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Guide · Gas detection · MSA ALTAIR 5X how-to

How to calibrate and bump test an MSA ALTAIR 5X: the pump test, zero and span calibration, the calibration check, the GALAXY GX2 option, the end-of-sensor-life warning, how often to calibrate, what the 5X detects, what "COMB" means and what it costs

The ALTAIR 5X is MSA’s pumped multigas detector, reading up to six gases through an integral pump. To calibrate it, in fresh air press the up button for five seconds at the measurement page, confirm ZERO with the power button (SENSOR REFRESH, then ZERO CALIBRATION with a progress bar, then ZERO CALIBRATION PASS), connect the demand flow regulator and cylinder to the pump inlet, and press the power button at SPAN; the display shows SPAN CALIBRATION PASS or FAIL for each sensor. The daily calibration check is the same gas applied in measuring mode with the readings compared to the cylinder label; MSA requires it before each day’s use. This page follows MSA’s operating manual and FAQ step by step.

Bayshore Safety. Industrial safety and PPE supplier since 2017. · Current as of November 2026 · MSA ALTAIR 5X product page (us.msasafety.com, fetched Nov 10 2026); ALTAIR 5X operating manual (10150945 r02, MSHA version: turn-on, calibration check, calibration, GX2, shutdown, troubleshooting and factory-set thresholds); ALTAIR 5X FAQ (0802-85-MC, 11.2022); GALAXY GX2 quick start guide (0818-25-MC)
ALTAIR 5X detectors and the parts this guide namesGas detection selector
MSA 10116924 ALTAIR 5X 4-Gas Monitor, LEL/O2/H2S/CO, Monochrome displayMSA 10116924 ALTAIR 5X 4-Gas Monitor, LEL/O2/H2S/CO, Monochrome displayMSA lists the ALTAIR 5X as measuring up to 6 gases with an integral pump, XCell sensors, a 10-foot drop test and IP65 construction
$3,576.83See the product

Why the 5X has its own page. It is the sample-draw instrument in MSA’s line, the one that tests a manhole, tank or pit from outside before anyone goes in, and its pump, its larger sensor set (SO2, NH3, Cl2, ClO2, HCN, PH3, NO2, CO2 and a PID as configured) and its reactive-gas calibration rules give it questions the 4XR page does not cover. MSA’s operating manual and FAQ answer them, and the parts named in those answers (sampling lines, demand regulators, the reactive-gas maintenance kit, the PID lamp, the GALAXY GX2 stand) are in the band at current prices. The general bump-test guide linked below covers the reasons; this page is the procedure.

The ALTAIR 5X, question by question

Quotations are from the ALTAIR 5X operating manual and FAQ; the price is on each row in the band.

What does the MSA ALTAIR 5X detect, and what is "COMB"?MSA’s page: "capable of measuring up to 6 gases simultaneously and is now available with integrated PID sensor for VOC detection", with UL, CSA, ATEX and IECEx listed as its approvals and IP65 construction. The sensor positions take combustible gas (the catalytic LEL sensor, or an IR methane or IR CO2 sensor), oxygen, and XCell electrochemical sensors for CO, H2S, H2S-LC, SO2, NO2, NH3, Cl2, ClO2, HCN and PH3 as configured, plus the PID on the PID versions. "COMB" on the screen is the combustible channel: the catalytic sensor reading in percent LEL or percent methane by volume, and on an IR unit the IR reading. The manual’s factory set points for it are 0.5 percent CH4 low and 1 percent CH4 high (10 and 20 percent LEL).
How do I use the ALTAIR 5X, from turn-on?Press the power button. The manual lists what follows: a self-test of the alarm LEDs, horn, vibrator and installed sensors; the start-up logo; software version, serial number, company, department and user names; the sampling system safety test (the pump check); the combustible gas type and units; the low, high, STEL and TWA set points; the calibration cylinder settings; the date, the last calibration date and the CAL DUE count if enabled ("CAL DUE; X DAYS", with "CAL DUE, NOW" and an alert at zero, cleared with the power button); the sensor warm-up; and the Fresh Air Setup prompt. If a sensor was changed since the last use, the instrument shows the new sensor list and you must accept it with the power button or the instrument alarms and will not run. Then the main measure page appears; a heart symbol on it means a sensor is approaching or at the end of its life.
How do I bump test an ALTAIR 5X (the calibration check)?Manual section 3.7: "Perform a Calibration Check before each day’s use to verify proper device operation." Equipment: the calibration check cylinder(s), a demand flow regulator and the right tubing (MSA sells kits for reactive and non-reactive gases). Steps: 1. Turn the device on in clean, fresh air. 2. Verify the readings show no gas. 3. Attach the demand regulator to the cylinder. 4. Connect the tubing to the regulator. 5. Attach the calibration tube to the pump inlet. The reading "should be within the limits stated on the calibration cylinder or limits determined by your company"; if not, calibrate (section 3.8). MSA says the check "should only take about one minute" and that the GALAXY GX2 can run it, except for a chlorine dioxide sensor, which must be checked by hand. For an IR methane 100 percent volume sensor MSA caps the daily check gas at 20 percent methane. The FAQ adds that XCell sensors allow "a 10-second bump test" and "60-second LEL, O2, H2S, CO, and SO2 single-bottle span calibration".
How do I calibrate an ALTAIR 5X, step by step?Manual section 3.8, with a demand regulator. If a new sensor or battery was fitted, wait 30 minutes first. Zero: 1. At the normal measurement page press the up button for five seconds; the ZERO screen appears (up again skips to span; the down button runs a Fresh Air Setup only; no button for 30 seconds prompts a span and then returns to measuring). 2. Press the power button to confirm; the display shows SENSOR REFRESH (not shown without a catalytic sensor), then ZERO CALIBRATION with a progress bar, and the combustible reading may show PLEASE WAIT; then ZERO CALIBRATION PASS or FAIL. Only a passed zero leads to the SPAN screen. Span: 1. Connect the tubing from the cylinder regulator to the pump inlet. 2. Press the power button; SPAN CALIBRATION flashes and the bar runs. 3. Read SPAN CALIBRATION PASS or FAIL; the instrument returns to measuring. If a sensor is near end of life, PASS is followed by the heart symbol. Finish: remove the tube from the pump inlet; "the calibration procedure adjusts the span value for any sensor that passes the calibration test. Sensors that fail calibration are left unchanged"; a checkmark symbol stays on the measure page for 24 hours after a successful calibration, manual or GX2. When calibrating with combustible gases above 100 percent LEL, answer Yes to "Span Calibration?" before applying gas; on an IR unit a combustible IR calibration puts the catalytic sensor in LockAlarm, which clears when the device is turned off and on in fresh air (a 100 percent volume methane IR unit recovers by itself).
What if the span fails, and what does the heart symbol mean?The manual: "If a span calibration fails: the Sensor Life Indicator blinks to show a sensor has reached its end-of-life and should be replaced. The device remains in the Sensor Life alarm condition until the up button is pressed", and the symbol keeps blinking until the sensor is replaced or calibrated successfully. But MSA also says span can fail for other reasons and lists them: "sufficient gas remaining in the calibration cylinder, gas expiration date, integrity of calibration tubing/fittings", with the instruction "Reattempt the span calibration before replacing the sensor". The FAQ explains the warning itself: after each calibration a software algorithm estimates each sensor’s remaining life and shows the end-of-life warning four to six weeks ahead; the instrument may keep working while it passes bump tests, and when the sensor output at calibration is too low the unit fails calibration and shows the end-of-life indicator, after which it "should not be used until the sensor is replaced".
How often should an ALTAIR 5X be calibrated?The manual sets the pattern rather than a number: a calibration check before each day’s use, a full calibration "periodically to ensure accuracy and immediately if the device fails the Calibration Check", plus after a sensor change, a battery change or a reactive-gas or IR calibration event. The CAL DUE reminder is user selectable from 1 to 180 days and shows the count at start-up; the GALAXY GX2 ships with a 30-day calibration interval and "bump/cal on fail" on by default, so a failed daily check on the stand turns into a calibration automatically.
What calibration gas does the ALTAIR 5X need, and why are reactive gases different?The quad cylinder for LEL, O2, CO and H2S (1.45 percent CH4, 15 percent O2, 60 ppm CO, 20 ppm H2S; 34 L 10048280 or 58 L 10045035) covers the common four; each other sensor takes its own cylinder at the target value in section 5.4 of the manual, through a demand flow regulator on the pump inlet. The manual’s warning on reactive gases: chlorine, ammonia and chlorine dioxide "have the property of diffusing into the rubber and plastic tubes so that the volume of test gas available in the device would no longer be sufficient to correctly perform device calibration"; MSA requires a special pressure regulator, the shortest possible tubing, tubing of a material that does not absorb the gas (PTFE), and dedicated use, and suggests flowing a whole cylinder through ordinary tubing and marking it for that gas only. The reactive-gas maintenance kit and the PTFE probe and sample line in the band are those parts.
How do I check the pump, and what does the sampling line do?The pump is tested at every turn-on (the sampling system safety test) and the manual has a separate pump verification procedure in section 4.2: block the inlet and confirm the pump alarm. A blocked line or filter trips the pump alarm, and the inlet filter and pump filter are replaced on the maintenance kit schedule. For a test from outside a space the sampling line (3 ft polyurethane, 10 ft, or the hose lengths in the band) or the probe goes on the inlet; the longer the line the longer the draw, so wait for the reading to settle before judging the space. MSA’s FAQ explains why the pump is built in: the overmolded housing shields it, and the 5X "survives a 10-foot drop".
What is the GALAXY GX2 option for the 5X?An automated test stand (manual section 3.9) that runs the calibration check and the calibration for the 5X and writes the record; the GX2 quick start guide describes the touch screen, the SD card for records, electronic cylinder holders that read the RFID tag on MSA cylinders and watch pressure, USB export, optional calibration-sticker printing and the defaults (bump/cal on fail on, 30-day calibration interval, 4-week cylinder expiration warning). A successful GX2 calibration puts the same 24-hour checkmark on the measure page as a manual one. MSA notes the GX2 cannot test a chlorine dioxide sensor.
How do I turn the ALTAIR 5X off, and how long does the battery last?Press and hold the power button; the display blinks "HOLD BUTTON FOR SHUTDOWN" with a progress bar that shows how much longer to hold. The product page states at least 20 hours at room temperature per charge (the MSHA manual’s nominal figure is 17 hours for its battery); the charger fills a depleted pack in under six hours between 10 and 35 °C, its LED red while charging, green when charged and yellow for a fault, and MSA warns never to charge in a hazardous area. A low battery warning repeats every 30 seconds; at battery shutdown the instrument is no longer sensing gas and must come out of service.
What do the error messages mean?Manual section 4.1: ERROR ADC (analog measurement), ERROR MEM (memory), ERROR PROG (program) and ERROR RAM all say "Contact MSA"; LOW BATTERY means recharge or replace as soon as possible; BATTERY ALARM means the device is no longer sensing gas; a device that does not turn on or hold a charge is removed from service and sent to MSA. A sensor missing alarm appears if a sensor is absent or not accepted at start-up.
What is the typical life expectancy of the ALTAIR 5X, and what does it cost?MSA prints sensor figures rather than an instrument life: XCell SO2 four years, NH3 and Cl2 three years, O2 "more than four years" (FAQ), with the end-of-life warning giving four to six weeks of notice; the instrument itself is serviced by sensor, pump filter and battery replacement, all listed below. The price depends on the configuration (which sensors, with or without PID or IR, color and case) and is per part number on each row in the band; the 5X PID is the highest-priced configuration because of the PID sensor and lamp.
Where is the ALTAIR 5X manual, and can I change the language?MSA publishes the operating manual on the ALTAIR 5X product page under documents, which our product pages link; the version this guide follows is 10150945 r02. The FAQ states the interface is user-selectable for up to 18 languages, chosen at first start-up and changeable in the setup menu or MSA Link.

The ALTAIR 5X in plain words

  • Pumped multigas detector: up to six gases, PID or IR CO2 options, integral pump, IP65, 10-foot drop test, UL/CSA/ATEX/IECEx as MSA lists them.
  • Calibration check every day before use: gas through the demand regulator to the pump inlet, readings within the cylinder limits.
  • Calibrate: up button five seconds, confirm ZERO (SENSOR REFRESH, progress bar, PASS), then gas on the inlet and power at SPAN; PASS or FAIL per sensor.
  • A failed span is retried with fresh gas and sound tubing before a sensor is blamed; the heart symbol is the end-of-sensor-life warning.
  • Reactive gases (Cl2, NH3, ClO2) need a special regulator and short PTFE tubing dedicated to that gas.
  • CAL DUE is settable from 1 to 180 days; the GX2 stand defaults to 30 days and bump/cal on fail.
  • Shutdown: hold the power button through the bar. Charge in a safe area only. Bluetooth ended in July 2022.
MSA ALTAIR 5X operating manual (10150945 r02), ALTAIR 5X FAQ, ALTAIR 5X product page, GALAXY GX2 quick start guide. Fetched Nov 10 2026.

Questions people ask

How do I calibrate an MSA ALTAIR 5X?

Hold the up button five seconds in fresh air, confirm ZERO with the power button, then connect the demand regulator and cylinder to the pump inlet and press power at SPAN; the display reads PASS or FAIL per sensor.

How often do you calibrate an MSA ALTAIR 5X?

A calibration check before each day’s use and a full calibration periodically and after any failed check, sensor change or battery change; the CAL DUE reminder runs from 1 to 180 days and the GX2 defaults to 30.

What does the MSA ALTAIR 5X detect?

Up to six gases: combustible (LEL, IR methane or IR CO2), oxygen and XCell toxic sensors for CO, H2S, SO2, NO2, NH3, Cl2, ClO2, HCN and PH3, plus a PID option for VOCs, as MSA lists them.

What is COMB on the ALTAIR 5X?

The combustible-gas channel: the catalytic sensor reading in percent LEL or percent methane, or the IR reading on an IR unit; MSA’s defaults are 0.5 percent CH4 low and 1 percent high.

How do you use the ALTAIR 5X?

Turn it on in fresh air, let the self-test and pump test run, accept any sensor change, do the calibration check, then sample through the line or wear it; the down button pages the readings and the up button clears them.

Where can I find the manual for the ALTAIR 5X?

On MSA’s ALTAIR 5X product page under documents, linked from our product pages; this guide follows operating manual 10150945 r02.

What is the price of the MSA ALTAIR 5X?

Per configuration; each row in the band carries the current price, and the PID version is the highest because of the PID sensor and lamp.

What is the typical life expectancy of the ALTAIR 5X?

MSA prints sensor lives (SO2 four years, NH3 and Cl2 three, O2 more than four) rather than an instrument life; sensors, filters, pump and battery are all replaceable.

How do I turn off the ALTAIR 5X?

Press and hold the power button until the HOLD BUTTON FOR SHUTDOWN bar completes.

Why did my ALTAIR 5X fail calibration?

MSA lists an empty or expired cylinder and bad tubing or fittings before a worn sensor, and says to retry before replacing the sensor; a sensor at end of life shows the blinking heart.

Does the GALAXY GX2 work with the ALTAIR 5X?

Yes, for the calibration check and calibration with a record; MSA notes it cannot test a chlorine dioxide sensor.

Can the ALTAIR 5X read CO2?

With the IR CO2 sensor option, 0 to 10 percent by volume, at 0.5 and 1.5 percent alarms as MSA ships it.

Does the ALTAIR 5X have Bluetooth?

Not on current units: MSA’s product page states Bluetooth has not been available on the 4XR and 5X since July 2022.

Why does chlorine need different tubing on the 5X?

MSA states reactive gases diffuse into rubber and plastic tubes and starve the calibration, so it requires a special regulator and short PTFE tubing dedicated to that gas.

Related guides

Bump test vs calibrationWhat each does and how oftenWhat is calibration gas?And how to choose the right cylinderGas detection for confined space entryWhat to test and the orderHow to calibrate, bump test and reset an MSA ALTAIR 4XRButtons, zero and span, the LEDs and the 4X differencesIs there a detector for high levels of carbon dioxide?Portable CO2 monitors, colorimetric tubes and appsGas detector sensor lifeWhen to replace sensors

The ratings, test results and standards shown here are the manufacturers' published values, reproduced as published. Nothing on this page is a recommendation by Bayshore Safety that any product is suitable for a particular task, hazard or workplace. Selecting safety products and protective equipment is the responsibility of the end user and the employer, based on their own hazard assessment and the regulations that apply to their work. Confirm every value on the manufacturer's own documentation before use.

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