Portable Oxygen Concentrator Stopped Working? Troubleshooting Guide
Most POC problems have a simple first step. Here's how to work through them quickly, and when to hand it off to a technician.
Chief Sales Officer, Main Clinic Supply
14+ years helping patients transition from tanks to portable concentrators
Version 1.0 | Published May 2, 2026 | Last verified: May 2, 2026 | Next review: May 16, 2026
Most of what goes wrong with a portable oxygen concentrator falls into a small number of categories: power supply, cannula and tubing, airflow and ventilation, and internal component wear. The majority of alarms you will hear during normal ownership are not serious. But one of them, the low purity alarm, requires you to stop using the unit and get it serviced before you rely on it again. Knowing the difference between an alarm you can fix yourself in 60 seconds and one that needs a technician is the whole point of this guide.
Fast Facts: POC Troubleshooting
- Most alarms are not emergencies: Low battery, no-breath detection, and high temperature alarms usually have a simple fix.
- Low purity alarm is the exception: Stop using the unit and call your supplier the same day.
- Check the basics first: Power source, battery seating, filter condition, and cannula connection resolve most common issues.
- MCS services Inogen in-house: Other major brands are serviced through manufacturer programs coordinated by our team.
- Ask about a loaner: If your concentrator is your primary oxygen source, ask your supplier about a loaner unit during repair.
First Steps When Something Goes Wrong
Before doing anything else, ask yourself one question: am I getting adequate oxygen right now? If the answer is no, or if you're not sure, switch to a backup oxygen source or call for help. Do not spend time troubleshooting when you are symptomatic.
If the device is alarming but you are comfortable, work through this sequence before assuming the worst.
- Check the power source. Is the battery seated correctly? If you're on AC power, is the adapter plugged securely into both the wall and the device? Is the outlet live? (Try a lamp.)
- Check the cannula and tubing. Is the cannula seated in both nostrils? Is the tubing kinked anywhere between the device and your nose? Is the nasal cannula prong blocked or visibly soiled?
- Check the air filter. A clogged particle filter is one of the most common causes of alarms. Remove it, inspect it, and reinstall it if clean or replace it if dirty.
- Check the environment. Is the unit in a confined space with vents blocked? Is the ambient temperature unusually high? Move the unit to a well-ventilated, cooler spot and let it run for a few minutes.
- Turn the unit off, wait 30 seconds, and turn it back on. A restart clears transient errors on most devices.
If the alarm clears after any of these steps, you've found the cause. If the alarm persists or a different alarm appears, consult the alarm reference below.
Alarm Reference Guide
Alarm systems vary by manufacturer and model, but the categories are consistent across most modern portable concentrators. Here are the common ones and what they mean.
| Alarm Type | What It Means | What to Do | Urgency |
|---|---|---|---|
| Low battery | Battery charge is below a safe operating threshold | Plug into AC power or swap to a charged battery | Low |
| No breath detected | The unit has not detected an inhalation within the expected window | Check cannula position and tubing; breathe through nose | Low to medium |
| High temperature | Internal temperature has exceeded a safe limit | Move to a cooler, ventilated location; check filter; allow to cool | Medium |
| Low oxygen purity | Oxygen output has dropped below the therapeutic range | Stop use. Switch to backup source. Call supplier same day. | High |
| Device fault / error code | An internal system error the device cannot self-resolve | Note the error code; try restart; call supplier if it recurs | Medium to high |
| AC power disconnected | Unit has switched from wall power to battery (or lost AC) | Verify plug connections; check outlet; confirm intended | Low |
Power and Battery Problems
Power problems account for a large share of the calls our service team handles. They're also the easiest to resolve.
The unit won't turn on
Start with the battery. Remove it, inspect the contacts for corrosion or debris, reseat it firmly, and try again. If you have a second battery, swap to it. If neither works and you're on AC, try a different outlet and confirm the DC adapter cable is fully seated at both ends. If none of this resolves it, the issue is likely the power management circuit or the adapter itself, and the unit needs service.
Battery drains faster than it used to
Lithium battery capacity decreases with charge cycles over time. A battery that is one to two years old and used daily may retain 70 to 80 percent of its original capacity. This is normal. When runtime drops enough to affect your daily routine, it's time to replace the battery rather than the device. Battery replacement is typically $250 to $500 depending on the model and battery size.
Unit turns off unexpectedly while on AC power
Unexpected shutdowns on AC usually point to one of three things: a faulty AC adapter, an overheating event triggering a protective shutdown, or an internal fault. Check that the adapter is the correct wattage for your model (some generic adapters do not supply enough current), ensure ventilation is unobstructed, and note whether the unit feels hot to the touch. If the shutdown happens consistently, call for service.
Breath Detection Alarms
Pulse dose concentrators rely on a flow sensor to detect the start of each inhalation and release an oxygen bolus at the right moment. When the sensor doesn't detect a breath within its expected window, the device alarms. This alarm is more annoying than it is dangerous in most cases, but it can indicate a real problem if it persists under normal breathing conditions.
The most common causes:
- Cannula displacement. The prongs have slipped out of one or both nostrils. This happens more often than users expect, especially during sleep attempts, head movement, or activity.
- Tubing kink. A kink in the oxygen tubing between the device and the cannula can block flow sensing. Straighten the tubing and ensure there are no sharp bends.
- Mouth breathing. If you are breathing primarily through your mouth, the nasal sensor will not detect inhalation. Pulse dose devices require nasal breathing to function reliably.
- Very shallow breathing. At rest or during certain exertion patterns, breathing can become shallow enough that the sensor misses the breath. Some units have adjustable sensitivity settings. Check your manual.
- Dirty or damaged sensor port. The inlet port where the cannula connects can accumulate moisture or debris over time. A gentle cleaning with a dry cloth and a restart often resolves this.
If the breath detection alarm triggers consistently under normal nasal breathing conditions, the sensor or circuit needs professional calibration or replacement.
Low Purity: The Alarm That Requires Service
This is the one alarm that changes what you should do next. A low purity alarm means your concentrator has detected that the oxygen it is producing has fallen below the therapeutic range, typically below 82 to 87 percent purity depending on the unit's internal threshold. You may not notice any immediate difference in how you feel, because oxygen at lower concentrations is still better than room air (which is roughly 21 percent oxygen). But you are not receiving the therapeutic dose your physician prescribed.
The most common causes of low purity alarms are degraded sieve beds (the zeolite columns that filter nitrogen from room air), a severely blocked air filter that has reduced airflow, or an internal compressor issue. Sieve bed replacement is the most common repair. On units where the sieve beds are a replaceable component, this is a routine service item. On units where the sieve beds are integrated, service costs vary by model.
For context on sieve bed lifespan and what to expect at different usage levels, see our guide to how long portable oxygen concentrators last and our overview of all-day POC safety.
When to Call a Technician Instead of Troubleshooting Further
Self-troubleshooting covers a real range of issues. But some problems are not self-fixable, and continuing to troubleshoot wastes time you could spend getting the unit repaired. Call your equipment supplier when:
- A low purity alarm has triggered, for any reason.
- The unit emits a grinding sound, a repeated clicking that doesn't resolve on startup, or a rattling that wasn't present before.
- The unit shuts down repeatedly under normal operating conditions.
- An error code appears that is not in the user manual or that recurs after a restart.
- The unit feels significantly hotter than usual on the exterior, even in a well-ventilated environment.
- Battery runtime has declined significantly despite using a battery that is less than one year old.
- You have done everything in the first-steps checklist and the original alarm has not cleared.
If your concentrator is your primary oxygen source, ask about a loaner unit at the start of the service conversation. For a unit going in for anything other than a same-day fix, having backup oxygen arranged matters.
Service Options: Warranty, Out of Warranty, and Service Plans
Under warranty
If your unit is within the manufacturer warranty period, the repair process starts with your equipment supplier. Document the alarm or issue, the date it occurred, and any steps you have already taken. Most manufacturers require service through an authorized service center. Shipping a unit in for warranty repair typically takes one to two weeks depending on the issue and part availability.
Out of warranty
Out-of-warranty repairs are covered by the equipment owner. For a portable oxygen concentrator, common repair costs run from around $150 for a sensor cleaning and calibration to $400 to $800 for sieve bed replacement, to over $1,000 for major compressor work on certain models. The decision of whether to repair or replace depends on the age of the unit, its overall operating hours, and the cost of the specific repair relative to the cost of a replacement.
Service plans
A service plan is an ongoing protection agreement that extends coverage and predictability beyond the manufacturer warranty. For daily users who depend on a concentrator as their primary oxygen source, a service plan answers a real question: what happens when something goes wrong at year four?
What a well-structured service plan typically covers: annual output testing, cleaning, and filter replacement; discounted or covered repairs on covered components; priority turnaround on service requests; and in some cases, access to a loaner unit during extended repairs. Ask about service plan options when you purchase your unit, or at any point during ownership. The cost is usually modest relative to a single out-of-warranty repair.
To compare what you get with a POC versus an oxygen tank setup in terms of reliability and backup options, see our guide to portable oxygen concentrators vs oxygen tanks.
Need Service or Have a Question About Your Unit?
Main Clinic Supply services Inogen portable and stationary concentrators in-house and coordinates manufacturer service for all other major brands. Our certified technicians answer the phone during business hours. We also offer output testing and annual maintenance for units purchased anywhere.
Call 1-800-775-0942 to speak with a certified oxygen specialist about your service needs, or visit our portable oxygen concentrator collection to explore current options if replacement is the right call.
Main Clinic Supply ships and provides service coordination throughout the United States and Canada.
Frequently Asked Questions
What should I do if my portable oxygen concentrator stops working?
First, switch to a backup oxygen source if you have one, or call 911 if you are experiencing a medical emergency. Then check the basics in order: confirm the battery is charged and seated properly, check that the AC adapter is connected if you are on wall power, verify that the air filter is not blocked, and move the unit to a cooler location if it feels warm. If none of these steps resolve the problem, contact your equipment supplier for same-day service guidance.
Why is my portable oxygen concentrator alarming?
The most common POC alarms are: low battery (battery needs charging or replacement), no breath detected (the cannula may be loose or you are breathing through your mouth), low oxygen purity (the sieve beds may need service), high temperature (ventilation is blocked or the environment is too hot), and device fault (an internal error that requires service). Consult your device manual for the exact alarm code. A low purity alarm requires professional service before continued use.
What does a low purity alarm mean on a portable oxygen concentrator?
A low purity alarm means the concentrator's internal sensor has detected that oxygen output has dropped below the acceptable therapeutic range. This usually indicates sieve bed degradation, a blocked filter, or an internal component issue. Do not continue relying on the unit for oxygen therapy after this alarm triggers. Contact your equipment provider for service before the next use.
Why does my POC keep alarming that it can't detect my breath?
Breath detection alarms on pulse dose concentrators most often occur because the nasal cannula is not seated properly in the nostrils, the tubing is kinked, the patient is breathing primarily through the mouth, or the breath sensor needs cleaning or calibration. Try reinserting the cannula, straightening the tubing, and ensuring you are breathing through your nose. If the alarm persists under normal nasal breathing, the unit needs service.
Can a portable oxygen concentrator be repaired?
Yes. Most portable oxygen concentrator issues, including sieve bed replacement, compressor service, battery connector repair, and sensor cleaning, can be repaired by a certified technician. Main Clinic Supply performs in-house repairs on Inogen units at its Rochester, Minnesota service facility. Other major brands are serviced through manufacturer programs coordinated by MCS.
How long does it take to get a portable oxygen concentrator repaired?
Turnaround time depends on the issue, the brand, and part availability. Minor repairs and cleaning can often be completed within a few days. Major repairs requiring parts from the manufacturer can take one to two weeks. Ask your supplier about loaner units during the repair period, especially if the concentrator is your primary oxygen source.
Does my warranty cover repairs?
Most manufacturer warranties cover defects in materials and workmanship for a defined period, typically two to five years on the device and one to two years on batteries and accessories. Warranties generally do not cover damage from dropping the unit, liquid exposure, or using the device outside its rated operating parameters. Review your warranty documentation or call your supplier to confirm coverage before authorizing a paid repair.
What is a portable oxygen concentrator service plan?
A service plan is an ongoing protection agreement that covers repair costs, annual output testing, filter replacement, and sometimes loaner units beyond the manufacturer warranty period. Service plans are particularly valuable for daily users who depend on the concentrator as their primary oxygen source, since out-of-warranty repair costs on a portable concentrator can range from a few hundred dollars to over a thousand for major component work.
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Disclaimer: This guide is provided for educational purposes and does not constitute medical advice. Portable oxygen concentrators are Class II medical devices that require a prescription. If you are experiencing respiratory distress, call 911. Always consult with your prescribing physician or equipment supplier before making changes to your oxygen therapy equipment or settings. Repair costs and turnaround times are estimates and vary by model, issue, and supplier.