Humidifier heater issue

[terp1984]

I got my first ResMed AirCurve 10 ASV in April, 2022.  It worked fine for about seven months and then around once every five nights or so, the humidifier heater would not turn on.  I took it back to my local DME provider and they swapped it with one a few weeks old.  That one worked fine for about 13 months and it too had the same problem:  every few nights the humidifier heater would not turn on.  Since it was still under warranty, my DME provider sent it to ResMed for repair.  They gave me a loaner that was about a month old.  After a few weeks, it too had the same problem.  Next, my DME provider swapped the loaner with a brand new machine.  I confirmed it was new when I noted zero run hours.
 
I received that new machine on 4/15/24.  The humidifier heater did not turn on for the following dates:  4/21, 4/26 and 5/1.  I can always tell when this happens because when I wake up in the morning, my throat is dry.
 
I received my first ResMed S9 in November, 2011.  After about two months, the humidifier heater stopped working.  They replaced the H5i Heated Humidifier with a new one, but that did not solve the problem, so they replaced the S9 and that did solve the problem.  That machine worked fine for almost two years.  How much longer it would have lasted, I don’t know, because it was replaced with my first S9 VPAP Adapt.  That machine worked fine for about four years and then had the same problem.  Since it was less than five years old, my insurance refused to pay for a new one and since it was out of warranty, I bought a new VPAP Adapt out of pocket.  It worked fine for almost four years and it too, had the same problem.  This time, I foolishly purchased a new H5i Heated Humidifier and of course, that did not solve the problem.
 
I otherwise really liked the S9 and had hoped to keep using it since I had lots of extra accessories unique to that machine.  That is when I went through my insurance to acquire the AirCurve 10 ASV.
 
This is absolutely amazing!  I’ve used eight different ResMed CPAP machines over a 12-plus years period and seven of them had the same problem (the only one that did not experience this problem was in use for less than two years).  ResMed has to be aware of this and I strongly suspect they have no clue why it happens.  It also appears that the AirCurve 10 is worse than the S9.
 
Has anyone else had a similar experience?

[Phaleronic]

I've seen this happen to people over on reddit sleepapnea forum using the AS10. I personally used a new AS10 ForHer model for four months and it didn't ever have this issue, I sold it after that four months so I'm not sure if it developed the issue down the road...

[srlevine1]

Just some random thoughts...

Since this failure occurred on several machines, could it be that a unique combination of settings and ambient conditions actually turned the heater off? This happened to me, pre-forum when I didn't know how to manage my temperature/humidity settings properly.

Perhaps it might be beneficial to track settings and ambient conditions to see if they correlate with heater "malfunction."

Are you using ozone-cleaning or other cleaning methods that may impact the temperature sensor?

According to ResMed, "The temperature sensor located at the mask end of the ClimateLineAir heated air tubing enables the system to automatically control the temperature of the air delivered to the patient."

"The humidifier and ClimateLineAir heated air tubing are controlled by the Climate Control algorithm to deliver constant humidity and temperature outputs. The system adjusts automatically to changes
in:
 ambient room temperature and humidity values
 flow due to pressure changes
 flow due to mask or mouth leak."

One of my friends did experience an issue with the heater control plate due to corrosion from a high-humidity/salt-water environment.

-- Best of luck resolving the issue.

[terp1984]

Those are interesting thoughts and completely reasonable.  The first time I reported the problem to my local DME provider, they insisted it could be corrected by lowering the humidity level, which they did.  That did not solve the problem.
 
I believe my experiences are such that those possibilities you listed are not applicable.
 
All of my settings have been the same for more than five years.  The fact that one of the AirCurve machines functioned flawlessly for about 13 months (more than a full calendar year) would indicate that any environmental scenario had already been encountered before the problem began.  None of the incidents were one-off scenarios.  In other words, once the problem occurred, it continued to occur, albeit somewhat randomly.  Two different S9 machines functioned flawlessly for about four years each (one of which was in Virginia for about two years and all the rest were in South Carolina).
 
When the heater stays on, I wake up with my throat feeling comfortable.  When I wake up with a dry throat, I immediately sense the problem which is confirmed when I remove the water chamber and observe the metal plate is cold.
 
I use five different hoses.  In other words, while one is in use, the other four are hanging up to dry.  When the problem occurs, there is no pattern.  If it were due to a defective senser at the end of the hose, then it would be every fifth day.
 
I use no cleaning methods.  I avoid the need to clean the hoses by the procedure just indicated.  I cover the CPAP with a cloth to keep the dust off during the day.  I change the filter once a month.  One of my S9 machines is over 10 years old.  It looks just as clean on the inside as the day I received it.  I never leave the water chamber in the unit while not is use.  I use three different water chambers.  In other words, while one is in use, the other two are sitting out, covered with a cloth, drying out.
 
I use no cleaning methods except to occasionally wipe the dust off the exterior.  The fact that the new AirCurve had the problem after just six nights would indicate it is not due to any corrosion.

[srlevine1]

Looks like you covered everything. Now it’s down to a potential ResMed design/quality issue or you are “that guy” dinged by the fickle finger of fate. Best wishes on the quest for a solution.

[terp1984]

I believe srlevine1 hit the nail on the head (perhaps without even realizing it) when he made this statement:  "The temperature sensor located at the mask end of the ClimateLineAir heated air tubing enables the system to automatically control the temperature of the air delivered to the patient."

After posting my last reply, I went back and carefully analyzed my notes.  On March 19, the day I received my first loaner AirCurve, I reported to my local DME provider that the humidifier heater did not work on 3/3, 3/8 and 3/13/2024.  I was anticipating to report this apparent pattern, but it worked fine on 3/18 (at that time, I figured if there were a pattern, the heater would have failed on the 18th).  That loaner failed on 3/27 and 4/1 (why it worked fine for eight nights beginning on 3/19 is a bit puzzling).  The first day of my road trip was 4/5 and I returned on 4/14 (I use my old S9 VPAP Adapt when traveling).  Knowing that the last hose I used at home was unused for 10 days, I reused it that night.

As indicated in my original thread, the new AirCurve failed on 4/21, 4/26 and 5/1.  Why it was fine for six nights beginning on 4/15 is a bit puzzling.  Be that as it may, I have data associated with three different AirCurve machines with the heater failing every fifth day two to three times in a row.  Wow, that is exactly the prediction I made in my previous reply regarding what would happen if a sensor in one of the five heated air tubing lines was defective (this thought was driven by srlevine1’s comment – thanks man).  I was thrown off by the duration of nights when all was fine.  But the fact of the matter is, when it did fail, it failed more than once, and in each case, every fifth day.  Statistically speaking, this is unlikely to be a coincidence.

Bottom line:  I believe I have been remiss in my bad-mouthing ResMed (at least, partially anyway).  It appears that, at least in the case of these three AirCurve machines, the problem is actually a defective sensor in one of the hoses.

Unfortunately, at this time, I am unable to conclusively confirm that since I have stopped using the AirCurve and went back to using only my old S9 VPAP Adapt as of May 2 (see the unrelated problem in my other thread,  “Algorithm change in the ResMed AirCurve 10 ASV” for further explanation).

[srlevine1]

I am glad you now have a working hypothesis to test. BTW, you show you still use Sleepyhead in your profile, and I would suggest you upgrade to the more current OSCAR. Best. — Steve