DIY larger humidifier tank / expansion for Resmed Airsense 10

So like some others here, there have been times where I've run out of humidifer water on my Airsense 10 [one relevant thread here: http://cpaptalk.com/viewtopic.php?f=1&t ... k#p1042400.

I did some research and found a thread on the apneaboard forum that someone came up with a DIY solution for this -- full credit to RonKMiller there for the idea and full description of how to do it.

RonKMiller's instructions are here: http://www.apneaboard.com/forums/Thread ... #pid150798 and spot on / easy to follow. Only difference is you need (4) Watts quick connect 1/4" x 1/8" PL-3004; 2 for the Rubbermaid container and 2 for the stock humidifer container (not sure why he said you only needed 2). Obviously this requires some level of DIY capability and some basic tools but it really was pretty easy (though I am very into tools/construction/etc).

I wanted to share this here for awareness; I did this myself with a slight modification, using a Rubbermaid Brilliance container rather than RonKMIller's Nalgene container - http://www.rubbermaid.com/en-US/brillia ... containers. I actually tried the Nalgene container at first but found it made 'crinkling' noises as it was used, and it's a tight fit with that top and the two fittings. I also find the Rubbermaid container easier to open and close to fill since the fittings are on the side vs on the top. I've been using it for 2-3 weeks, and it seems to work great - the Rubbermaid container is definitely airtight and it has 2 latches to secure it down as well as a rubber gasket. The only downside is it can be a little difficult to pry open to refill. I fill the Rubbermaid container each night, and that drains into the stock humidifer reservoir (so I never pull that out).

Here's a picture of my solution with the cover off. Note that my implementation isn't perfect. Ideally the height of the input line from the Rubbermaid container is as low as possible, but higher than the stock Resmed humidifier container to ensure it drains down via gravity. Mine works, but could be better - I placed the Rubbermaid on a piece of scrap wood for now and would probably re-engineer this / plan it a little better (perhaps a small stand to put the Rubbermaid container on).
You also have to be aware of the max fill of your Rubbermaid container to make sure you don't overflow the CPAP machine itself.

You will sacrifice your existing Airsense humidifer tank if you do this (by drilling holes/installing fittings) so I would recommend having a spare just in case. But this worked for me first time with no issues.

Happy to answer any questions based on my experience, but again full thanks to RonKMiller for coming up with this.

jdm5 wrote: ↑

Sun Nov 18, 2018 2:04 pm

so I would recommend having a spare just in case. But this worked for me first time with no issues.

Cool... my only comment is... always have a spare of everything!

My water usage only exceeds the capacity of the tank when my cpap is run more than 9 hours.
If it runs dry, I either forgot to top it off or it is time to get my lazy butt out of bed.
Even in winter, when the ambient humidity is as low as 7%.
A nice hack can help when the manufacturer has failed-
-or the patient is unable to add water when needed.

I am sure I am missing something really obvious, but why are there two tubes between the reservoirs? Isn't one tube placed down as low as possible with a 0 degree incline enough? What is the point of that tube way high up there? The other guy's post mentioned he thought it probably wasn't necessary either.

Anything you notice about this setup confusing the machine's pressure sensing? I would think not. Perhaps so long as there is no direct path to open air, the second reservoir might not even need an airtight lid? (For example, in the photo the upper tube would provide a path to open air without a lid on the second reservoir, right?)

I would probably be willing to pay someone to make this. Someone start a business and I'd be your first customer. I spend more than 10 hours in bed and desire max humidity for my sinuses.

why are there two tubes between the reservoirs?

Like the official reservoir, the expansion container is sealed on top to enable the machine to pressurize.
The bottom tube carries water out of the expansion box, the top tube carries air into it to take the place of the water.
Topologically speaking, the two containers are one big container.

HTH,
Dave

metallikat36 wrote: ↑

Tue May 14, 2019 8:37 pm

I am sure I am missing something really obvious, but why are there two tubes between the reservoirs? Isn't one tube placed down as low as possible with a 0 degree incline enough? What is the point of that tube way high up there?

If you only had one tube, when you turned on the machine, the difference in air pressure would blow all the water into the reserve tank, then when you turned the CPAP off, all that water would come squirting back.

Thanks so much to jdm5 and RonKMiller's important work in the world of sleep comfort.

Just upgraded from an AirSense 10 to an AirSense 11. I'm lucky enough to make it through the night. But if you have trouble with the capacity of the 10, wait till you try an 11. I immediately started looking for an upgrade tank and came upon this thread. See my implementation of this with mods below. Pictures no longer allowed on this board.

I used to be able to go about 5 days with my AirSense 10 on auto. With an 11, I can just about squeeze in 3 nights on a full tank.

Call me lazy or unsanitary, but I'd like a tank to last about a week before taking the cpap machine apart. So I followed these steps and tried a little variation with one hose first, to see how it went. And it worked ok.

I tried to make the water run downhill from the expansion tank, and in to the lowest point on the built-in humidifier tank. I ended up with a one gallon Rubbermaid Brilliance container, because it was the same price as the next one down. I don't suppose I'll ever fill it up, but the tall size makes it easy to refill next to the bed. And it looks like I can add a lot of water without issue. I had some trouble with leaks when the system was pressurized. I ended up using a little aquarium grade silicone adhesive on the threads and the seal is good now. I put the whole thing on a cafeteria tray by my bed, just in case it blows up But I'm very happy with how it works.

I'm using a piece of blue tape to figure out my fill line. But I suppose I could add even more water and try it out.

Anyway, I've been using this a few days so far so good. Although it's a little big, it should save me hundreds of trips to the kitchen for a rinse and refill, over the years. Over time I'll get an idea of my cleaning schedule.

Zombie thread, but the problem remains.
Mouth breathing causes the problem--wisest to eliminate the CAUSE.
Failing that, the easiest solution is to have TWO TANKS.
Slip the empty one out--snap the full one in--it takes mere seconds,
and need not hog space on the nightstand.
Not checking for mold a week at a time--I am HORRIFIED!

kalvinjuice wrote: ↑

Sat Mar 26, 2022 2:16 am

. But if you have trouble with the capacity of the 10, wait till you try an 11.

And yet, they hold the same 380ml of water.

chunkyfrog wrote: ↑

Sat Mar 26, 2022 8:51 am

Zombie thread, but the problem remains.
Mouth breathing causes the problem--wisest to eliminate the CAUSE.
Failing that, the easiest solution is to have TWO TANKS.
Slip the empty one out--snap the full one in--it takes mere seconds,
and need not hog space on the nightstand.
Not checking for mold a week at a time--I am HORRIFIED!

@chunkyfrog - old post but still quite relevant. Mouth breathing is NOT the root of the problem (for me anyways) - absolutely agree it COULD be, but in my case using I'm a mouth taper and CPAP user of 15 or so years; I'm highly confident its not mouth breathing causing my problem. Living in the Northeast the humidity and temperature vary wildly, and at times if I am able to 'sleep in' I was able to run out of water...no question.

This fix is still working perfectly for me. And others reviewing this should know that this is an option still, and likely for both for the Airsense 10 or 11 (the 11 has the same size tank, though I haven't modified one yet).

hmm, I didn't know the two tanks are the same size. I do go through water faster somehow then, I guess. And I've since decided to up the humidity and temp over the auto setting.

I didn't notice how old the thread was. I just Googled bigger AirSense tank and glad I found it.

Or you could try this ...
https://www.cpaptalk.com/viewtopic.php? ... r#p1406082

SleepGeek wrote: ↑

Sun Mar 27, 2022 2:29 pm

Or you could try this ...
https://www.cpaptalk.com/viewtopic.php? ... r#p1406082

I think you're referring to the HC150 and HC300 units...but I don't think they support the heated hose to prevent rainout, do they?

jdm5 wrote: ↑

Sun Mar 27, 2022 3:37 pm

I don't think they support the heated hose to prevent rainout, do they?

No it doesn't. So you'd have to get creative or use an old school heated hose. Or do like I do and go with the passover.
NO rainout with passover

Do you have a cover for the humidifier expansion tank? Seems like dirt/lint will get into it.