React Health CPAP machine icons, messages and lights
React Health (formerly 3B Medical) sells the Luna G3 CPAP and Luna G3 APAP, made for it by BMC Medical. It has a knob and a colour screen; its alerts sound a tone and show a short message ending in one or more exclamation marks.
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.
React Health Luna G3
14 entries from Luna G3 APAP / Luna G3 CPAP User Manual (V1.7, issue date February 29, 2024), checked 2026-09-29.
React Health Luna G3 Words on the screen
Leak!!
An audible alert while air is flowing: the machine has measured an excessive air leak rate and shows “Leak!!” on the screen.
React Health’s alert table describes this alert but gives no step for it. Its troubleshooting table links leaks to a mask of the wrong size or model, or one not positioned correctly, and says to contact your home care provider for an appropriate mask.
More on this, and what other makers’ machines show: High leak.
Source: Luna G3 APAP / Luna G3 CPAP User Manual (React Health, V1.7, issue date February 29, 2024), checked 2026-09-29.
React Health Luna G3 An icon on the screen
Mask Fitting Test: “great” or “need to adjust”
An option in the patient menu that tests whether the mask is worn correctly. The screen shows the “great” icon if it passes, otherwise the “need to adjust” icon.
The manual gives no further step on this screen; its troubleshooting table points leaks from a wrong-size or badly positioned mask to your home care provider.
More on this, and what other makers’ machines show: Mask fit result.
Source: Luna G3 APAP / Luna G3 CPAP User Manual (React Health, V1.7, issue date February 29, 2024), checked 2026-09-29.
React Health Luna G3 An icon on the screen
Humidifier icon with a number
The number next to the humidifier icon on the main screen is the humidity level. 0 means the humidifier is off.
No action is needed.
More on this, and what other makers’ machines show: Humidifier and humidity icons.
Source: Luna G3 APAP / Luna G3 CPAP User Manual (React Health, V1.7, issue date February 29, 2024), checked 2026-09-29.
React Health Luna G3 Words on the screen
Humidifier Failure!!
When the humidifier is fitted, an audible alert sounds when it fails to work, and the screen shows “Humidifier Failure!!”.
The alert table gives no step. The manual’s general line: if none of the troubleshooting actions solves a problem, contact your home care provider.
More on this, and what other makers’ machines show: Humidifier fault.
Source: Luna G3 APAP / Luna G3 CPAP User Manual (React Health, V1.7, issue date February 29, 2024), checked 2026-09-29.
React Health Luna G3 An icon on the screen
Heated tubing icon turns into a number
When the heated tubing is connected correctly, its icon on the main screen becomes a number: the heat level, one of five. A 3 next to the icon means level 3.
No action is needed.
More on this, and what other makers’ machines show: Heated tube.
Source: Luna G3 APAP / Luna G3 CPAP User Manual (React Health, V1.7, issue date February 29, 2024), checked 2026-09-29.
React Health Luna G3 An icon on the screen
Signal icons: strong, moderate, weak, no signal found
With the optional Cellular Module fitted, one of four signal icons appears in the status bar. With a weak signal, data sending may slow down or stop; the module keeps searching until it finds a signal. No icon at all can mean the module is not connected properly or not working.
What React Health says to do
- React Health warns not to place computers, televisions, radios or similar devices near the Cellular Module.
More on this, and what other makers’ machines show: Wireless or cellular signal.
Source: Luna G3 APAP / Luna G3 CPAP User Manual (React Health, V1.7, issue date February 29, 2024), checked 2026-09-29.
React Health Luna G3 Words on the screen
SD Card Full! / Reinsert SD Card!
“SD Card Full!” shows when the SD card has reached its maximum capacity. “Reinsert SD Card!” shows when the SD card fails to work.
The alert table gives no step beyond the message itself. If a problem persists, React Health says to contact your home care provider.
More on this, and what other makers’ machines show: SD card and data card.
Source: Luna G3 APAP / Luna G3 CPAP User Manual (React Health, V1.7, issue date February 29, 2024), checked 2026-09-29.
React Health Luna G3 Words on the screen
Device Fault!!!
An audible alert: no airflow is coming out of the machine. The screen shows “Device Fault!!!”.
The alert table gives no step. React Health’s troubleshooting table says to unplug the power cord and plug it back in 20 seconds later when the screen shows nothing or the machine will not start, and to contact your home care provider when no cause can be found.
More on this, and what other makers’ machines show: System fault and error codes.
Source: Luna G3 APAP / Luna G3 CPAP User Manual (React Health, V1.7, issue date February 29, 2024), checked 2026-09-29.
React Health Luna G3 Words on the screen
Power Failure!!!
An audible alert that sounds 6 seconds after the machine loses power while it is delivering air. It does not sound if power is lost in standby, and nothing is shown on the screen during a power failure.
The alert table gives no step. React Health notes that when power comes back the machine returns to the state it was in before the interruption.
More on this, and what other makers’ machines show: Power and voltage alerts.
Source: Luna G3 APAP / Luna G3 CPAP User Manual (React Health, V1.7, issue date February 29, 2024), checked 2026-09-29.
React Health Luna G3 Words on the screen
Low Input Voltage!!
The voltage from the power adaptor is lower than 22 V; an audible alert sounds.
The alert table gives no step. Its troubleshooting table says to make sure the power cord, power adapter and machine are connected properly, and to contact your home care provider if no cause can be found.
More on this, and what other makers’ machines show: Power and voltage alerts.
Source: Luna G3 APAP / Luna G3 CPAP User Manual (React Health, V1.7, issue date February 29, 2024), checked 2026-09-29.
React Health Luna G3 Something the machine does
Air from the machine is unusually hot
The air inlet may be partly blocked, so too little air is getting into the machine.
What React Health says to do
- Replace the air filter (or the optional ultra-fine filter) and clean the air inlet.
- Put the machine where air flows freely, at least 20 cm from walls, curtains and other objects.
More on this, and what other makers’ machines show: Tubing or air inlet blocked.
Source: Luna G3 APAP / Luna G3 CPAP User Manual (React Health, V1.7, issue date February 29, 2024), checked 2026-09-29.
React Health Luna G3 Words on the screen
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.
What React Health says to do
- Replace the filter, then reset its use time under Accessories in the patient menu.
More on this, and what other makers’ machines show: Replace filter, tubing or mask reminders.
Source: Luna G3 APAP / Luna G3 CPAP User Manual (React Health, V1.7, issue date February 29, 2024), checked 2026-09-29.
React Health Luna G3 Words on the screen
Please Replace Tubing!
The same for the tubing: the preset replacement time has been reached and the tubing has not been replaced.
What React Health says to do
- Replace the tubing, then reset its use time under Accessories.
More on this, and what other makers’ machines show: Replace filter, tubing or mask reminders.
Source: Luna G3 APAP / Luna G3 CPAP User Manual (React Health, V1.7, issue date February 29, 2024), checked 2026-09-29.
React Health Luna G3 Words on the screen
Please Replace Mask!
The same for the mask.
What React Health says to do
- Replace the mask, then reset its use time under Accessories.
More on this, and what other makers’ machines show: Replace filter, tubing or mask reminders.
Source: Luna G3 APAP / Luna G3 CPAP User Manual (React Health, V1.7, issue date February 29, 2024), checked 2026-09-29.
Sources
React Health’s own user guides only, read on the date shown.
- React Health: Luna G3 APAP / Luna G3 CPAP User Manual — V1.7, issue date February 29, 2024. www.reacthealth.com Checked 2026-09-29.