Coil dry is a button on Fujitsu floor console remotes that runs a 48-minute drying cycle inside the indoor unit. Condensation builds up on the internal coil during cooling and dry mode operation, and the coil dry function dries this out afterwards to help prevent organic growth and restrain bacteria inside the unit.

The cycle can be started during normal operation or when the unit is stopped. A coil dry icon stays lit on the remote for the full 48 minutes. Pressing the button again resets the timer to the start. Pressing the standard start or stop button cancels the cycle early. Fujitsu recommends running it at the end of the cooling season, or before any extended period without use, to clear stagnant moisture from inside the casing.

Coil dry is a preventive function only. Fujitsu is explicit that it cannot remove organic growth or bacteria that has already developed, and it has no sterilising effect. If your unit already has a musty smell or visible growth inside the coil or fan wheel, coil dry will not resolve it. That's a job for a professional clean of the internal coil and drain pan.

For a full breakdown of how dry mode works and when to use it, see our heat pump dry mode guide.