Purify / Ioniser
Switches on an air-cleaning device inside the indoor unit — an ioniser or a plasma discharge — alongside the filters.
What pressing it does
Press to turn it on and again to turn it off; a lamp or icon shows it is running. Mitsubishi Electric and Daikin both warn that a hissing or fizzing sound from the plasma is normal.
What it does not do
It does not replace cleaning the air filters, and what it removes is each maker’s own claim for its own device — Mitsubishi Electric names airborne fungi, viruses, mold and allergens, Daikin bad odours and viruses — not something this page can verify.
Makes differ, check your unit’s manual: the same drawing can mean different things on different brands, and only your model’s manual says exactly what a button does and which modes it works in.
- What it looks like
- Small plus and minus signs or dots drifting out of a circle, a leaf for “fresh”, or the word ION or PURIFY.
- Names makers use
- ION / Ionizer (Airwell); Ioniser / FRESH (Midea); PURIFIER (Mitsubishi Electric); FLASH STREAMER (Daikin)
Where makers differ
The technology behind the same button differs: an ioniser (Airwell, Midea), a plasma device (Mitsubishi Electric), a streamer discharge (Daikin).
Other symbols with the same shapes
Sources
No single published standard defines air-conditioner remote icons, so this meaning is taken from 4 makers’ own manuals, each fetched and read on the date shown:
- Airwell: Airwell — RC08W remote control manual (PDF) — ION/CLEAN button: short press starts the ionizer; display icon “Display in ionizer & E.S.F mode operation” (E.S.F works together with the ionizer). Checked 2026-09-26.
- Mitsubishi Electric: Mitsubishi Electric — MSZ-LN indoor unit service manual OBH766 revised edition B (PDF, UK library) — 9-12 AIR PURIFYING: “the indoor unit built-in device reduces airborne fungi, viruses, mold, and allergens … A ‘hissing’ sound may be heard … when plasma is being discharged.” Checked 2026-09-26.
- Daikin: Daikin web operation manual — FLASH STREAMER AIR CLEANING operation — “The streamer, a type of plasma discharge … reducing bad odours and viruses. Together with the deodorizing filter … and the air filters, this function cleans the air in the room … may generate a fizzing sound.” Checked 2026-09-26.
- Midea: Midea — Remote controller owner’s manual, RG51A(2)/E and RG51B(2)/E (PDF) — Quick start shows an Ioniser button; remote screen: leaf icon “Displayed when FRESH feature is activated (some units).” Checked 2026-09-26.
Written in our own words; quotations are the makers’ wording.