Adflo low airflow alarm: what it means and what you can check

Ownership information, not safety advice. Does not replace training or a workplace RPE assessment.

Symptom

The audible alarm sounds and all three LEDs on the power switch light up while you're wearing the Adflo PAPR.

What it means

Per 3M's own troubleshooting table, this is the "Low air flow alarm (audible and all three LEDs on power button are lit)" fault. The Specifications section explains the trigger: the alarm activates when airflow falls below 6 CFM (170 lpm) for more than 15–30 seconds, and the unit shuts down 2 minutes after continuous alarm activation. Before that point, the motor automatically speeds up to try to compensate for reduced airflow — the alarm means it could no longer compensate enough.

Steps you can do yourself

1. 01

   Leave the contaminated area

   Exit the work area as soon as the low-airflow alarm activates — don't try to finish the task on reduced airflow, and don't attempt any physical check while you're still in the contaminated area.

   The manual is explicit: "Leave the contaminated area immediately if any of the following conditions occur: ... The low airflow or low battery alarms trigger." (p.17)

2. 02

   Check the breathing tube for blockage

   Examine the full length of the breathing tube and clear any obstruction or blockage you find.

   3M's troubleshooting table lists "Breathing tube is blocked" as the first probable cause for this alarm, with "Check & remove blockage or obstruction" as the corrective action.

   Parts: 834009 — 3M Adflo Breathing Tube with Silencer and QRS Connection (EMEA), 834016 — 3M Adflo Breathing Tube, Self-Adjusting QRS (EMEA), 834017 — 3M Adflo Breathing Tube, Heavy-Duty Rubber QRS (EMEA), 834019 — 3M Adflo Breathing Tube, Long QRS (EMEA)

3. 03

   Check and replace the filter stack if loaded

   Inspect the particle filter and prefilter for blockage or heavy particle loading and replace both if loaded; examine the spark arrestor for damage or heavy soiling and clean or replace it as needed.

   The manual's remaining probable causes for this alarm are "Filter is blocked" and "Filter is fully loaded with particles," with the corrective action "Change HE filter and pre-filter. If using a chemical cartridge, check that the scrim fabric behind the inlet holes is clean and white. Any sign of particle loading on the chemical cartridge indicates improper installation or damaged particle filter assembly." The particle-filter loading indicator (a five-step scale — three green, two red LEDs) is 3M's own way to catch this before the alarm sounds: when a red segment lights, replacement is recommended.

   Parts: 837012 — 3M Adflo Particle Filter P SL (EMEA), 836010 — 3M Adflo Prefilter (pkg of 5, EMEA), 836000 — 3M Adflo Spark Arrestor (EMEA)

4. 04

   Consider whether you're working above the recommended altitude limit

   If you routinely work at altitude, treat this as a known cause on 3M's own troubleshooting table rather than something to physically inspect or repair.

   3M's troubleshooting table lists a fourth probable cause for this alarm: "PAPR is being used above recommended altitude limitation," with the solution "Consider using an alternative 3M PAPR." That's 3M's own stated solution for that specific cause in its manual, not a product recommendation from this site — if altitude is a factor at your site, raise it with your supplier or safety adviser.

5. 05

   Re-run the airflow check before re-entering the area

   After clearing the blockage or replacing the filter stack, run the manual's airflow-check procedure again with the airflow indicator and confirm the floating ball rests at or above the minimum flow mark before you go back into the contaminated area.

   This is the same check-before-use procedure in our pre-use checklist — see /check/adflo-pre-use/. If the ball still won't reach the minimum mark, the manual says to consult the troubleshooting guide rather than proceed.

   Parts: 838020 — 3M Adflo Airflow Indicator (EMEA)

Never do this

When to stop

Sources

Updated 2026-07-13

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