What the symbols, messages and lights on a CPAP machine mean
84 icons, messages and lights on 6 machines from 4 makers, each from the maker’s own user guide. “High leak”, a crossed-out icon or a flashing button means different things on different machines, so pick your maker, or type the words your screen shows.
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.
Find it by what you see
84 entries.
- ResMed AirSense 10: High leak detected, connect your tubingResMed gives two possible causes: the air tubing may not be connected properly, or the mask may be fitted incorrectly.
- ResMed AirSense 10: High leak detected, check your water tub, tub seal or side coverThe leak is at the humidifier, not the mask: the water tub may not be inserted properly, or the seal inside its lid may not be in place.
- ResMed AirMini: Therapy stops by itself (high leak with SmartStop on)ResMed lists “My therapy has stopped” with two causes: the air tubing may be disconnected, or there may be a high leak while SmartStop is enabled (SmartStop ends therapy when it senses the mask has come off).
- Fisher & Paykel Healthcare SleepStyle: MASK LEAK: HIGHOne of the therapy-data screens under My Data.
- React Health Luna G3: Leak!!An audible alert while air is flowing: the machine has measured an excessive air leak rate and shows “Leak!!” on the screen.
- ResMed AirSense 10: Mask Seal (Sleep Report): “Good mask seal” or “Needs adjusting”After you stop therapy the Sleep Report shows one of two icons for Mask Seal, which the guide labels “Good mask seal” and “Needs adjusting, see Mask Fit”.
- ResMed AirSense 11: Mask Fit (MORE menu)A function that helps you assess and find possible air leaks around the mask.
- ResMed AirMini: Mask Fit (AirMini app)On the AirMini, Mask Fit runs from the AirMini phone app, not the machine.
- Philips Respironics DreamStation 2: Last Session Mask fit: “Good fit” or “Adjust fit”A screen in the summary shown after therapy is turned off.
- React Health Luna G3: Mask Fitting Test: “great” or “need to adjust”An option in the patient menu that tests whether the mask is worn correctly.
- ResMed AirSense 10: Humidity, Humidifier warming, Humidifier coolingThree of the icons the AirSense 10 screen can show.
- ResMed AirSense 10: Still blowing air after you stop therapyThe machine is cooling down: it blows a small amount of air so that water does not condense in the air tubing.
- ResMed AirSense 11: Humidifier warming, Humidifier coolingStatus-bar icons: the water in the humidifier tub is pre-heating, or is cooling.
- Philips Respironics DreamStation 2: Humidification symbolShown on the therapy screen when the adjustable humidifier setting is enabled.
- Fisher & Paykel Healthcare SleepStyle: Humidity drops (0 to 7)The humidity level is drawn as a row of drops: 0 is all drops clear, 7 is all drops shaded.
- React Health Luna G3: Humidifier icon with a numberThe number next to the humidifier icon on the main screen is the humidity level.
- ResMed AirSense 11: Humidifier faultA status-bar icon: the machine has detected a fault in the humidifier.
- ResMed AirSense 10: Humidifier (Sleep Report): might be faultyThe Sleep Report after therapy shows whether the humidifier is working.
- Philips Respironics DreamStation 2: Humidifier ErrorHumidification control is disabled.
- Philips Respironics DreamStation 2: Humidifier OffThe attached battery does not support humidification, so the humidifier is off while you run from the battery pack.
- Fisher & Paykel Healthcare SleepStyle: Error code 400–499Humidity may have been disabled.
- React Health Luna G3: Humidifier Failure!!When the humidifier is fitted, an audible alert sounds when it fails to work, and the screen shows “Humidifier Failure!!”.
- Philips Respironics DreamStation 2: Tube ErrorHeated tube error (only when a heated tube is fitted): the heated tube may be overheated or damaged.
- Fisher & Paykel Healthcare SleepStyle: ThermoSmart iconThe ThermoSmart breathing tube is connected and working correctly.
- Fisher & Paykel Healthcare SleepStyle: ThermoSmart icon with a line through it, or missingThe tube may not be connected correctly, or there may be an error with the ThermoSmart tube.
- Fisher & Paykel Healthcare SleepStyle: Error code 510 or 512There may be a problem with the ThermoSmart breathing tube.
- Fisher & Paykel Healthcare SleepStyle: Error code 500–599 (not 510 or 512)The ThermoSmart tube may have been disabled.
- React Health Luna G3: Heated tubing icon turns into a numberWhen the heated tubing is connected correctly, its icon on the main screen becomes a number: the heat level, one of five.
- ResMed AirSense 10: Ramp Time and Ramp Time Auto icons; the spinning circleRamp Time is the period during which the pressure rises from a low start pressure to your prescribed pressure; with Auto the machine detects when you have fallen asleep and then rises.
- ResMed AirMini: Air feels too weak at the start (ramp in the AirMini app)The AirMini’s ramp is set in the app.
- Philips Respironics DreamStation 2: RAMP PLUS (Ramp+) symbolRAMP PLUS keeps a lower starting pressure for a set time (30 minutes by default) while you fall asleep.
- Fisher & Paykel Healthcare SleepStyle: Ramp symbolAppears when you press and hold Start/Stop for 3 seconds.
- ResMed AirSense 10: Wireless signal strength (green bars)Shown at the top right of the screen: all bars means good coverage, fewer bars means poor coverage.
- ResMed AirSense 10: No wireless connectionNo wireless network is available.
- ResMed AirSense 10: Wireless transfer not enabled (grey)Data transfer is not enabled for your machine.
- ResMed AirSense 11: Cellular signal strength; No cellular connectionThe first shows the strength of the mobile connection; the second means cellular coverage is not available.
- Philips Respironics DreamStation 2: Cell modem signal strengthShows the signal strength of the cellular modem on machines that have one.
- Fisher & Paykel Healthcare SleepStyle: Modem icon; modem icon with a line through itThe modem icon shows the modem is on and working correctly (not available in every country).
- React Health Luna G3: Signal icons: strong, moderate, weak, no signal foundWith the optional Cellular Module fitted, one of four signal icons appears in the status bar.
- ResMed AirSense 10: Airplane Mode iconAirplane Mode is on (it is turned on in My Options).
- ResMed AirSense 11: Airplane modeThe machine is in airplane mode.
- ResMed AirMini: Bluetooth light constantly whiteAirplane mode: Bluetooth on the machine is disabled.
- Philips Respironics DreamStation 2: Airplane mode symbolAirplane Mode is on.
- ResMed AirSense 11: Bluetooth connectedThe machine is connected to your phone (the myAir app) by Bluetooth.
- ResMed AirMini: Bluetooth light: flashing blue, steady blue, offFlashing blue: the machine is discoverable and ready to pair.
- Philips Respironics DreamStation 2: Bluetooth symbol, grey or whiteGrey: Bluetooth is available.
- Fisher & Paykel Healthcare SleepStyle: Bluetooth icon; with a line through itThe icon shows Bluetooth is on and working.
- ResMed AirSense 10: SD card error, remove your card and press Start to begin therapyThe SD card may not be inserted correctly.
- ResMed AirSense 10: Read only card, please remove, unlock and re-insert SD cardThe small switch on the side of the SD card may be in the lock (read-only) position.
- ResMed AirSense 10: SD light flashingData is being written to the card.
- ResMed AirSense 11: Blue light at the SD card coverThe indicator by the SD card cover is blue when data is being written to the SD card.
- Philips Respironics DreamStation 2: SD Error, Remove/ReinsertThe machine cannot read the SD card: the card may have a problem, it may have been removed while being written to, or it may have been inserted incorrectly.
- Philips Respironics DreamStation 2: SD Full, Contact providerThe SD card is full.
- Philips Respironics DreamStation 2: SD Removed, ReinsertThe SD card was removed and not put back before this therapy session started.
- Philips Respironics DreamStation 2: SD Card Activity, Do not removeA status message: the SD card is being read or written.
- React Health Luna G3: SD Card Full! / Reinsert SD Card!“SD Card Full!” shows when the SD card has reached its maximum capacity.
- Fisher & Paykel Healthcare SleepStyle: InfoUSB icon; with a line through it, or missingThe SleepStyle records to an F&P InfoUSB stick instead of an SD card.
- ResMed AirSense 11: System fault, refer to user guide, Error 4ResMed gives three possible causes: the machine may have been left somewhere hot; the air filter may be blocked; there may be water in the air tubing.
- ResMed AirSense 11: Any other “System fault, refer to user guide Error X”An unrecoverable error has occurred on the machine.
- ResMed AirSense 10: System fault, refer to user guide, Error 0XX (and all other error messages)An unrecoverable error has occurred on the machine.
- Philips Respironics DreamStation 2: Service Required, Contact support (light blinks continuously)A device error has put the machine into a “Safe State”: the power stays on but the airflow is disabled.
- Fisher & Paykel Healthcare SleepStyle: Error code 100–199The machine may not be able to provide effective therapy: it may have shut down, or may not be able to provide your prescribed pressure.
- React Health Luna G3: Device Fault!!!An audible alert: no airflow is coming out of the machine.
- ResMed AirSense 11: Start Therapy/Standby light: green, white, flashing whiteGreen: standby.
- ResMed AirMini: Light above Start/Stop: green, or flashing greenThe green light above the Start/Stop button shows the machine has power (the power supply unit has its own green light too).
- Philips Respironics DreamStation 2: Therapy button ring: blue or whiteBlue: therapy is on (the ring goes dark when therapy is on and the screen has gone dark).
- Philips Respironics DreamStation 2: Check Power (light blinks continuously)An incompatible (incorrect) power supply is attached.
- Philips Respironics DreamStation 2: Low Voltage (light blinks continuously)Low voltage: an incompatible power supply is attached.
- React Health Luna G3: Power Failure!!!An audible alert that sounds 6 seconds after the machine loses power while it is delivering air.
- React Health Luna G3: Low Input Voltage!!The voltage from the power adaptor is lower than 22 V; an audible alert sounds.
- ResMed AirSense 10: Screen is blackEither the screen backlight has turned itself off (it does so after a short time), or the power is not connected.
- Fisher & Paykel Healthcare SleepStyle: Therapy won’t start and the screen is blankThe power cord may not be connected correctly, or there may have been a storm, power cut or power surge.
- ResMed AirSense 10: Tubing blocked, check your tubingThe air tubing may be blocked.
- Philips Respironics DreamStation 2: Blocked inletBlocked airway: something is blocking the air inlet on the machine.
- Philips Respironics DreamStation 2: Low leakBlocked airway: a blockage at the tube or the mask.
- React Health Luna G3: Air from the machine is unusually hotThe air inlet may be partly blocked, so too little air is getting into the machine.
- Philips Respironics DreamStation 2: Prescription UpdatedA status message: your prescription has been updated.
- Philips Respironics DreamStation 2: Prescription InvalidA prescription or setting update was unsuccessful.
- Philips Respironics DreamStation 2: Device Update, Hold to Confirm, Click to CancelA new software version is available for the machine.
- ResMed AirSense 11: Prescription settings have not been appliedIf the machine was sent straight to your home, the prescription settings may not be on it yet: they arrive over the wireless connection.
- ResMed AirSense 10: Screen and buttons flashingA software upgrade is in progress.
- React Health Luna G3: Please Change Filter!With the filter reminder turned on, an audible alert sounds and this message shows once the preset replacement time is reached and the air filter has not been replaced.
- React Health Luna G3: Please Replace Tubing!The same for the tubing: the preset replacement time has been reached and the tubing has not been replaced.
- React Health Luna G3: Please Replace Mask!The same for the mask.
Nothing matches all of those. Try fewer words, or “Anything” and “Any maker”: makers word the same thing differently (“Leak!!” on one is “High leak detected” on another).
By what it is about
- High leakResMed, Fisher & Paykel Healthcare and React Health
- Mask fit resultResMed, Philips Respironics and React Health
- Humidifier and humidity iconsResMed, Philips Respironics, Fisher & Paykel Healthcare and React Health
- Humidifier faultResMed, Philips Respironics, Fisher & Paykel Healthcare and React Health
- Heated tubePhilips Respironics, Fisher & Paykel Healthcare and React Health
- RampResMed, Philips Respironics and Fisher & Paykel Healthcare
- Wireless or cellular signalResMed, Philips Respironics, Fisher & Paykel Healthcare and React Health
- Airplane modeResMed and Philips Respironics
- BluetoothResMed, Philips Respironics and Fisher & Paykel Healthcare
- SD card and data cardResMed, Philips Respironics, React Health and Fisher & Paykel Healthcare
- System fault and error codesResMed, Philips Respironics, Fisher & Paykel Healthcare and React Health
- Light on the start buttonResMed and Philips Respironics
- Power and voltage alertsPhilips Respironics, React Health, ResMed and Fisher & Paykel Healthcare
- Tubing or air inlet blockedResMed, Philips Respironics and React Health
- Prescription or settings updatePhilips Respironics and ResMed
- Replace filter, tubing or mask remindersReact Health
By maker
The marks printed on the machine’s label
The marks printed on the machine’s label and box are the standard medical and electrical symbols, and each already has its own page here. As the ResMed AirSense 10 guide words them:
Source: AirSense 10 user guide (AirSense 10 AutoSet, AutoSet for Her, Elite and CPAP, with HumidAir) (378947/1, 2021-02), Symbols section, checked 2026-09-29.
What these pages cannot do
- They cannot tell you what your pressure, humidity or ramp should be. Those are set for you; ask your equipment provider or clinician.
- They cannot see your machine. The same words can mean different things on two models from one maker, so match the model name first.
- They carry only what each maker’s user guide states. An icon or message the guide does not explain is not here, and where a guide gives no step, the page says so rather than inventing one.
Left out, and why
A maker gets a page when its own user guide documents at least 5 icons, messages or lights and we could read it. These were not used, or only in part:
- Bilevel machines (Philips DreamStation BiPAP, ResMed AirCurve, Luna G3 BPAP) — Bilevel machines have their own screens, alarms and manuals; these pages cover CPAP and auto-CPAP machines only. www.documents.philips.com Checked 2026-09-29.
- Philips DreamStation (first generation) and DreamStation Go — We read the DreamStation 2 manual for this pass; the first-generation DreamStation and the Go travel machine have different screens and are not covered, so do not match their messages against the DreamStation 2 page. www.philips.com Checked 2026-09-29.
- F&P SleepStyle Quick Reference Guide — The file is served, but our text reader could not get any text out of it, so nothing on these pages comes from it. The full Use and Care Guide is used instead. resources.fphcare.com Checked 2026-09-29.
- F&P SleepStyle Use and Care Guide, US edition — Its troubleshooting and error-code tables did not come out as readable text, so we used the edition F&P links from its Canadian SleepStyle page, which reads cleanly and covers the same two models. resources.fphcare.com Checked 2026-09-29.
Sources
Each maker’s own user guides only, read on the date shown.
ResMed
- ResMed: AirSense 10 user guide (AirSense 10 AutoSet, AutoSet for Her, Elite and CPAP, with HumidAir) — 378947/1, 2021-02. document.resmed.com Checked 2026-09-29.
- ResMed: AirSense 11 user guide (Americas) — 398133/2, 2021-10. document.resmed.com Checked 2026-09-29.
- ResMed: AirMini user guide — 388135/1, 2020-03. document.resmed.com Checked 2026-09-29.
Philips Respironics
- Philips Respironics: DreamStation 2 Auto CPAP / CPAP user manual — 1143534 R02, 06/11/2021. www.documents.philips.com Checked 2026-09-29.
Fisher & Paykel Healthcare
- Fisher & Paykel Healthcare: F&P SleepStyle Use and Care Guide (SleepStyle Auto, SleepStyle CPAP) — Use and Care Guide, English section A. resources.fphcare.com Checked 2026-09-29.
React Health
- React Health: Luna G3 APAP / Luna G3 CPAP User Manual — V1.7, issue date February 29, 2024. www.reacthealth.com Checked 2026-09-29.