ResMed · Auto CPAP (APAP)
ResMed S9 series (S9 AutoSet, S9 Elite, S9 Escape)
The S9 series was ResMed's bedside machine family before the AirSense 10: the S9 AutoSet and S9 Escape Auto adjust pressure automatically, while the S9 Elite and S9 Escape deliver a fixed CPAP pressure, all within 4 to 20 cm H2O. Most were paired with the H5i heated humidifier, which clips onto the side, and the ClimateLine heated tube for Climate Control. The machine has a color screen, a push dial and an SD card that records your therapy data.
ResMed announced the S9 series (starting with the S9 AutoSet and S9 Elite) in its February 4, 2010 earnings release, with launches in Europe and the Americas that quarter. Its successor platform, the AirSense 10, was introduced on August 18, 2014. The S9 is no longer sold new; repair site iFixit reports it was discontinued in 2016, but we did not find a ResMed notice giving an exact date. ResMed states myAir is not compatible with S9 machines.
Specifications
| Noise | 24 dBA (ISO 17510-1:2002); 26 dBA with uncertainty of 2 dBA (ISO 17510-1:2007) |
|---|---|
| Power | 90W power supply (needed with the H5i) or 30W travel power supply (machine only), 100 to 240 V, 50 to 60 Hz; optional Power Station II battery pack and DC/DC Converter 24V/90W |
| Weight | 1.8 lb (835 g) for the S9; H5i with unfilled standard tub adds 1.52 lb (0.69 kg) |
| Display | Color LCD with push dial, Home, Info and Setup keys |
| Data card | SD card (supplied) |
| Dimensions | S9: 6.0 x 5.5 x 3.4 in (153 x 140 x 86 mm); H5i: 6.0 x 5.7 x 3.4 in (153 x 145 x 86 mm) |
| Humidifier | Optional H5i heated humidifier (380 mL to the max line), humidity Off to 6; Climate Control with ClimateLine or ClimateLineMAX heated tubing |
| Connectivity | SD card; module/adapter port for ResMed accessories only; no built-in wireless |
| Pressure range | 4 to 20 cm H2O |
Key features
- S9 AutoSet and S9 Escape Auto: auto-adjusting pressure; S9 Elite and S9 Escape: fixed CPAP
- S9 AutoSet for Her variant
- EPR (Expiratory Pressure Relief) levels 1, 2 or 3
- Adjustable Ramp
- SmartStart/Stop (S9 AutoSet and S9 Elite only)
- Mask-fit test (S9 AutoSet and S9 Elite only)
- H5i heated humidifier with warm-up and Climate Control
- ClimateLine and ClimateLineMAX heated tubing
- SD card data recording
- S9 Essentials simplified menu (clinician option)
- Meets FAA RTCA/DO-160 requirements for all phases of air travel
Strengths and trade-offs
Strengths
- Standard 22 mm air outlet (ISO 5356-1) works with common ResMed masks and standard tubing.
- The SD card records detailed data that you can view yourself in OSCAR.
- At 1.8 lb the machine alone is light enough to travel with, using the 30W travel power supply.
- The H5i is detachable, so you can travel with just the machine.
- Climate Control with ClimateLine tubing is designed to reduce condensation in the tube.
Trade-offs
- Discontinued: no new units, and parts such as H5i tubs and ClimateLine tubing may be harder to find.
- Not compatible with myAir, so there is no phone app for your data.
- No built-in wireless, so your provider needs the SD card for detailed reports.
- SmartStart/Stop and mask-fit are not available on the S9 Escape and S9 Escape Auto.
- The H5i must not be used on an aircraft and needs the 90W power supply.
- ResMed's servicing note describes a five year design life, and most S9 units are well past that.
Comfort settings you can change
These are in the patient menu. Your prescribed pressure and therapy mode are set by your clinician and are not covered here.
Ramp time
Starts at a low pressure and raises it to your treatment pressure over the time you choose, to help you fall asleep.
How to change it: From the Home screen, turn the dial until the Ramp screen shows in blue, press the dial (it turns orange), turn to the ramp time you want and press to confirm.
Humidity level (H5i)
Sets how much the H5i heats the water, from Off to 6. Higher means more moisture.
How to change it: From the Home screen, turn the dial to the Humidity Level screen, press, turn to the level you want and press to confirm. If water collects in the tube or mask, turn it down.
Climate Control and heated tube temperature
Available only with ClimateLine or ClimateLineMAX heated tubing. It adjusts air temperature and humidity to cut down on condensation; you can set the tube temperature for comfort.
How to change it: From the Home screen, turn the dial to the Climate Ctrl screen, press, turn to the temperature you want and press to confirm. If the air feels too warm or too cold, turn the heated tube temperature down or up the same way. ResMed notes the displayed temperature and humidity values are settings, not measurements.
H5i warm-up
Preheats the water in the tub before you start therapy.
How to change it: Go to the humidity level screen and push and hold for three seconds as shown in the Welcome Guide until the Warming Up bar appears. Hold again for three seconds to cancel, or just press Start/Stop to begin therapy.
Mask type
Tells the machine which kind of mask you use so it handles leak and SmartStart correctly.
How to change it: Press the Setup key, turn the dial until Mask is blue, press, turn to your mask setting and press to confirm. Not available if your clinician enabled S9 Essentials.
Tube type
Matches the machine to SlimLine or Standard tubing so it delivers the right pressure at the mask.
How to change it: Select the tubing you actually use in the Setup menu. ResMed lists the wrong tube selection as a cause of air feeling too weak.
SmartStart/Stop
Starts therapy when you breathe into the mask and stops it when you take the mask off. S9 AutoSet and S9 Elite only.
How to change it: If it is available to you, enable or disable it in the Setup menu. ResMed advises turning it off if you use nasal pillows at a set pressure below 7 cm H2O, because the machine may not stop when you remove the mask.
EPR (Expiratory Pressure Relief)
Lowers the pressure as you breathe out so exhaling feels more natural. ResMed offers level 1 (mild), 2 (medium) or 3 (maximum).
How to change it: Whether you can change EPR yourself depends on how your clinician set up the machine. If you think a different EPR level would help, ask your equipment provider or prescribing clinician.
Cleaning and care
Every day: tubing and water tub
Pull the air tubing off by the finger grips on the cuff and hang it in a clean, dry place out of direct sunlight, which can harden and crack it.
Take out the water tub, pour out leftover water, unclip its four side latches and pull the lid and base apart. Wash both in warm water with mild detergent, rinse well and let them air dry out of direct sunlight.
Every week: wash the tubing
Remove the tubing from the machine and the mask, wash it in warm water with mild detergent, rinse it thoroughly and hang it to dry. Do not put it in a washing machine or dishwasher.
Every month: machine, filter and lid seal
Wipe the outside of the S9 and H5i with a damp cloth and mild detergent. Check the air filter for holes or dirt.
Peel the flip lid seal off the H5i flip lid and wash it in warm water with mild detergent. Replace it if it is cracked or torn.
As needed: white deposits in the tub
Clean white mineral deposits from the water tub with a solution of one part household vinegar to 10 parts water, then rinse well.
Replace the tub if any part leaks or has become cracked, cloudy or pitted.
Every six months: air filter
Remove the air filter cover from the back of the S9, throw away the old filter, put in a new ResMed filter so it sits flat, and replace the cover. Do not wash the filter; it is not reusable. Change it sooner if it is dirty.
What not to use
ResMed says not to use bleach, chlorine, alcohol, aromatic solutions, moisturizing or antibacterial soaps or scented oils on the machine, humidifier or tubing, and not to add scented oils or perfumes to the water.
Replacement parts
- Tubing
- SlimLine (6 ft, 15 mm), Standard (6 ft 6 in, 19 mm), ClimateLine heated (6 ft 6 in, 15 mm) or ClimateLineMAX heated (6 ft 3 in, 19 mm). The air outlet is a standard 22 mm conical connector.
- Filters
- S9 standard air filter (polyester fiber) or hypoallergenic filter. Not washable; replace every six months or sooner.
- Water chamber
- H5i standard water tub or H5i cleanable water tub (380 mL to the maximum line), plus the H5i flip lid seal.
- Replacement notes
- Replace the water tub if it leaks or turns cracked, cloudy or pitted, and the flip lid seal if it cracks or tears. ClimateLine tubing connects to the H5i, not directly to the S9. Because the S9 is discontinued, check with your supplier which S9 and H5i parts they still stock.
Troubleshooting
The screen is blank
Check that the power cable is connected and the outlet is on, push the DC plug fully into the back of the machine, and make sure the S9 and H5i are firmly clicked together.
Not enough air is coming out
Ramp may be running; wait or shorten the ramp time. Replace a dirty air filter, check the tubing for kinks or holes, close the H5i flip lid until it clicks, make sure the flip lid seal is the right way up, and confirm the tube type selected in the menu matches your tubing.
The machine does not start when I breathe into the mask
Take a deeper breath, fix any big mask leak, and check that SmartStart/Stop is enabled. The S9 Escape and S9 Escape Auto do not have SmartStart/Stop, so press Start/Stop.
The machine does not stop when I take my mask off
SmartStart/Stop may be off, or your mask may not be one ResMed recommends. With nasal pillows at a set pressure below 7 cm H2O, ResMed says to turn SmartStart/Stop off and use the button.
The pressure rises when I talk or cough
Avoid talking with a nasal mask on and breathe normally; an auto machine reacts to unusual breathing. If the cushion is buzzing against your skin, adjust the headgear.
Water is splashing on my face
The tub may be overfilled; keep the water below the maximum mark. If condensation is forming in the tube and mask, turn the humidity down, and keep the H5i below the level of your head.
The water tub is leaking
Check the cleanable tub is assembled correctly with all four latches clipped. If the tub is cracked or damaged, it needs replacing.
The air in the mask feels too warm or too cold
With ClimateLine or ClimateLineMAX tubing, turn the heated tube temperature down or up in the menu.
The machine keeps blowing air after I stop
This is normal. The S9 can blow air for up to an hour after therapy to cool the H5i heater plate. You can unplug it if you want it to stop.
Travel and power
ResMed confirms the S9 series meets FAA requirements (RTCA/DO-160) for all phases of air travel. Both ResMed power supplies accept 100 to 240 V at 50 to 60 Hz and list a nominal 115 V, 400 Hz rating for aircraft use. The 30W power supply runs the machine only and is the one ResMed recommends for travel; the 90W supply is needed if you bring the H5i.
Do not run the H5i on an aircraft, because water can get into the machine and tubing during turbulence; empty the tub and detach the H5i with its release button before you travel. If you leave the H5i at home, pack SlimLine or Standard tubing, since ClimateLine and ClimateLineMAX do not connect directly to the S9. For DC power, ResMed sold the optional Power Station II battery pack and a DC/DC Converter 24V/90W for the S9; because the S9 is discontinued, check what your supplier can still provide, and bring the power cord for the region you are visiting.
Your sleep data
The S9 records your therapy on the SD card that came with it, and you can see daily or cumulative usage on the machine itself by pressing the Info key on the Home screen (unless your clinician enabled S9 Essentials, which hides the Info menu). Your provider may ask you to unplug the machine, push the SD card in to release it, put it in the protective folder and mail it to them. The same card can carry settings updates back from your clinician; wait for the Settings updated successfully message after you reinsert it.
ResMed's myAir app does not work with S9 machines; ResMed directs S9 users to their equipment provider for detailed reports. OSCAR, the free data viewer, includes support for ResMed S9 data in its ResMed loader, so you can read the SD card on a computer. Copy the card, then put it back in the machine so recording continues.
Supplies that can help
Distilled water is what most CPAP humidifier chambers are meant to be filled with, because it leaves little or no mineral scale behind.
The air inlet filter keeps dust and lint out of the machine and your airway; it is a cheap part that needs regular replacement.
The plain hose between the machine and the mask; it wears out and should be replaced on a regular schedule.
Plain, mild dish soap is the cleaning agent most CPAP makers and the FDA point to for masks, tubing and humidifier chambers.
A long, flexible brush sized to reach the full length of CPAP tubing so you can scrub the inside, not just soak it.
A simple hook or hanger for drying CPAP tubing vertically after washing, and for keeping it off the floor.
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Frequently asked questions
Is the ResMed S9 still supported?
The S9 is no longer sold new; ResMed's AirSense 10 replaced it as the main platform in 2014. ResMed still publishes S9 guides, but myAir does not support the S9, and parts depend on what suppliers still stock. ResMed's servicing note describes a five year design life, so an S9 still in use is well past it.
Does the S9 work with myAir?
No. ResMed says myAir is for AirSense 10 and AirCurve 10 machines and is not compatible with the S9. You can view usage on the S9 screen through the Info key, and ask your equipment provider for a detailed report from the SD card.
Can I read my S9 SD card in OSCAR?
Yes. OSCAR's ResMed loader includes S9 support, so you can copy the SD card on a computer and open it. Put the card back in the machine afterward so it keeps recording.
Can I use the S9 without the H5i humidifier?
Yes. The S9 runs on its own with SlimLine or Standard tubing and the 30W travel power supply. ClimateLine heated tubing needs the H5i, because it connects to the humidifier rather than the machine.
What does 'Humidifier fault, replace humidifier' mean on an S9?
It can mean the machine got too hot, the H5i was refilled with cold water while still hot, it was filled with ice cold or hot water, or the H5i has failed. Let it cool, use room temperature water, and restart by unplugging and replugging the power cord. If it keeps happening, stop using the H5i and contact your provider.
Which S9 models have SmartStart and mask-fit?
The S9 AutoSet and S9 Elite have SmartStart/Stop and the three-minute mask-fit test. The S9 Escape and S9 Escape Auto do not, so on those models you start and stop therapy with the button.
Sources
- document.resmed.com
- thecpapshop.com
- thecpapshop.com
- static.helpjuice.com
- document.resmed.com
- investor.resmed.com
- investor.resmed.com
- ifixit.com
- ap.resmed.com
- gitlab.com
Last reviewed October 11, 2026. How we research · Report an error