MaxTech Oxygen Equipment OM 25ME User Manual

®
OXYGEN  
MONITOR  
MODEL  
OM-25ME  
(OM-25ME-L)  
USER’S GUIDE  
AND  
OPERATING  
INSTRUCTIONS  
R213M05 Rev. H  
manufactured by:  
®
 
Manufacturer: Maxtec, Inc  
European Representative  
Airox S.A.  
Parcd’activities Pau-Pyrenees  
L’echangeur BP833  
64008 PAU Cedex  
France  
i
 
PREFACE  
This manual describes the function, operation and maintenance of the  
Maxtec Model OM-25ME and OM-25ME-L oxygen monitors. Notes are  
included where differences may occur between the two monitors. As  
members of Maxtec's MAXO2line of oxygen analyzers and monitors, the  
OM-25ME utilizes the Maxtec MAX-250E oxygen sensor and is  
engineered for fast response, maximum reliability and stable  
performance. The OM-25ME is designed primarily for continuous  
monitoring of oxygen levels delivered by medical oxygen delivery  
equipment and respiratory care systems. Adjustable high and low level  
alarm setpoints make the OM-25ME ideal for use in neo-natal,  
anesthesia, and respiratory care.  
THANK YOU  
Thank you for your purchase of a Maxtec MAXO2oxygen monitor. 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  
monitor, all operation and maintenance must be performed in  
accordance with this manual. Please read the manual thoroughly  
before using the monitor 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 Monitor (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, flow diverter, and “T” adapter may be allowed to  
contact such a gas mixture.  
ii  
 
To avoid explosion, do not operate the Oxygen monitor in the presence of  
flammable anesthetics or in an atmosphere of explosive gases. Operating  
the oxygen monitor in flammable or explosive atmospheres may result in  
fire or explosion.  
Never allow an excess length of cable near the patient’s head or neck, as  
such could result in strangulation. Secure excess cable to the bed rail or  
suitable object.  
Never use a MAXO2 monitor with a cable that appears worn, cracked or  
has damaged insulation  
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 monitor’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.  
iii  
 
The OM-25ME-L™ oxygen monitor has been manufactured with a low  
alarm setting adjustable down to 15% This change is within the  
guidelines set forth in ASTM Specification F1462-93. The OM-25ME-L™  
is labeled to indicate this feature.  
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 aesthetic  
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.  
iv  
 
TABLE OF CONTENTS  
1. SYSTEM OVERVIEW ...........................................  
1
1
2
1.1  
1.2  
1.3  
Base Unit Description ..............................  
Components Description ........................  
MAX-250E Oxygen Sensor .......................... 6  
2. SET-UP PROCEDURE ......................................... 7  
2.1  
2.2  
Battery Installation ................................... 7  
Calibrating the MAXO2Monitor ................. 7  
2.2.1 Before You Begin .............................  
2.2.2 To Calibrate the MAXO2Monitor ...  
2.2.3 Automatic Calibration to Room Air  
7
8
9
2.2.4 Factors Influencing Calibration ...... 10  
3. OPERATING INSTRUCTIONS ............................ 12  
3.1  
Alarm Setting Procedure ........................ 12  
3.1.1 Low Alarm Setting ........................ 12  
3.1.2 High Alarm Setting ....................... 12  
Basic Operation ....................................... 13  
Alarm Conditions ..................................... 13  
3.2  
3.3  
4. SENSOR REMOVAL AND REPLACEMENT ........ 14  
5. PROBLEM SOLVING ............................................. 15  
6. CLEANING AND MAINTENANCE ......................... 15  
7. SPECIFICATIONS ................................................ 16  
7.1  
7.2  
Base Unit Specifications ......................... 16  
Sensor Specifications ............................. 16  
8. APPLICATIONS  
.................................................. 17  
8.1  
8.2  
Exposure to Anesthetic Gases ............... 17  
Calibration Techniques in Pressurized  
Systems .................................................... 17  
Calibration Errors .................................... 18  
Atmospheres of High Humidity ............... 18  
8.3  
8.4  
9. SPARE PARTS AND ACCESSORIES .................... 20  
10.WARRANTY ......................................................... 21  
v
 
1. SYSTEM OVERVIEW  
1.1 Base Unit Description  
The MAXO2(Model OM-25ME) 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 applications).  
External probe with 10 ft., extendible cable and diverter fitting for  
standard 15 mm "T" adapter.  
Operation using 2 AA alkaline batteries (2 x 1.5 volts) for  
approximately 3000 hours of performance in typical usage (not in  
alarm conditions). For extra extended long life, 2 AA lithium  
batteries may be used.  
Durable, compact case that weighs less than 1 pound and  
permits comfortable, hand-held operation.  
Large, easy-to-read, 3 1/2-digit LCD display for readings in the 0-100%  
range.  
Adjustable high-level and low-level alarming capability with flashing  
LED and audible indication of alarm conditions.  
Simple operation and calibration using quick-calibrate key functions.  
Self-diagnostic check of analog and microprocessor circuitry.  
Low battery indication.  
1
 
1.2  
A
Components Description (please refer to page 3)  
LCD Readout  
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- In the calibration mode, the "%" sign flashes every  
second.  
2
3
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.  
LOCKED Status Indicator- The presence of the "LOCKED"  
icon on the LCD readout is an indication that the unit is in its  
normal "LOCKED" state. The unit must be unlocked, using the  
LOCK key, in order to be calibrated or to change the high and low  
alarm settings.  
4
5
Low Alarm Indicator- The low alarm setting is displayed at all  
times just below the "LOW" icon on the LCD readout. The  
indicated value represents the oxygen percentage at which the  
low alarm will be activated. In the low alarm set mode, the  
"LOW" icon will flash at a 1 second rate. In a low alarm  
condition, the low alarm value will flash in conjunction with the  
low alarm light emitting diode (LED).  
High Alarm Indicator- The high alarm setting is displayed at all  
times just below the "HIGH" icon on the LCD readout. The  
indicated value represents the oxygen percentage at which the  
high alarm will be activated. In the high alarm set mode, the  
"HIGH" icon will flash at a 1 second rate. In a high alarm  
condition, the high alarm value will flash in conjunction with the  
high alarm LED.  
6
7
Threaded Mounting Bushing- Threads to Table Top Swivel  
Stand. Also may be used with many third party camera mounting  
accessories.  
2
 
1
LCD Readout  
2
A
5
3
6
Alarm 8  
LEDs  
B
9
4
15  
13  
10  
14  
16  
12  
11  
7
C
18  
Keypad  
17  
D
External  
Probe  
OM-25ME  
3
 
Alarm LEDs  
B
8
Low Alarm LED- In a low alarm condition, the red "LOW  
ALARM" LED will flash each second, accompanied by the alarm  
beeper.  
High Alarm LED- In a high alarm condition, the red "HIGH  
ALARM" LED will flash each second, accompanied by the alarm  
beeper.  
9
Keypad  
C
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.  
10  
LOCK/UNLOCK Key- Pressing the LOCK/UNLOCK key  
will unlock the keypad and cause the ”LOCKED" icon to  
disappear from the LCD readout. The unit can then be calibrated  
and alarm settings can be changed if desired. If no other keys  
are pressed within 10 seconds, the "LOCKED" icon will reappear  
and the unit will revert to the "LOCKED" mode. When the unit is  
in the unlocked state, pressing the LOCK/UNLOCK key will also  
cause the "LOCKED" icon to reappear.  
11  
12  
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  
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  
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.  
4
 
and Keys- The and arrow keys are used in  
13  
14  
conjunction with the CALIBRATE key to calibrate the unit or in  
conjunction with the LOW SET and HIGH SET keys to adjust the alarm  
settings. When used after pressing the CALIBRATE key, 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. When used  
after pressing either the LOW SET or HIGH SET keys, pressing the or  
key will raise or lower the displayed alarm setting in 1% increments. In  
the alarm set mode, holding these keys down for more than 1 second  
will cause the display to scroll at a rate of 4% per second.  
LOW SET Key- When the keypad is unlocked, pressing the  
LOW SET key will cause the "LOW" icon to flash. The low  
alarm setting can then be changed using the and arrow keys. When  
the low alarm value is set and the LOW SET or LOCK/UNLOCK key is  
pressed again, the unit exits the alarm set mode and returns to normal  
operation. The unit will also revert to normal operation (storing the most  
recent alarm value) if 10 seconds elapse and no keys are pressed. The  
OM-25ME alarm setting is adjustable down to 18%. The OM-25ME-L low  
alarm setting is adjustable to 15%.  
HIGH SET Key- When the keypad is unlocked, pressing the  
HIGH SET key will cause the "HIGH" icon to flash. The high  
15  
16  
alarm setting can then be changed using the and arrow keys. When  
the high alarm value is set and the HIGH SET or LOCK/UNLOCK key is  
pressed again, the unit exits the alarm set mode and returns to normal  
operation. The unit will also revert to normal operation (storing the most  
recent alarm value) if 10 seconds elapse and no keys are pressed.  
SILENT Key- In an alarm condition, pressing the SILENT key will  
deactivate the alarm beeper, but the alarm LED and display will  
continue to flash. In 120 seconds, the alarm beeper will sound again.  
This process will be repeated until the alarm condition is cancelled. For  
an alarm condition to be cancelled, the concentration must be .1% higher  
than the alarm setting (in the presence of a low alarm condition) or .1%  
lower than the alarm setting (in the presence of a high alarm condition).  
External Probe  
D
Sensor with Diverter- The sensor (with diverter) is designed to fit  
industry standard, 15 mm I.D. "T" adapters.  
17  
18  
Extendible Cable- The extendible cable allows the sensor to be  
positioned up to 10 feet from the side of the unit.  
5
 
1.3  
MAX-250E Oxygen Sensor  
MAX-250E oxygen sensors offer quick response, stability and extra life on  
the order of 900,000 percent hours.  
The MAX-250E 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 electrochemically at a gold cathode.  
Concurrently, oxidation occurs electrochemically at a 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-250E 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 for 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.  
!
CAUTION: The flow diverter for the sensor is for use with  
flowing gases only. Do not use the diverter when  
performing static sampling, such as in incubators, oxygen  
tents, oxygen hoods, etc.  
!
6
 
2. SET-UP PROCEDURE  
2.1 Battery Installation  
All MAXO2units 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 MAXO2, the unit initiates a self-  
diagnostic test. All segments of the LCD readout are turned on for  
approximately 2 seconds. On OM-25ME units, the alarm beeper sounds  
and the high and low alarm LEDs are illuminated. When the diagnostic  
test is completed successfully, the word "CAL" will appear on the display,  
indicating that the unit is ready for calibration.  
2ꢀ  
Calibrating the MAXO Monitor  
2.2  
2.2.1 Before You Begin  
A protective film covering the threaded sensor face must be removed; wait  
approximately 20 minutes for the sensor to reach equilibrium. Next, the  
MAXO2Oxygen Monitor should be calibrated. Thereafter, Maxtec  
recommends calibration on a weekly basis. However, more frequent  
calibration will not adversely affect product performance.  
More frequent calibration is recommended when:  
Calibration of the instrument should be performed 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  
7
 
be performed when the geographic elevation at which the product is being  
used changes by more than 500 feet.  
The sensor is best calibrated while mounted in the industry standard,  
15mm I.D. “T” adapter. As in normal operation, the oxygen sensor  
responds best when installed in a vertical position with the sensor facing  
down.  
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.  
It is best to calibrate the MAXO2Monitor to a known documented oxygen  
concentration at a pressure and flow similar to your clinical application.  
Calibrating the MAXO2at 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 MAXO2will 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-250E 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 and Performance” in this manual.  
2.2.2 To Calibrate the MAXO2Monitor  
1) Place the external probe in a stream of gas of known oxygen  
concentration. Expose the sensor to the calibration gas at a  
regulated pressure and flow.  
2) Using the ON/OFF key, make sure the unit is in the power on mode.  
3) Allow the oxygen reading to stabilize. This will normally take about  
30 seconds or more.  
4) Press the LOCK/UNLOCK key to unlock the keypad. The  
"LOCKED" icon will disappear from the display.  
5) 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.  
8
 
6) 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.  
7) 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 monitor 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 MAXO2Monitor 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.  
9
 
To use this function:  
1) Place the external probe in room air.  
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%.  
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 Monitor are temperature,  
pressure, and humidity.  
Effects of Temperature  
The MAXO2Monitor 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 reading are  
accurate. For these reasons, the following is recommended:  
1) Allow adequate time for the sensor to equilibrate to a new ambient  
temperature.  
2) When used in a breathing circuit, place the sensor upstream of the  
heater.  
3) For best results, perform the calibration procedure at a temperature  
close to the temperature where analysis will occur.  
10  
 
Pressure Effect  
Readings from the MAXO2Monitor 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 MAXO2Monitor 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 MAXO2Monitor oxygen sensor has been validated at pressures  
up to 2 atmospheres absolute. Calibration or operation above this  
pressure is beyond the intended use.  
Humidity Effect  
Humidity has no effect on the performance of the MAXO2Monitor 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, the following is recommended:  
1) Avoid usage in environments greater than 95% relative humidity.  
2) When used in a breathing circuit, place the sensor upstream of the  
humidifier.  
11  
 
3. OPERATING INSTRUCTIONS  
3.1 Alarm Setting Procedure  
3.1.1 Low Alarm Setting  
To adjust the low alarm setting:  
1) Press the LOCK/UNLOCK key to unlock the keypad.  
2) Press the LOW SET key. The "LOW" icon will start to flash.  
3) Use the and arrow keys to set the low alarm to the desired  
value. 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 low alarm value and will revert to normal operation.  
If this occurs inadvertently, simply repeat the alarm setting  
procedure.  
The low alarm value cannot be set lower than 18%, nor can it be set  
closer than 1% from the high alarm value due to ASTM specifications  
(special applications requiring alarms below 18% can be accomodated by  
the model OM-25ME-L Monitor). For example, if the high alarm is set at  
25%, the system will not accept a low alarm setting greater than 24%.  
4) When the low alarm value is set, press the LOW SET or  
LOCK/UNLOCK key again to accept the low alarm setting and return  
to normal operation.  
Note: To automatically set the low alarm to 18% without scrolling  
the display, hold the LOW SET key down and press the arrow key  
when the "LOW" icon is flashing.  
3.1.2 High Alarm Setting  
To adjust the high alarm setting:  
1) Press the LOCK/UNLOCK key to unlock the keypad.  
2) Press the HIGH SET key. The "HIGH" icon will start to flash.  
3) Use the and arrow keys to set the high alarm to the desired  
value.  
12  
 
The high alarm value cannot be set closer than 1% from the low alarm  
value due to ASTM specifications. For example, if the low alarm is set at  
50%, the system will not accept a high alarm setting less than 51%.  
Setting the high alarm to 100% turns off or deactivates the high alarm.  
4) When the high alarm value is set, press the HIGH SET key again to  
accept the high alarm setting and return to normal operation.  
Note: To automatically set the high alarm to 50% without scrolling  
the display, hold the HIGH SET key down and then press the arrow  
key when the "HIGH" icon is flashing. To automatically turn off the  
high alarm or set it to 100%, hold the HIGH SET key down and then  
press the arrow key when the "HIGH" icon is flashing.  
3.2 Basic Operation  
To check the oxygen concentration of a sample gas:  
1) Place the external probe in the sample gas stream. When using a  
standard "T" adapter, make sure the sensor is mounted in the adapter  
with the flow diverter pointing downward. This will prevent moisture  
from draining into the sensor membrane.  
Note: It is important that a tight fit exists between the probe and the  
"T" adapter.  
2) Initiate flow of the sample gas to the sensor.  
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.  
3.3 Alarm Conditions  
In the event of either a low alarm or high alarm condition, the  
corresponding LED will begin to flash, accompanied by the alarm beeper.  
Pressing the SILENT key will deactivate the buzzer but the LED and the  
alarm value digits on the display will continue to flash until the alarm  
condition has been rectified. If the alarm condition still exists 120  
seconds after silencing the alarm beeper, the beeper will start to sound  
again.  
A low alarm condition will remain until the actual concentration is .1%  
higher than the low alarm setting. A high alarm condition will remain until  
the the actual concentration is .1% lower than the high alarm setting.  
13  
 
4. SENSOR REMOVAL AND REPLACEMENT  
The OM-25ME is shipped with a new MAX-250E 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) Grasp the sensor in one hand and, with the other hand, unscrew the  
cable connector counter-clockwise at the sensor.  
2) Pull out the cable connector plug from the expired sensor.  
3) Unscrew the flow diverter from the sensor and discard the expired  
sensor.  
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 packaging and remove the  
protective film from the sensor face.  
5) Insert the cable connector plug into the receptacle of the new sensor  
and tighten the cable connector.  
6) Screw the flow diverter onto the new sensor.  
7) Wait approximately 20 minutes for the sensor to reach equilibrium.  
8) Calibrate the new sensor.  
Note: If the monitor is on when the sensor is detached and replaced,  
the monitor will automatically force a re-calibration. The display will  
read “CAL”.  
14  
 
5. PROBLEM SOLVING  
If the "LOW BAT" icon is displayed on the LCD readout at any time,  
the batteries should be replaced as quickly as possible.  
When the unit is in the power on mode and the LCD displays "000%,"  
the sensor is not connected properly. The "ATTACH SENSOR" icon  
will also appear on the display. Check the sensor connection and if  
the condition persists, contact Maxtec's Customer Service  
Department.  
If, at any time, "ErX" (i.e. Er1, Er4, etc.) appears on the LCD readout,  
contact Maxtec's Customer Service Department.  
6. CLEANING AND MAINTENANCE  
When cleaning or disinfecting the MAXO2Monitor, take appropriate  
care to prevent any solution from entering the instrument.  
The MAXO2Monitors surface may be cleaned using a mild  
detergent and a moist cloth.  
The MAXO2Monitor may be disinfected using standard topical  
disinfectants.  
The MAXO2Monitor is not intended for steam, ethylene oxide or  
radiation sterilization.  
Store the MAXO2Monitor in a temperature similar to its ambient  
environment of daily use.  
15  
 
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-250E galvanic fuel cell  
Expected Sensor Life: >900,000% O2 Hours  
over 2 years in typical applications  
0-95% (non-condensing)  
Alarm System:  
high/low alarms, flashing red LEDs, nominal  
2300Hz audible alarm beeper  
Low Alarm Range:  
High Alarm Range:  
18%-99% (>1% lower than high alarm)  
15%-99% (>1% lower than high alarm)OM-25ME-L  
19%-99% (>1% higher than low alarm)  
16%-99% (>1% higher than low alarm)OM-25ME-L  
exact to displayed alarm value  
Alarm Accuracy:  
Dimensions:  
Weight:  
3.5"(W) x 5.5"(H) x 1.5"(D) [89mm x 140mm x 38mm]  
approximately .92 lbs. (417g)  
Cable Length:  
Diverter Fitting:  
10 ft. (3m) fully extended  
fits industry standard, 15 mm "T" adapter  
7.2 Sensor Specifications  
Type:  
Life:  
galvanic fuel sensor (0-100%)  
2 years in typical applications  
Interferent  
Nitrous Oxide  
Carbon Dioxide  
Halothane  
Enflurane  
Isoflurane  
Helium  
Volume % Dry  
Interference in O2%  
75%  
10%  
5%  
5%  
5%  
70%  
6%  
15%  
<2%  
<2%  
<2%  
<2%  
<2%  
<2%  
<2%  
<2%  
Sevoflurane  
Desflurane  
16  
 
8. APPLICATIONS  
8.1 Exposure to Anesthetic Gases  
Because of the unique chemistry of the oxygen sensors provided with the  
MAXO2Monitor, there are no significant effects when exposed to  
commonly used anesthetic gases, however, the monitor 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 Maxtec MAX series sensors measure  
the partial pressure of oxygen in a gas stream. This is correlated to read  
“percent oxygen” on the MAXO2Monitors. 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 a monitor 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 monitor will display a  
reading greater than the actual oxygen percentage. This is because the  
monitor 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 monitor).  
By the same token, if a monitor is calibrated on a pressurized gas sample  
containing a known concentration of oxygen and then exposed to ambient  
air (atmospheric pressure), the monitor will display a reading less than the  
actual oxygen percentage.  
To avoid confusion, the monitor can be calibrated at a single point on a  
gas stream similar to the application. If, for example, the purpose of the  
monitor 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.  
17  
 
8.3 Calibration Errors  
The MAXO2Monitors 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 monitor display before the reading has stabilized,  
the “CAL Er” may appear. For example, if the monitor 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.  
Externally mounted sensors, as found on the OM-25ME or OM-25ME-L  
come equipped with diverter tips. The tips help direct the gas in a “T”  
fitting up to the sensor for analysis. The diverter tips should be only used  
with a flowing gas. When calibrating in a non-flowing environment,  
remove the diverter tip.  
8.4 Atmospheres of High Humidity  
The MAXO2Monitor 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 monitor is calibrated in dry gas and then the gas is  
humidified, the monitor 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.  
This fact is important to note in systems where there exist both “wet” and  
“dry” gas streams such as in a ventilator circuit. If the monitor is  
measuring oxygen on the “dry side” of the ventilator, it will correctly  
indicate an oxygen concentration slightly greater than actually found in the  
“wet side” (delivered to the patient). The water vapor has diluted the gas  
stream.  
18  
 
Additionally, 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 sensor be mounted in a  
vertical position, facing downward to prevent condensate from flowing  
onto the sensing surface.  
19  
 
9. SPARE PARTS AND ACCESSORIES  
Part Number  
Item  
R12503-002  
R212P91  
MAX-250E Sensor  
Battery Cover  
R103P16  
R212P17  
Monitor/Analyzer External Cable  
Keypad  
R212P10  
LCD Display  
R212P30-001  
PCBA Board  
Accessories  
R106P15  
R205P86  
R206P75  
R213P02  
R213P31  
RP16P02  
RP16P10  
R213M05  
R213M66  
Concentrator Adapter for Sensor Probe  
Monitor/Analyzer Wall Mount Bracket  
Monitor/Analyzer Pole Mount Clamp  
Monitor/Analyzer Protective Carrying Case  
Swivel Mount Stand  
“T” Adapter (15 mm I.D.)  
“T” Oxygen Sensor Activator System  
OM-25ME Manual  
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.  
20  
 
10. WARRANTY  
The MAXO2Monitor is designed for medical oxygen delivery equipment  
and systems. Under normal operating conditions, Maxtec warrants the  
MAXO2Monitor 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-250E oxygen sensor in the MAXO2Monitor 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.  
21  
 
 
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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