React Health Luna CPAP — Setup, Common Issues, and Getting Started

Welcome. If you have a React Health Luna G3 or Luna II CPAP machine, this guide will help you get set up correctly and resolve the issues new users encounter most often. About the Luna CPAP Series. React Health, formerly known as 3B Medical, manufactures the Luna G3 Auto CPAP and the Luna II CPAP. These machines are known for their simple, easy-to-read displays and quiet operation. The Luna G3 supports auto-titrating pressure (APAP mode), meaning it adjusts pressure automatically throughout the night. Step 1: Connect the humidifier. The Luna G3 and Luna II use a removable humidifier chamber that attaches to the side of the machine. Align the chamber with the slot, push it in until it clicks, and fill it with distilled water to the max fill line. Do not use tap water. Step 2: Connect the tubing. The standard 22mm tubing connects to the air outlet on the front of the machine. Press and twist to lock. Attach your mask at the other end. Step 3: Set the ramp time. The Luna G3 and Luna II both offer a ramp feature that starts therapy at a lower pressure and gradually increases over 5 to 45 minutes. This makes it easier to fall asleep. Access ramp settings through the menu button on the machine. A ramp time of 20 to 30 minutes is comfortable for most users. Step 4: Adjust pressure (if your prescription allows). If you have a Luna G3 in APAP mode, your prescription specifies a minimum and maximum pressure range. The machine automatically chooses the best pressure within that range. If you feel the pressure is too high or too low throughout the night, contact your prescriber — do not change the min/max settings yourself without medical guidance. Step 5: Start therapy with SmartStart. The Luna G3 supports SmartStart — the machine starts automatically when it detects breathing through the mask. You do not need to press a button. To enable this, navigate to the Settings menu and enable SmartStart. Step 6: Review your data. The Luna G3 has a built-in SD card slot. Remove the SD card and insert it into your computer to view therapy data using SleepyHead or OSCAR (free software). Some Luna G3 models also support the myEnAble app via Bluetooth. Step 7: Common first-night issue — feeling like you cannot exhale. This is normal and temporary. The pressure resistance during exhale is an adjustment for new users. If it feels overwhelming, enable the Exhale Pressure Relief (EPR) feature in the menu. EPR reduces pressure slightly during exhalation. Still need help? Find a CPAP provider near you →