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What This Guide Helps With
Troubleshooting low oxygen purity alarms caused by airflow restriction, filter issues, cannula problems, environmental conditions, or internal concentrator failure.
Step-by-Step Troubleshooting
Ensure Patient Safety First
Confirm whether the oxygen concentrator is actively supporting a patient.
If the patient requires continuous oxygen therapy, have clinical staff move the patient to another verified oxygen source before troubleshooting.
Expected outcome: The patient is not dependent on a concentrator with questionable oxygen output.
If patient safety is restored, continue troubleshooting only in a safe area.
Confirm the Reported Alarm
Power the Invacare Perfecto2 on and allow it to run long enough to confirm the reported low oxygen purity alarm.
Observe the alarm behavior, indicator lights, audible alarm, and whether the alarm occurs immediately or after warm-up.
Expected outcome: The issue is confirmed before unnecessary parts replacement or repair escalation.
Check the Oxygen Flow Setting
Verify the flowmeter is set within the prescribed and manufacturer-supported operating range.
Confirm the flow ball is stable and not set above the device’s rated output.
Expected outcome: Excessive flow demand is ruled out as a cause of low oxygen concentration.
If reducing the flow to an approved range clears the alarm and oxygen purity stabilizes, document the finding and stop.
Inspect the Cannula, Tubing, and Humidifier Bottle
Check for kinked tubing, crushed cannula lines, blocked nasal cannula tips, excessive tubing length, or a clogged humidifier bottle.
If a humidifier bottle is installed, verify it is not overfilled, cracked, cross-threaded, or creating back pressure.
Expected outcome: External patient accessory restrictions are corrected.
If replacing the tubing, cannula, or humidifier bottle resolves the alarm, return the unit only after performance is verified.
Check the Outlet Port and Oxygen Connection
Inspect the oxygen outlet fitting for obstruction, damage, looseness, or residue.
Confirm the tubing is fully seated and not leaking at the outlet connection.
Expected outcome: Oxygen flow is leaving the concentrator without obvious restriction or leakage.
Inspect the External Cabinet Filter
Check the external cabinet filter for dust, lint, pet hair, blockage, or moisture.
Clean or replace the filter according to facility procedure.
Expected outcome: Adequate room air intake is restored.
If the alarm clears after filter service and oxygen output verifies within acceptable limits, document the correction and stop.
Check the Room Environment
Verify the concentrator has adequate clearance around the cabinet and is not placed against a wall, curtain, bed linen, or furniture.
Confirm the unit is not operating in an excessively hot, dusty, or poorly ventilated area.
Expected outcome: The concentrator has enough airflow for cooling and sieve bed operation.
Why it matters: Restricted intake or poor cooling can reduce concentrator performance and trigger purity alarms.
Listen for Abnormal Compressor Operation
With the device running, listen for unusual compressor sounds, weak operation, loud rattling, rapid cycling, or air leaks.
Do not open the unit for internal diagnosis during basic troubleshooting.
Expected outcome: Obvious signs of internal compressor, valve, or pneumatic failure are identified for repair escalation.
Check for Obvious External Damage
Inspect the cabinet, power cord, caster area, outlet fitting, and filter cover for damage from impact, transport, liquid exposure, or contamination.
Expected outcome: Physical damage is identified before the unit is returned to service.
If damage is found, remove the concentrator from service.
Verify Output With Appropriate Test Equipment
In a Biomed-controlled setting, connect an oxygen analyzer and verify oxygen concentration after the unit has warmed up.
Confirm the analyzer is calibrated or verified before relying on the reading.
Expected outcome: The low oxygen purity complaint is either confirmed or ruled out using an independent measurement.
If oxygen concentration remains low after external checks, stop troubleshooting and escalate for repair.
If the Problem Persists
If the low oxygen purity alarm continues after checking flow setting, tubing, humidifier bottle, filters, airflow clearance, outlet connection, and oxygen output verification, common external causes have been ruled out.
The issue is likely internal, such as compressor weakness, sieve bed degradation, valve failure, internal leak, sensor issue, or control problem.
The device should be:
- Removed from service
- Labeled Out of Service
- Sent for repair or bench evaluation
Knowing when to stop is proper troubleshooting. A concentrator that cannot reliably produce acceptable oxygen concentration should not remain available for patient use.
Clinical Use Tip
Do not troubleshoot a low oxygen purity alarm while the patient is relying on that concentrator. Move the patient to another verified oxygen source first, then evaluate the device in a safe, non-patient-use setting.
Work Order Documentation (CCR Method)
CCR = Complaint, Cause, Resolution
Complaint
What was reported by the clinical staff.
Example:
"Clinical staff reported the Invacare Perfecto2 was alarming for low oxygen purity during patient oxygen setup."
Cause
What was observed during troubleshooting.
Example:
"External inspection found a heavily clogged cabinet filter and restricted airflow around the concentrator."
Resolution
What action was taken.
Example:
"Cleaned/replaced the cabinet filter, restored proper clearance, verified stable flow and acceptable oxygen concentration, and returned the unit to service."
Helpful Details to Include (If Known)
- Whether the alarm occurred immediately or after warm-up
- Flowmeter setting at time of complaint
- Oxygen analyzer reading after warm-up
- Cabinet filter condition
- Tubing, cannula, and humidifier bottle condition
- Any kinks, leaks, or blocked accessories found
- Alarm light and audible alarm behavior
- Unusual compressor noise
- Signs of heat, dust, odor, or cabinet damage
- Final device status: returned to service or removed for repair
Final Thought
Low oxygen purity alarms should be handled with patient safety first and a logical troubleshooting path. Rule out external airflow restrictions, accessory problems, excessive flow demand, and environmental causes before suspecting internal failure. If oxygen concentration cannot be verified as acceptable, remove the unit from service and document the complaint, cause, and resolution clearly.
That is successful troubleshooting.