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The light on a CPAP machine’s start button

The light in or above the start button is the one thing you can see in the dark. Steady colours mean standby or therapy; on these machines a flashing light goes with an error.

Therapy settings: This page explains what a CPAP machine’s screen or light is telling you, in the maker’s words. It is not medical advice: ask your equipment provider or clinician about your therapy settings, and do not change your pressure or any prescribed setting because of anything here.

ResMed

  1. ResMed AirSense 11 A light on the machine

    Start Therapy/Standby light: green, white, flashing white

    Green: standby. White: therapy, Test Drive or Mask Fit is running. Flashing white: a system error has occurred.

    What ResMed says to do

    1. If it flashes white, look up the message on the screen in the troubleshooting table (see System fault and error codes).

    Source: AirSense 11 user guide (Americas) (ResMed, 398133/2, 2021-10), checked 2026-09-29.

  2. ResMed AirMini A light on the machine

    Light above Start/Stop: green, or flashing green

    The green light above the Start/Stop button shows the machine has power (the power supply unit has its own green light too). Flashing green means an error has occurred on the machine.

    What ResMed says to do

    1. If it flashes green, unplug the machine, wait a few seconds and plug it back in.
    2. If the problem persists, contact your care provider. Do not open the machine.
    3. If you cannot start therapy and there is no green light, connect the power supply and make sure the plug is fully inserted.

    Source: AirMini user guide (ResMed, 388135/1, 2020-03), checked 2026-09-29.

Everything else ResMed’s machines show: ResMed CPAP icons and messages.

Philips Respironics

  1. Philips Respironics DreamStation 2 A light on the machine

    Therapy button ring: blue or white

    Blue: therapy is on (the ring goes dark when therapy is on and the screen has gone dark). White: the machine is plugged in and therapy is off.

    No action is needed. A ring that blinks continuously comes with a message: see Service Required, Check Power or Low Voltage.

    Source: DreamStation 2 Auto CPAP / CPAP user manual (Philips Respironics, 1143534 R02, 06/11/2021), checked 2026-09-29.

Everything else Philips Respironics’s machines show: Philips Respironics CPAP icons and messages.

Other things a CPAP machine shows

Sources

Each maker’s own user guide only, read on the date shown. Nothing here comes from third-party CPAP forums or “error code” sites.

Find any icon, message or light on your machine →