately 3000 hours of performance in typical usage. For extra  
extended long life, 2 AA lithium batteries may be used.  
Durable, compact case that permits comfortable, hand-held operation.  
Large, easy-to-read, 3 1/2-digit LCD display for readings in the 0-100%  
range.  
Simple operation and calibration using quick-calibrate key functions.  
Self-diagnostic check of analog and microprocessor circuitry.  
Low battery indication.  
1
 
1.2  
Components Description (please refer to page 3)  
CD Readout  
A
3 1/2-Digit Display- The 3 1/2-digit liquid crystal display (LCD)  
provides direct readout of oxygen concentrations in the range of  
0-100%. It also displays "CAL" when the calibration mode is  
entered.  
1
"%" Sign- The "%" sign is present during normal operation  
when the keypad settings are locked. When the keypad settings  
are unlocked, the "%" sign is not visible. In the calibration mode,  
the "%" sign flashes every second.  
2
Low Battery Indicator- The low battery indicator appears on  
the LCD display when the power supply voltage drops below  
acceptable limits. When the "LOW BAT" icon is visible, batteries  
should be replaced immediately.  
3
Keypad  
B
4
ON/OFF Key- (after Calibration) This key is used to turn  
the instrument on or off. When batteries are installed in  
the unit and the unit is in the power off mode, the display  
will be blank. When the ON/OFF key is pressed once, the unit will  
start to display the oxygen concentration and the keypad is  
activated. If the ON/OFF key is pressed again, the unit reverts to  
the power off mode.  
LOCK/UNLOCK Key- The presence of the "%" sign on the LCD  
readout is an indication that the unit is in its normal  
"LOCKED" state. The unit must be unlocked in order to  
be calibrated. Pressing the LOCK key will unlock the keypad and  
cause the "%" sign to disappear. The unit can then be calibrated  
if desired. If no other keys are pressed within 10 seconds, the  
"%" sign will reappear and the unit will revert to the "LOCKED"  
mode.  
5
CALIBRATE Key- The Unit will force you to Calibrate the  
first time power is applied or the sensor is changed. This is  
indicated on the LCD by the word “CAL”. Pressing the  
6
CALIBRATE key will allow the and arrow keys to calibrate the  
unit. Also when the keypad is unlocked, the CALIBRATE key is  
used in conjunction with the and arrow keys to calibrate the  
unit. When the CALIBRATE key is pressed, "CAL" appears on  
the LCD readout for 1 second and then the measured calibration  
concentration is displayed. The calibration value can then be  
2
 
LCD Readout  
A
1
2
3
7
5
4
6
Keypad  
B
Sample Inlet  
Connection  
C
OM-25A  
3
 
changed using the and arrow keys. During calibration, the  
"%" sign will flash at a once per second rate. When the  
calibration value is set, pressing the CALIBRATE or  
LOCK/UNLOCK key will cause the unit to exit the calibration  
mode and return to normal operation. The unit will also revert to  
normal operation if 10 seconds elapse and no keys are pressed.  
7
and Keys- The and arrow keys are used in  
conjunction with the CALIBRATE key to calibrate the  
unit. Pressing the or key will raise or lower the displayed  
oxygen value in .1% increments. When either of these keys are  
held down for more than 1 second, the display will scroll at a rate  
of .4% per second.  
C
Sample Inlet Connection  
1.3  
MAX-250 Oxygen Sensor  
MAX-250 oxygen sensors offer quick response, stability and extra life on  
the order of 900,000 percent oxygen hours.  
The MAX-250 is a galvanic, partial pressure sensor that is specific to  
oxygen. It consists of two electrodes (a cathode and an anode), a teflon  
membrane and an electrolyte. Oxygen diffuses through the teflon  
membrane and immediately reacts at a gold cathode. Concurrently,  
oxidation occurs electrochemically at the lead anode, generating an  
electrical current and providing a voltage output. Electrodes are immersed  
in a unique gelled weak acid electrolyte which is responsible for the  
sensors long life and motion insensitive characteristic. Since the sensor is  
specific to oxygen, the current generated is proportional to the amount of  
oxygen present in the sample gas. When no oxygen is present, there is  
no electrochemical reaction and therefore, negligible current is produced.  
In this sense, the sensor is self-zeroing.  
CAUTION: The Maxtec MAX-250 oxygen sensor is a sealed  
device containing a mild acid electrolyte, lead (Pb), and lead  
acetate. Lead and lead acetate are hazardous waste  
constituents and should be disposed of properly, or  
returned to Maxtec for proper disposal or recovery.  
CAUTION: Do not use ethylene oxide sterilization. Do not  
immerse the sensor in any cleaning solution, autoclave or  
expose the sensor to high temperatures.  
CAUTION: Dropping or severely jarring the sensor after  
calibration may shift the calibration point enough to require  
recalibration.  
4
 
2. SET-UP PROCEDURE  
2.1 Battery Installation  
All MAXO2analyzer units are powered by two, AA alkaline batteries (2 x  
1.5 Volts) and are shipped without the batteries installed. The battery  
compartment is accessible from the back side of the unit. To install the  
batteries:  
1) With the thumb, press down on the center of the battery compartment  
cover and slide the cover off of the instrument case.  
2) Install the two, AA, alkaline batteries (2 x 1.5 Volts) in the unit,  
observing the orientation shown on the label inside the compartment.  
3) Slide the battery compartment cover back onto the case. Make sure  
the tabs on the cover snap into position, securing the cover flush  
against the case.  
When batteries are installed in the MAXO2analyzer, the unit initiates a  
self-diagnostic test. All segments of the LCD readout are turned on for  
approximately 2 seconds. When the diagnostic test is completed  
successfully, the word "OFF" will appear on the display, indicating that the  
unit is ready to be calibrated.  
2ꢀ  
Calibrating the MAXO Analyzer  
2.2  
2.2.1 Before You Begin  
The MAXO2Oxygen Analyzer should be calibrated upon receipt.  
Thereafter, Maxtec recommends calibration on a weekly basis. However,  
more frequent calibration will not adversely affect product performance.  
More frequent calibration is required when:  
The temperature of the gas stream changes by more than 3 degrees  
Celsius.  
Changes in elevation result in calibration error of approximately 1% of  
reading per 250 feet. In general calibration of the instrument should  
be performed when the geographic elevation at which the product is  
being used changes by more than 500 feet.  
In addition, calibration is recommended if the user is unsure when the last  
calibration procedure was performed or if the measurement value  
displayed is in question.  
5
 
It is best to calibrate the MAXO2analyzer to a known documented  
oxygen concentration at a pressure and flow similar to your clinical  
application. Calibrating the MAXO2analyzer at lower concentrations with  
a known oxygen value is also acceptable and may provide additional  
accuracy if the calibration gas is closer to the environment in which the  
MAXO2analyzer will be used. A “known” value of oxygen is defined as  
an oxygen source which has a traceable certificate and / or USP  
certification.  
Note: Before beginning calibration the MAX-250 sensor must be in  
thermal equilibrium. You may also need to be aware of other factors  
which affect device calibration values. For more information, refer to  
“Factors Influencing Calibration”, section 2.2.4 in this manual.  
2.2.2 To Calibrate the MAXO2Analyzer  
1) Connect the sample hose to the barbed fitting on the bottom of the  
unit.  
2) Attach the other end of the sample hose to the source of the known  
oxygen concentration and initiate flow of the calibration gas to the unit  
(2 liters per minute is recommended).  
3) Using the ON/OFF key, make sure the unit is in the power on mode.  
4) Allow the oxygen reading to stabilize. This will normally take about  
30 seconds or more.  
5) Press the LOCK/UNLOCK key to unlock the keypad. “UL” will  
appear on the display for about 1 second and then the "%" sign will  
disappear from the display.  
6) Press the CALIBRATE key on the keypad. The word "CAL" will  
appear on the display for about 1 second and then the "%" sign will  
start to flash.  
7) Use the and arrow keys to adjust the displayed oxygen  
concentration to the level of the known concentration. Pressing the  
arrow keys changes the value in .1% increments. If the keys are held  
down for more than 1 second the display will scroll at a rate of .4%  
per second.  
Note: If 10 seconds elapse between key actuations, the system will  
store the latest calibration value and will revert to normal operation.  
If this occurs inadvertently, simply repeat the calibration procedure.  
6
 
8) When the calibration value is set, press the CALIBRATE or  
LOCK/UNLOCK key again to accept the calibration setting and  
return to normal operation.  
Note: If the message "CAL", followed by the message "Er" flashes  
on the display after entering the desired calibration value, the  
system has determined that the entered value will not allow  
operation within the specified output range of the sensor. This  
situation may occur if:  
a) the operator has inadvertently entered the wrong concentration  
for the calibration gas.  
b) the concentration of the calibration gas is not correct.  
c) the sensor is in need of replacement.  
d) the operator attempted to adjust the analyzer before allowing  
sufficient time for the calibration gas to purge out the previous  
sample.  
e) the flow and pressure of the calibration gas was not properly  
regulated.  
Check these items and repeat calibration. If calibration error  
continues to occur, contact the service department of the distributor  
from which the unit was purchased, or you may call Maxtec's  
Customer Service Department directly.  
2.2.3 Automatic Calibration to Room Air  
The MAXO2analyzer can quickly be calibrated to room air (20.9%) using  
a quick-key shortcut command. This function saves time by setting the  
calibration value to 20.9% without scrolling the display. To use this  
function:  
1) Introduce room air to the sensor at a rate of 1-5 liters per minute  
(2 liters per minute is recommended) and allow the reading to  
stabilize.  
2) Press the LOCK/UNLOCK key to unlock the keypad.  
3) Press and hold down the CALIBRATE key. When the "%" sign  
starts to flash, press the arrow key to set the calibration value to  
20.9%.  
7
 
4) Release both the CALIBRATE key and the key.  
The unit will automatically enter the “LOCKED” condition and return to  
normal operation.  
2.2.4 Factors Influencing Calibration  
2
The primary factors influencing the MAXO analyzer are temperature,  
pressure, and humidity.  
Effects of Temperature  
The MAXO2analyzer will hold calibration and read correctly within ±3%  
when in thermal equilibrium within the operating temperature range. The  
device must be thermally stable when calibrated and allowed to thermally  
stabilize after experiencing temperature changes before readings are  
accurate. For these reasons, the following is recommended:  
1) Allow adequate time for the sensor to equilibrate to a new ambient  
temperature.  
2) For best results, perform the calibration procedure at a temperature  
close to the temperature where analysis will occur.  
Pressure Effect  
Readings from the MAXO2analyzer are proportional to the partial  
pressure of oxygen. The partial pressure of Oxygen (PO2) is equal to the  
percentage of oxygen (%O2) times the absolute pressure (AP) at which  
the sample enviroment is measured. (PO2=%O2 x AP). Thus the readings  
are proportional to the concentration if the pressure is held constant. Flow  
rate of sample gas can affect pressure at the sensor in that back pressure  
at the sensing point may change. For these reasons, the following is  
recommended:  
1) Calibrate the MAXO2analyzer at the same pressure as the sample  
gas.  
2) If sample gases flow through tubing, use the same apparatus and  
flow rates when calibrating as when measuring.  
3) The MAXO2analyzer oxygen sensor has been validated at  
pressures up to 2 atmospheres absolute. Calibration or operation  
above this pressure is beyond the intended use.  
8
 
Humidity Effect  
Humidity has no effect on the performance of the MAXO2analyzer other  
than diluting the gas, as long as there is no condensation. Depending on  
the humidity, the gas may be diluted by as much as 4%, which  
proportionally reduces the oxygen concentration from the dry  
concentration. Environments where condensation may occur are to be  
avoided since condensate may obstruct passage of gas to the sensing  
surface, resulting in erroneous readings and slower response time. For  
this reason avoid usage in environments greater than 95% relative  
humidity.  
3. OPERATION INSTRUCTIONS  
To check the oxygen concentration of a sample gas: (after the unit has  
been calibrated)  
1) Connect the sample hose to the barbed fitting on the bottom of the  
unit.  
2) Attach the other end of the sample hose to the sample gas source  
and initiate flow of the sample to the unit at a rate of 1-5 liters per  
minute (2 liters per minute is recommended).  
3) Using the ON/OFF key, make sure the unit is in the power on mode.  
4) Allow the oxygen reading to stabilize. This will normally take about  
30 seconds or more.  
4. SENSOR REMOVAL AND REPLACEMENT  
The OM-25A is shipped with a new MAX-250 oxygen sensor installed.  
Although the sensor has a very long expected life, eventually the sensor  
will require replacement. Removing or installing a sensor, when  
necessary, is a very simple procedure. To remove and install a new  
sensor:  
1) With the front of the analyzer facing downward and the bottom facing  
away from you, press down with both thumbs on the center of the  
battery compartment cover and slide the cover off.  
2) Remove the white barb fitting by turning the barb counter-clockwise.  
7
A /16” wrench may be needed to aid in the removal.  
9
 
3) Remove the expired sensor from the sensor compartment and  
carefully pull apart the small white connector that connects the black  
and red sensor wires to the analog input wiring.  
NOTE: The sensor contains lead and lead acetate, be sure to  
dispose of expired sensors in accordance with hospital, local, state  
and federal regulations.  
4) Remove the new sensor from the package and remove the protective  
film from the sensor face.  
5) Attach the new MAX-250 sensor connector to the MAXO2analyzer  
input connector. The connector halves are keyed for proper  
orientation.  
6) Position the sensor in the sensor compartment with the threaded end  
of the sensor toward the bottom of the unit and the red and black  
wires in the upward position, with the connectors tucked in the  
compartment space on the right.  
7) Replace the barb fitting in the bottom of the case by turning the barb  
clockwise with a 7/16” wrench. The barb fitting needs to be tightened  
firmly against the bottom of the sensor.  
8) Slide the battery compartment cover back onto the case. Make sure  
the tabs on the cover snap into position.  
9) Wait approximately 20 minutes for the sensor to reach equilibrium.  
10) Calibrate the new sensor.  
NOTE: If the analyzer is on when the sensor is detached and  
replaced, the analyzer will automatically force a re-calibration. The  
display will read “CAL”.  
10  
 
5. PROBLEM SOLVING  
If the "LOW BAT" icon is displayed on the LCD readout at any time,  
the batteries should be replaced as soon as possible.  
When the unit is in the power on mode and the LCD displays "000%,"  
the sensor is not connected properly. Check the sensor connection  
and if the condition persists, contact the Maxtec Customer Service.  
If, at any time, "ErX" (i.e. Er1, Er4, etc.) appears on the LCD readout,  
contact the Maxtec Customer Service.  
6. CLEANING AND MAINTENANCE  
When cleaning or disinfecting the MAXO2analyzer, take appropriate  
care to prevent any solution from entering the instrument.  
The MAXO2analyzer’s surface may be cleaned using a mild  
detergent and a moist cloth.  
The MAXO2analyzer may be disinfected using standard topical  
disinfectants.  
The MAXO2analyzer is not intended for steam, ethylene oxide or  
radiation sterilization.  
Store the MAXO2analyzer in a temperature similar to its ambient  
environment of daily use.  
11  
 
7. SPECIFICATIONS  
7.1 Base Unit Specifications  
Measurement Range: 0.0-100%  
Resolution:  
0.1%  
Accuracy and Linearity: ±1% of full scale at constant temperature, R.H.  
and pressure when calibrated at full scale.  
Total Accuracy:  
Response Time:  
Warm-up Time:  
±3% Actual Oxygen Level over full operating  
temperature range.  
90% of final value in approximately 15 seconds at  
23C.  
none required  
Operating Temperature: 15C - 40C (59F - 104F)  
Storage Temperature: -15C - 50C (5F - 122F)  
Humidity:  
Power Requirements: 2, AA Alkaline batteries (2 x 1.5 Volts)  
Battery Life: approximately 3000 hours in typical use  
Low Battery Indication: "LOW BAT" icon displayed on LCD  
Sensor Type: Maxtec MAX-250 galvanic fuel cell  
Expected Sensor Life: >900,000% O2 Hours  
Over 2 years in typical applications  
0-95% (non-condensing)  
Dimensions:  
3.5"(W) x 5.5"(H) x 1.5"(D) [89mm x 140mm x  
38mm]  
Weight:  
approximately .92 lbs. (417g)  
7.2 Sensor Specifications  
Type:  
Life:  
galvanic fuel sensor (0-100%)  
2 years in typical applications  
Interferent  
Volume % Dry  
Interference in O2%  
Nitrous Oxide  
Carbon Dioxide  
Halothane  
Enflurane  
Isoflurane  
Helium  
75%  
10%  
5%  
5%  
5%  
70%  
15%  
6%  
<2%  
<2%  
<2%  
<2%  
<2%  
<2%  
<2%  
<2%  
Desflurane  
Sevoflurane  
12  
 
8. APPLICATIONS  
8.1 Exposure to Anesthetic Gases  
Because of the unique chemistry of the oxygen sensors provided with the  
MAXO2analyzer, there are no significant effects when exposed to  
commonly used anesthetic gases, however, the analyzer is not designed  
for exposure to flammable gas mixtures. (See WARNING page i)  
8.2 Calibration Techniques in Pressurized Systems  
Similar to other oxygen sensors, the MAX series sensors measure the  
partial pressure of oxygen in a gas stream. This is correlated to read  
“percent oxygen” on the MAXO2analyzer. It is important to note that the  
sensor output is directly proportional to the pressure of oxygen. Thus,  
one must take into consideration the effect of exposing the sensor to  
various gas sample pressures.  
For example, if an analyzer is calibrated to read 20.9% in ambient air  
(atmospheric pressure) and then exposed to a pressurized gas sample  
containing a known concentration of oxygen, the analyzer will display a  
reading greater than the actual oxygen percentage. This is because the  
analyzer was originally calibrated at atmospheric pressure (0 psig) then  
exposed to a higher pressure sample (eg, 5 psig). The greater the  
difference in pressure, the greater the difference in sensor signal (oxygen  
reading on the analyzer).  
By the same token, if an analyzer is calibrated on a pressurized gas  
sample containing a known concentration of oxygen and then exposed to  
ambient air (atmospheric pressure), the analyzer will display a reading  
less than the actual oxygen percentage.  
To avoid confusion, the analyzer can be calibrated at a single point on a  
gas stream similar to the application. If, for example, the purpose of the  
analyzer is to measure oxygen in a concentrator or anesthesia  
application, the optimal results may be attained by calibrating the  
instrument on a gas of similar concentration and pressure. This would  
typically be done by connecting to a cylinder of a known high  
concentration of oxygen calibration gas and adjusting the flow and  
pressure to match the application before calibrating the instrument.  
13  
 
8.3 Calibration Errors  
The MAXO2analyzers have a self test feature built into the software to  
detect faulty calibrations. During calibration, if the signal from the oxygen  
sensor is outside the limits stored within the instrument’s memory, a  
flashing “CAL Er” is displayed. The error code is displayed to indicate  
that either the sensor should be replaced or that there is a fault in the  
calibration process. A few simple hints can prevent calibration errors.  
If you try to adjust the analyzer display before the reading has stabilized,  
the “CAL Er” may appear. For example, if the analyzer had just been  
calibrated on a known high concentration of oxygen source gas and then  
exposed to ambient air, you should wait until the reading has stabilized. If  
you try to adjust the display to read 20.9% before the sample line has  
cleared of high concentration O2, the sensor may actually be exposed to  
residual high % oxygen. The signal from the sensor would still be high  
and considered “out of spec” for air, thus resulting in a “CAL Er”. The  
proper procedure is to wait for the reading to stabilize before adjusting the  
display. This may take 30 seconds or more.  
8.4 Atmospheres of High Humidity  
The MAXO2analyzer can be used in applications where the relative  
humidity of the sample gas ranges from 0 to 95%, non-condensing.  
However, it should be noted that water vapor exerts its own pressure in  
the same manner as oxygen does in a sample gas stream.  
For example, if the MAXO2analyzer is calibrated in dry gas and then the  
gas is humidified, the analyzer will correctly display a reading which is  
slightly lower than previously displayed. This is due to the dilution of  
oxygen in the sample gas by water vapor.  
Gas streams of high humidity may tend to condense on the sensor.  
Condensation on the sensor may eventually affect performance. For this  
reason, it is recommended that the unit be used in a vertical position, with  
the barb fitting pointing downward to prevent condensate from flowing  
onto the sensing surface.  
14  
 
9. SPARE PARTS AND ACCESSORIES  
Part Number  
Item  
R125P01-002  
R212P91  
R212P17  
MAX-250 Internal Sensor  
Battery Cover  
Keypad  
R212P10  
LCD Display  
R212P30-002  
PCBA Board  
Accessories  
R213P02  
R213M15  
R213M66  
Monitor/Analyzer Protective Carrying Case  
OM-25A Operating Instructions  
Technical Service Manual  
Although normal usage will not require repair, Maxtec will make available,  
on request, diagrams, descriptions and instructions to assist user’s  
appropriately qualified technical personnel in repairing and replacing  
broken or worn components.  
15  
 
10. WARRANTY  
The MAXO2Analyzer is designed for medical oxygen delivery equipment  
and systems. Under normal operating conditions, Maxtec warrants the  
MAXO2Analyzer to be free from defects of workmanship or materials for  
a period of two (2) years from the date of shipment from Maxtec, provided  
that the unit is properly operated and maintained in accordance with  
Maxtec’s operating instructions. Based on Maxtec’s product evaluation,  
Maxtec's sole obligation under the foregoing warranty is limited to making  
replacements, repairs, or issuing credit for equipment found to be  
defective. This warranty extends only to the buyer purchasing the  
equipment directly from Maxtec or through Maxtec's designated  
distributors and agents as new equipment.  
Maxtec warrants the MAX-250 oxygen sensor in the MAXO2Analyzer to  
be free from defects in material and workmanship for a period of two (2)  
years from Maxtec's date of shipment in a MAXO2unit. Should a sensor  
fail prematurely, the replacement sensor is warranted for the remainder of  
the original sensor warranty period.  
Routine maintenance items, such as batteries, are excluded from  
warranty. Maxtec and any other subsidiaries shall not be liable to the  
purchaser or other persons for incidental or consequential damages or  
equipment that has been subject to abuse, misuse, mis-application,  
alteration, negligence or accident. THESE WARRANTIES ARE  
EXCLUSIVE AND IN LIEU OF ALL OTHER WARRANTIES, EXPRESSED  
OR IMPLIED, INCLUDING WARRANTY OF MERCHANTABILITY AND  
FITNESS FOR A PARTICULAR PURPOSE.  
16  
 
 
Maxtec, Inc.  
6526 South Cottonwood Street  
Salt Lake City, UT 84107  
General Tel: 801-266-5300  
Toll Free Dial: 800-748-5355  
FAX: 801-270-5590  
 

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