operational temperature

Hi, can anybody tell me what the minimum ambient temperature can be for using my cpap machine? and if it is unhealthy for me or is it just bad for the machine. I was camping with uncle in a tent and the temperature dropped under frezzing.

Thank you for your help.

I have never seen a minimum operating temp...only don't expose machine to temps over 140 degrees.
I can't see other than greatly increased chance of rain out that there would be any great negatives to using the machine when temps are below freezing. There might be something at the website for your machine's manufacturer that addresses this issue. I have never seen anything but then I haven't really looked either. Only thing was a quick check just now at cpap.com machine specs.

Must be uncomfortable blowing below freezing air into your lungs

You didn't say which machine or manufacturer.
In any case, the information should be listed in the user manuals.

Here are some listings copied from the Respironics and ResMed manuals from some previous and current generations of machines.

Respironics

Legacy:

ENVIRONMENTAL:
Operating Temperature 41 to 95°F (5 to 35°C)
Transport & Storage Temperature -4 to 140°F (-20 to 60°C)
Humidity (Operating / Storage) 15 to 95% non-condensing
Outlet Air Temperature Shall not exceed 106°F (41°C) when
operating at a maximum ambient
temperature of 95°F (35°C).
Atmospheric Pressure 83 to 102 kPascals
Elevation Tested at 0 to 5500 ft.
Sound Pressure Level 30 dB(A)

System One

Environmental
Operating Temperature: 5° to 35° C (41° to 95° F)
Storage Temperature: -20° to 60° C (-4° F to 140° F)
Relative Humidity (operating & storage): 15 to 95% (non-condensing)
Atmospheric Pressure: 101 to 77 kPa (0 - 2286 m / 0 - 7500 ft)




ResMed

S8

Environmental Conditions
Operating Temperature: +41°F to +104°F (+5°C to +40°C)
Operating Humidity: 10%–95% non-condensing
Storage and Transport Temperature: -4°F to +140°F (-20°C to +60°C)
Storage and Transport Humidity: 10%–95% non-condensing
Operating Altitude: sea level to 8500’ (2591 m)

S9

Operating temperature +41ºF to +95ºF (+5ºC to +35ºC)
Operating humidity 10–95% non-condensing
Operating altitude Sea level to 8,500’ (2,591 m)
Storage and transport
temperature
-4ºF to +140ºF (-20ºC to +60ºC)
Storage and transport
humidity
10–95% non-condensing


.

The +41ºF +5ºC lower limit is about condensation control. Remember when hot and cold air meet, you get condensation on the warm side. Which is inside your cpap machine.

If the air is dry enough, there doesn't seem to be anything that should be a major problem until -4ºF -20ºC and I expect that is the point where the plastic and rubber breaks if you look at it wrong. Of course dry air that is that cold will have so much charge you might have static problems on your mask even if you could stand to breath it.

Quick application of Charles law... derived from PV=nRT
At freezing, +32ºF 0ºC a cpap at a setting of 20 will raise the pressure enough to increase the temperature 5.3ºC or 9.5ºF so if the dew point is about 10ºF away from the air temperature, water will condense inside the machine just from the pressure change. I'm guessing the machine will be warmer from the spinning motor and electronics and hot plate if your using a heated humidifier.

-tim wrote:The +41ºF +5ºC lower limit is about condensation control. Remember when hot and cold air meet, you get condensation on the warm side. Which is inside your cpap machine.

If the air is dry enough, there doesn't seem to be anything that should be a major problem until -4ºF -20ºC and I expect that is the point where the plastic and rubber breaks if you look at it wrong. Of course dry air that is that cold will have so much charge you might have static problems on your mask even if you could stand to breath it.

Quick application of Charles law... derived from PV=nRT
At freezing, +32ºF 0ºC a cpap at a setting of 20 will raise the pressure enough to increase the temperature 5.3ºC or 9.5ºF so if the dew point is about 10ºF away from the air temperature, water will condense inside the machine just from the pressure change. I'm guessing the machine will be warmer from the spinning motor and electronics and hot plate if your using a heated humidifier.

No, you're taking outside air with whatever absolute humidity there is in the outside air and compresssing it and warming it. Even if the outside air is at 100% humidity, it will not condense unless it hits an area with lower temperature or pressure than the outside air.

However, when you exhale, some of the exhaled air flows back up the hose. You might get condensation in the hose or even the machine from your exhaled breath even if there's no humidifier.

It's possible that a very low temperature would be outside the calibration/operational range of the airflow and pressure sensors.

You used your machine; you woke up.
I'd call that a good night.