Problems and fixes

Find your symptom. Each page explains what the hardware is actually doing, then gives the checks in order — the ones that cost nothing come first, so nobody buys a filter to solve a wrapper left on the last one.

• The filter light stays on after changing the filter You fitted a brand-new filter and the replacement indicator is still lit, or blinking, exactly as before.
• Your air purifier smells bad The unit gives off a smell — sour, musty, chemical, or like something burning — and it is worse when it runs.
• Weak airflow from your air purifier The unit is running but barely moving air, or noticeably less than it used to.
• You bought a replacement filter that does not fit The filter you ordered does not seat, or it fits but the unit will not close, or it is visibly the wrong shape.
• Can you wash an air purifier filter? You want to get more life out of a filter and are wondering whether it can be rinsed, vacuumed or washed.
• How long do air purifier filters really last? The box says six or twelve months and you want to know whether that applies to you.
• The air quality light stays red (or never changes) The air-quality ring or light sits on red, or stays on one colour and never reacts to anything.
• Your air purifier is too loud The unit is louder than you expected, or louder than it used to be, at the speed you need.
• Your air purifier will not turn on Nothing happens when you press power, or the unit starts and stops immediately.
• Dust is still settling with the purifier running The unit runs constantly and surfaces still need dusting as often as before.

Where a step depends on your exact model — a reset sequence, a part number — the filter guide for that unit has the documented procedure. These pages cover what is common across brands.