Maxtec MaxN2+ Nitrogen Analyzer

Company Information

Maxtec

2305 South 1070 West

Salt Lake City, Utah 84119

USA

TEL: (800) 748.5355

FAX: (801) 973.6090

Email: sales@maxtec.com

Website: www.maxtec.com

EC REP: QNET BV, Kantstraat 19, NL-5076 NP Haaren, The Netherlands

CE 0123

Classification

• Protection against electric shock: Internally powered equipment.
• Protection against water: ? IPX1
• Mode of Operation: Continuous
• Sterilization: See section 7.0
• Flammable anesthetic mixture: Not suitable for use in presence of a flammable anesthetic mixture.

Product Disposal Instructions

The sensor, batteries, and circuit board are not suitable for regular trash disposal. Return sensor to Maxtec for proper disposal or dispose according to local guidelines. Follow local guidelines for disposal of other components.

Warranty

The MaxN2+ analyzer is designed for nitrogen delivery equipment and systems. Maxtec warrants the MaxN2+ analyzer to be free from defects of workmanship or materials for a period of 2-years from the date of shipment, provided the unit is properly operated and maintained. Maxtec's sole obligation is limited to making replacements, repairs, or issuing credit for defective equipment. This warranty extends only to the buyer purchasing the equipment directly from Maxtec or its authorized distributors.

Maxtec warrants the oxygen sensor in the MaxN2+ analyzer to be free from defects for a period of 2-years for Nitrogen A & AE and 1-year for Nitrogen A Fast from the date of shipment. If a sensor fails 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 is not liable for incidental or consequential damages or equipment subjected 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.

Warnings

FAILURE TO COMPLY WITH THESE WARNINGS AND CAUTIONS COULD RESULT IN INSTRUMENT DAMAGE AND POSSIBLY JEOPARDIZE THE WELL BEING OF THE USER.

⚠️ Indicates a potentially hazardous situation, if not avoided, could result in death or serious injury.

• Improper use of this device can cause inaccurate oxygen readings, leading to improper treatment, hypoxia, or hyperoxia. Follow the procedures outlined in this user manual.
• Device specified for dry gas only.
• Before use, all individuals using the MaxN2+ Analyzer must become thoroughly familiar with this Operation Manual. Strict adherence to operating instructions is necessary for safe, effective product performance.
• This product will perform only as designed if installed and operated in accordance with manufacturer's operating instructions.
• Use only genuine Maxtec accessories and replacement parts. Failure to do so may seriously impair the analyzer's performance. Repair must be performed by a qualified service technician.
• Calibrate the MaxN2+ Analyzer weekly, or if environmental conditions change significantly (e.g., elevation, temperature, pressure, humidity). Refer to Section 3.0.
• Use of the MaxN2+ Analyzer near devices that generate electrical fields may cause erratic readings.
• If the MaxN2+ Analyzer is exposed to liquids (spills or immersion) or other physical abuse, turn the instrument OFF and then ON to allow its self-test to assure correct operation.
• Never autoclave, immerse, or expose the MaxN2+ Analyzer (including sensor) to high temperatures (>70°C). Never expose the device to pressure, irradiation, vacuum, steam, or chemicals.
• This device does not contain automatic barometric pressure compensation.
• Although the sensor has been tested with various gases (including nitrous oxide, Halothane, Isoflurane, Enflurane, Sevoflurane, Desflurane) and found to have acceptably low interference, the device in its entirety is not suitable for use in the presence of a flammable anesthetic mixture with air or with oxygen or nitrous oxide. Only the threaded sensor face, flow diverter, and “T” adapter may contact such a gas mixture.
• NOT for use with inhalation agents. Operating the device in flammable or explosive atmospheres may result in fire or explosion.

❗ CAUTION: Indicates a potentially hazardous situation, if not avoided, could result in minor or moderate injury and property damage.

• Replace batteries with recognized high-quality AA Alkaline or Lithium batteries. DO NOT use rechargeable batteries.
• If the unit is to be stored (not in use for 1 month), remove batteries to protect from leakage.
• The Maxtec MAX-250 oxygen sensor is a sealed device containing a mild acid electrolyte, lead (Pb), and lead acetate. These are hazardous waste constituents and should be disposed of properly, or returned to Maxtec for disposal or recovery.
• DO NOT use ethylene oxide sterilization.
• DO NOT immerse the sensor in any cleaning solution, autoclave, or expose to high temperatures.
• Dropping the sensor can adversely affect its performance.
• The device will assume a percent oxygen concentration when calibrating. Be sure to apply 100% oxygen, or ambient air concentration during calibration, or the device will not calibrate correctly.

NOTE: This product is latex free.

1.0 System Overview

1.1 Base Unit Description

The MaxN2+ analyzer provides unparalleled performance and reliability due to an advanced design that includes the following features and operational benefits:

• Extra-life oxygen sensor of approximately 1,500,000 O2 percent hours (2-year warranty).
• Durable, compact design for comfortable, hand-held operation and easy cleaning.
• Operation using two AA Alkaline batteries (2 x 1.5 Volts) for approximately 5000 hours of performance with continuous use. For extended life, two AA Lithium batteries may be used.
• Oxygen-specific, galvanic sensor that achieves 90% of final value in approximately 15 seconds at room temperature.
• Large, easy-to-read, 3 1/2-digit LCD display for readings in the 0-100% range.
• Simple operation and easy one-key calibration.
• Self-diagnostic check of analog and microprocessor circuitry.
• Low battery indication.
• Calibration reminder timer alerts the operator with a calibration icon on the LCD display.

1.2 Symbol Guide

The following symbols and safety labels are found on the MaxN2+ analyzer:

• ✔️ Follow instructions for use.
• ⚠️ Warning
• ✅ ETL Certified
• ? Do not throw away. Follow local guidelines for disposal.
• ⚙️ Calibration required
• ❌ Do Not
• ? IPX1 Drip Proof
• ? LOT Lot code/Batch code
• ▶️ On/Off Button
• ⚙️ Calibration Button
• ? Low Battery
• % Percent
• [Manufacturer] Manufacturer
• ?️ REF Catalog Number
• ? SN Serial Number

1.3 Component Identification

Refer to Figure 1 for component identification.

FIGURE 1: MaxN2+ Analyzer Components

• LCD Display
• Keypad
• Sample Inlet Connection

Numbered labels on diagram: 1, 2, 3, 4, 5, 6

1.4 Component Description

A. LCD Display

1. 3 1/2-Digit Display: Provides direct readout of nitrogen concentrations in the range of 0 - 105.0%. Displays error codes and calibration codes.
2. Low Battery Indicator (?): Located at the top of the display, activated when battery voltage is low.
3. "%" Symbol: Located to the right of the concentration number during normal operation.
4. Calibration Symbol (⚙️): Located at the bottom of the display, activates when calibration is necessary.

B. Keypad

1. ON/OFF Key (▶️): Turns the device on or off.
2. Calibration Key (⚙️): Used to calibrate the device. Holding for more than three seconds enters calibration mode.

C. Sample Inlet Connection

Port at which the device is connected to determine oxygen concentration.

1.5 MAX-250 Oxygen Sensor

The MAX-250 Series oxygen sensors are galvanic, partial pressure sensors specific to oxygen. They consist of two electrodes (cathode and anode), a teflon membrane, and an electrolyte. Oxygen diffuses through the membrane and reacts at the gold cathode, while oxidation occurs electrochemically at the lead anode, generating an electrical current and voltage output. The sensor uses a gelled weak acid electrolyte for long life and motion insensitivity. The generated current is proportional to the amount of oxygen present, making the sensor self-zeroing.

2.0 Operating Instructions

2.1 Getting Started

2.1.1 Protect Tape

Before turning on the unit, remove the protective film covering the threaded sensor face. After removal, wait approximately 20 minutes for the sensor to reach equilibrium.

2.1.2 Automatic Calibration

After the unit is turned on, it will automatically calibrate to room air. The display should stabilize and read 79.1%.

CAUTION: The device assumes a percent oxygen concentration during calibration. Ensure 100% oxygen or ambient air concentration is applied for correct calibration.

To check the nitrogen concentration of a sample gas (after unit has been calibrated):

1. Connect the Tygon tubing to the bottom of the analyzer by threading the barbed adapter onto the oxygen sensor. (Refer to FIGURE 2)
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 1-10 liters per minute (2 liters per minute recommended).
3. Using the "ON/OFF" (▶️) key, ensure the unit is powered ON.
4. Allow the nitrogen reading to stabilize. This typically takes about 30 seconds or more.

FIGURE 2: Sample Gas Connection

2.2 Calibrating the MaxN2+ Analyzer

Calibrate the MaxN2+ analyzer upon initial power-up and recommend weekly thereafter. A one-week timer starts with each calibration, indicated by a "▼" reminder icon on the LCD. Calibration is recommended if unsure about the last procedure or measurement value.

Start calibration by pressing the ⚙️ key for more than 3 seconds. The MaxO2+ will automatically detect calibration with 100% oxygen or 20.9% oxygen (normal air). Do not attempt to calibrate to other concentrations.

New calibration is required for compressed air (79.1% N2) when:

• The measured N2 percentage in 79.1% N2 is above 80.1% N2.
• The measured N2 percentage in 79.1% N2 is below 78.1% N2.
• The CAL (⚙️) reminder icon is blinking at the bottom of the LCD.
• You are unsure about the displayed N2 percentage.

A simple calibration can be made with the sensor open to ambient air. For optimum accuracy, Maxtec recommends using a closed-loop circuit with controlled gas flow across the sensor. Calibrate using the same circuit and flow rate as your intended readings.

2.3 Operation with the Flow Restrictor

1. Attach the Barbed Adapter to the MaxN2+ analyzer by threading it onto the bottom of the sensor.
2. Connect the Tygon tube to the barbed adapter.
3. Attach the BC adapter to the other end of the Tygon tube.
4. Connect the inflator hose to the other end of the Tygon tube.
5. If the MaxN2+ analyzer is not already on, press the "ON" (▶️) button.
6. Initiate flow of nitrox to the unit to saturate the sensor. The BC adapter regulates flow and pressure. Allow at least two minutes for the sensor to saturate, although a stable value is usually observed within 30 seconds.
7. The analyzer will look for a stable sensor signal and a good reading, then display the oxygen percentage on the LCD.

3.0 Factors Influencing Accurate Readings

3.1 Elevation Changes

• Changes in elevation result in a reading error of approximately 1% of reading per 250 feet.
• Calibration of the instrument should be performed in general.

3.2 Temperature Effects

The MaxN2+ analyzer maintains calibration and reads correctly within ±3% when in thermal equilibrium within the operating temperature range. The device must be thermally stable when calibrated and allowed to stabilize after temperature changes for accurate readings.

• For best results, perform calibration at a temperature close to where analysis will occur.
• Allow adequate time for the sensor to equilibrate to a new ambient temperature.

CAUTION: "CAL Err St" may result from a sensor that has not reached thermal equilibrium.

3.3 Pressure Effects

Readings are proportional to the partial pressure of oxygen. Partial pressure equals concentration times absolute pressure. Readings are proportional to concentration if pressure is constant.

• Calibrate the MaxN2+ analyzer at the same pressure as the sample gas.
• If sample gases flow through tubing, use the same apparatus and flow rates for calibrating as for measuring.
• The MaxN2+ analyzer oxygen sensor has been tested at pressures up to two atmospheres absolute. Calibration or operation above this pressure is beyond the intended use.

3.4 Humidity Effects

Humidity (non-condensing) dilutes the gas (up to 4%), proportionally reducing oxygen concentration, but the device responds to the actual concentration. Condensation can obstruct the sensing surface, leading to erroneous readings and slower response time.

• Avoid usage in environments greater than 95% relative humidity.

HELPFUL HINT: Dry sensor by lightly shaking moisture out, or flow a dry gas at two liters per minute across the sensor membrane.

4.0 Calibration Errors and Error Codes

The MaxN2+ analyzers have a self-test feature to detect faulty calibrations, sensor failures, and low operating voltage. Actions for error codes:

• E02: No sensor attached
  Open the analyzer, disconnect and reconnect the sensor. Unit should auto-calibrate and read 79.1%. If not, contact Customer Service for possible sensor replacement.
• E03: No valid calibration data available
  Ensure unit has reached thermal equilibrium. Press and hold the Calibration Button (⚙️) for three seconds to manually force a new calibration.
• E04: Battery below minimum operating voltage
  Replace batteries.
• CAL Err St: O2 Sensor reading not stable
  Wait for displayed nitrogen reading to stabilize when calibrating with 100% oxygen. Wait for unit to reach thermal equilibrium (may take up to one half hour if stored outside specified temperature range).
• CAL Err lo: Sensor voltage too low
  Press and hold the Calibration Button (⚙️) for three seconds to manually force a new calibration. If the error repeats more than three times, contact Maxtec Customer Service for possible sensor replacement.
• CAL Err hi: Sensor voltage too high
  Press and hold the Calibration Button (⚙️) for three seconds to manually force a new calibration. If the error repeats more than three times, contact Maxtec Customer Service for possible sensor replacement.
• CAL Err Bat: Battery voltage too low to recalibrate
  Replace batteries.

5.0 Changing the Batteries

Batteries should be changed by service personnel. Use only brand name AA batteries. Insert per orientation marked on the device.

The device indicates battery change needs in two ways:

• The battery icon (?) on the display begins to flash. It will continue until batteries are changed. The unit functions normally for approx. 200 hours.
• A very low battery level triggers error code "E04", and the unit will not function until batteries are changed.

To change batteries:

1. Remove the three screws from the back of the device using a #1 Phillips screwdriver.
2. Gently separate the two halves of the device.
3. Replace batteries from the back half of the case, observing embossed polarity.

NOTE: Incorrect battery installation will prevent contact and operation.

Carefully bring the two halves of the case together, ensuring wires are not pinched between the halves. The gasket separating the halves will be captured on the back case half.

Reinsert the three screws and tighten until snug. (Refer to FIGURE 3)

The device will automatically perform a calibration and begin displaying % of oxygen.

HELPFUL HINT: If the unit does not function, verify that the screws are tight to allow proper electrical connection.

FIGURE 3: Reassembling the Device

6.0 Changing the Oxygen Sensor

6.1 MaxN2+ A (R217P67)

The oxygen sensor may need changing if the device indicates "Cal Err lo" on the display after initiating a calibration.

To change the oxygen sensor:

1. Remove the three screws from the back of the device using a #1 Phillips screwdriver.
2. Gently separate the two halves of the device.
3. Disconnect the oxygen sensor from the printed circuit board by pressing the unlock lever and pulling the connector out of the receptacle. The oxygen sensor can now be replaced from the back half of the case.

HELPFUL HINT: Orient the new sensor by aligning the red arrow on the sensor with the arrow in the back case. A small tab on the back case engages the sensor to prevent rotation. (Refer to FIGURE 4)

NOTE: If the oxygen sensor is installed incorrectly, the case will not close properly and the unit may be damaged when screws are reinstalled.

NOTE: If the new sensor has red tape, remove it and wait 30 minutes before calibrating. Reconnect the oxygen sensor to the connector on the printed circuit board.

Carefully bring the two halves of the case together, positioning wires to avoid pinching. Ensure the sensor is fully inserted and oriented correctly.

Reinsert the three screws and tighten until snug. Verify the unit operates properly.

The device will automatically perform a calibration and begin displaying % of oxygen.

FIGURE 4: Sensor Connection Detail

6.2 MaxN2+ AE (R217P66)

The oxygen sensor may need changing if the device indicates "Cal Err lo" on the display.

1. Unthread the sensor from the cable by rotating the thumbscrew connector counterclockwise and pull the sensor from the connection.
2. Replace the new sensor by inserting the electrical plug from the coiled cord into the receptacle on the oxygen sensor. Rotate the thumbscrew clockwise until snug.

The device will automatically perform a calibration and begin displaying % of nitrogen.

7.0 Cleaning and Maintenance

Store the MaxN2+ analyzer in a temperature similar to its ambient environment of daily use.

The following describes methods to clean and disinfect the instrument sensor and its accessories:

Instrument Cleaning:

• When cleaning or disinfecting the exterior, take care to prevent solution from entering the instrument. Do not immerse unit in fluids.
• The MaxN2+ analyzer surface may be cleaned using a mild detergent and a moist cloth.
• The MaxN2+ analyzer is not intended for steam, ethylene oxide, or radiation sterilization.

Oxygen Sensor:

WARNING: Never install the sensor in a location that will expose it to patient's exhaled breath or secretions, unless you intend to dispose of the sensor, flow diverter, and tee adapter after use.

• Clean the sensor with a cloth moistened with a 65% alcohol/water solution.
• Maxtec does not recommend spray disinfectants as they can contain salt, which may accumulate in the sensor membrane and impair readings.
• The oxygen sensor is not intended for steam, ethylene oxide, or radiation sterilization.

Accessories:

• The threaded barbed adapter may be cleaned by washing with a 65% alcohol/water solution (per manufacturer's instructions). Parts must be thoroughly dry before use.

Due to the variability of cleaning processes, Maxtec cannot provide specific instructions. Refer to the manufacturer's instructions for details.

8.0 Specifications

8.1 Base Unit Specifications

8.2 Sensor Specifications

9.0 MAXN2+ Spare Parts and Accessories

9.1 Standard Replacement Parts and Accessories

9.2 Optional Accessories

9.2.1 Optional Adapters

9.2.2 Mounting Options (requires dovetail R217P23)

9.2.3 Carrying Options

NOTE: Repair of this equipment must be performed by a qualified service technician experienced in repair of portable hand held medical equipment.

Equipment in need of repair shall be sent to:

Maxtec
Customer Service Department
2305 South 1070 West
Salt Lake City, Ut 84119
(Include RMA number issued by Customer Service)