CPAPtalk.com

zoocrewphoto wrote:

Sclark08 wrote:Ever since I have had my resmed S9 auto machine the humidifier never uses hardly any water. I usually dump every day but I left it for 3 days and the water level never changed
Think I need a trip to DME. I have the option to set my own or use auto with temp adjust and still same result!

What settings have you tried?

I use the S9 autoset with my temp set low at 68, but my humidity set to 5. I can use a full tank of water in about 10 hours, so most nights of 6-8 hours, i use over a half a tank easily. I live in Seattle with moist climate, so I had to set it manually to get the humidity I want. Have you tried manually setting it? If not, I would try that. Otherwise, I would be contacting the DME.

Oh man, I forgot we can manually adjust our humidity. I need to look that up when I get home. I'm used to my old PR machine that actually had a humidity knob, my S9 is new to me, I cranked it up but forgot I was only adjusting the hose temp. I also live in the Seattle area and mine doesn't seem humid enough, waking up a little dry in the nose. I didn't realize the machine varied the humidity based on the environment, I thought it would use the same amount of water in Seattle or in Arizona. I fill my tank up every other day (16 hours total use) and there's just a little bit left in the bottom.

But yeah, if I'm draining my tank every other day in Seattle and I'm still a little dry, I'd think something is wrong with the water level not changing unless you live in the rainforest. Could it have accidentally been turned off in the settings?

OhHelpMe wrote: But the variance you mention sounds like something else. I suspect large mask leak on the nights the chamber was entirely consumed. Your profile says you are using CPAP at pressure 4.8. It's hard at that pressure to consume a tank of water in one night unless you live in a desert or there is something wrong with your CPAP process. Are you indeed using a FFM as your equipment profile says?

Yes I am using a FFM at 4.8 pressure. No significant mask leaks (max 95% value of 4.8 since starting, usually lower). I think my large water consumption variance is due to a large range in sleep times (anywhere from 6 to 10 hours), ambient temp & humidity (windows open vs. the a/c on and we have had a lot of weather changes even in the last 2-3 weeks), and probably variability in mouth breathing (typically all night but possibly less).

There was only one night the tank was emptied and it was a night I slept longer. But I have had longer sleep times it used less water than I'd expect, and shorter sleep times it used more. I was saying I was surprised it wasn't completely empty more often since I have the humidity maxed out and the temp fairly high, and I had heard of folks having theirs run dry. i wasn't aware water consumption also varied on pressure, so thanks for that info.

I have enough variables that at this time I don't think there is anything else going on. I just wanted to add my story and how I tested my humidifier to assure myself it was working (or at least heating up and responding to changes in settings up & down). Thanks!

I had to go into the clinical menu on my S9 Autoset to get the humidity control (previously it only had temp control, which is apparently maintaining 80% humidity automatically). I assumed the manual setting of 6 would give more humidity than the automatic setting, but I'm not sure. Best wishes.

Pasta wrote:But yeah, if I'm draining my tank every other day in Seattle and I'm still a little dry, I'd think something is wrong with the water level not changing unless you live in the rainforest. Could it have accidentally been turned off in the settings?

Unlikely that the humidifier portion got turned off and temperature selection was left on...not impossible but unlikely.
That would entail manual mode selection and not something that one normally does by accident.

In general:
Water consumption using the machines in "automatic" humidity delivery mode, with the heated hose, is simply going to vary with the ambient humidity.
With the S9 and the ClimateLine hose the default automatic deliver is for the machine to maintain 80% delivered humidity.
How much water gets used maintaining that 80% is going to depend on how much water is in the incoming air...ambient humidity.
Just because someone lives in a rain forest doesn't mean the ambient humidity inside the house is the same as outside the house.

Big leaks and higher pressures can also affect water consumption.

PR S1 heated hose...and the various settings available work on the same principle as the S9 with CLimateline in automatic humidity delivery mode except there are more choices for the "automatic" % of humidity to be delivered as opposed to the S9's 80% in automatic mode.
Water consumption is still mainly going to depend on the ambient room humidity.
It's physics.

On the nights that I sleep with the windows open and it rains....I don't use any water and I always max out humidity as that is what my nose likes.
On nights that I close the windows and it rains outside...I use a little water.
On nights that it doesn't rain and I close the windows...I might use half a tank....some nights I might use 3/4 the tank...on a rare occasion I have used all the water.
On nights with windows open and no rain...water consumption will vary depending on ambient humidity.
My window is close to my bed and my machine....tiny bedroom.

Of course machines do fail and when in doubt....especially when under warranty...check with equipment supplier.

Also....those heated hoses fail...that's not uncommon. If the sensors aren't working properly then there's no telling what the water consumption is going to be. Wires break and connections crap out.

In general though...your nose should alert you to a problem with not getting adequate moisture.

Sclark08 wrote:I reset my temp to 62 and my humidity to 4. hopefully that will help. I called my DME and she said the check is let it warm up take the reservoir out and see if it at lease feels warm. I don't want warm I want COOL!

That's pretty chilly to get super humid air. Cold air cannot physically hold as much water as warm air. With my S9, living in a cold dry climate, I find a temperature about 5-7 degrees Celsius above room temp I use a little over half a tank each night for about 7-8 hours at 8cm pressure. Based on the laws of thermodynamics, lower temp and pressure would hold less water used, higher temp and pressures (more air passing over the water per second) means more water used. With your cold temp setting I would not expect you to use much water at all, especially if your pressure is less than 10cm. Recently I changed pressure to 8-14, with my 90% around 11 and I am seeing more water use, but only a bit.

When I started cpap in February here in frigid Minnesota my water tank ran completely dry every night, and it wasn't until about 6 weeks ago that the tank started leaving water in the tank... it's 80 degrees today, so now for the summer I won't be using as much water... it all depends on where you live, whether it's a rainy month or a dry month (humidity vs. no humidity in the air).

Pugsy wrote: Water consumption using the machines in "automatic" humidity delivery mode, with the heated hose, is simply going to vary with the ambient humidity.
With the S9 and the ClimateLine hose the default automatic deliver is for the machine to maintain 80% delivered humidity.
How much water gets used maintaining that 80% is going to depend on how much water is in the incoming air...ambient humidity.

It seems you have a pretty good understanding of psychrometrics - but is there really a humidistat in the machine somewhere with an 80% setpoint? I figured the heated plate was just a constant temperature and you get whatever RH you get. The readout on my machine just says something like Humidity level 3, 80w.

sc0ttt wrote:is there really a humidistat in the machine somewhere with an 80% setpoint? I figured the heated plate was just a constant temperature and you get whatever RH you get. The readout on my machine just says something like Humidity level 3, 80w.

ResMed says there is a sensor for humidity. I didn't ask where that sensor was though when I talked to a ResMed tech about this 80% no matter what temperature because I was having a hard time wrapping my brain around it myself. I did chat with a tech about how the S9 did what they say it will do. Sensors are indeed involved but I didn't think to ask where the sensors are but I would assume at least one at the machine level.

When using the ClimateLine hose attached and the default setting to "automatic" they say it delivers 80% at no matter what temperature. I have no reason to doubt them and no desire to test it since it suits my needs whatever it is doing. There's probably some sort of official documentation somewhere in the bowels of all the literature or patents but I don't need to see it.

Now if you see humidity level of 3....that's not automatic setting and I don't know what level of humidity that is supposed to deliver. It may depend in part on the ambient room humidity meaning my level 3 setting might deliver a different % of humidity than your setting of 3 where you live.

If a person doesn't have a Climateline hose...all they get to choose from in terms of humidity selection would be 1 through 6 settings and as far as I know all that does is regulate the heat to the bottom of the tank. I don't know if there is any sensing going on when using that mode of operation. I didn't ask about that. My questions pertained to using the ClimateLine.

These new generation machines like the S9 and the PR S1 with the humidity sensors (where ever they happen to be) are so much better than the old machines where all we had was heat going to the plate to warm the water.
I know the PR S1 50 series machines had a humidity sensor in the machine itself and they didn't even have a heated hose option because they offered 2 separate modes of humidity delivery. Again they didn't go into a lot of specific details on how they came to determine how it worked but there was a sensor for humidity at the machine level.