AirSense 10 Humidifier badly discoloured after first use

[daytona]

I ran into the same problem with mine. It's the regular tub and I have only used distiller water. When I reported it to Resmed they blew me off and told me to talk with my DME which I did not have at the time. I have since replaced it and made sure to empty it every morning. Not sure if that has made a difference but it is much less discolored.

Also the discoloration always starts in the same place, back of the tub closest to the machine, in a small 1" rectangle... I wonder if the heating element gets hotter there?

[TangledHose]

Maybe try and convince ReMed or your supplier to give you a free Dish Washer safe tub and see what happens with it, if it does ok then you're all set ......maybe

[princessbelle]

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[dave21]

Thanks Guys, I can confirm night 2 there was no further damage done to the tub, looks about the same as the first night. I'm wondering whether when they adhere a metal coating or clean the meta whether its dipped in some kind of acid or chemical and maybe there were residues there that when heated up caused the fault, but agree it does look like it's more of a heating element problem. Obviously at 27C water doesn't boil, no where near that but there's very distinctive bubble marks from where water was sitting and looked like it was bubbling. It's possible that maybe it wasn't that noticeable out of the box and became more noticeable after use when the metal was heated, not sure. I definitely didn't see it though before use and I did check out every part thoroughly before first use including looking inside the tub and didn't notice anything.

Will await Resmed's decision on this, but I'll drop them an email and ask for a dishwasher tub replacement seeing that some of you haven't had a problem with that one and see if they'll do that, or it'll be maybe return the entire unit for inspection and get a replacement. Either way I don't mind providing it gets fixed. This definitely shouldn't happen after one night use.

[dave21]

Previously on the S9 I had the dishwasher safe tubs so maybe that's why I never saw a problem on the S9, but still if it's a manufacturing defect in the metal used, Resmed need to recall these or at least offer replacements if any are affected, but if it's the heater element inside the AirSense 10 that's at fault then that needs to be looked at further. Although unless that heater element is malfunctioning and heating up to say 80C or something ridiculous which I can't see it doing that, it really shouldn't affect the metal in that way.

[TangledHose]

Dave - I am curious about one thing in your case, can you take a flashlight and with the tub out of the machine take a close look at the heat plate itself and see what it looks like. Is there any corresponding discoloration from excessive heat on the heat plate? I'll check mine too, but I bet it's just a batch of crappy metal in the tubs themselves.

By the way I was looking at clinicians manual and there is a safety limit for the heat plate so it shouldn't ever exceed a certain heat, I'll look again and post that cut out heat limit.

[TangledHose]

The max heater plate temps are higher than I would have guessed!

Maximum heater plate: 154 F. (68 C.)

Cut-out: 166 F. (74 C.)

TOASTY.

[silver123]

I checked in with cpap.com last week after noticing the same discoloration in the same place. I have used distilled water since I got the unit in late August and clean the tank as suggested.

They checked with Resmed and this appears to be an identified problem. They are supposed to get back to me about this. I've taken the the unit off auto and knocked the temp down to 75 degrees.

[dave21]

Dave - I am curious about one thing in your case, can you take a flashlight and with the tub out of the machine take a close look at the heat plate itself and see what it looks like. Is there any corresponding discoloration from excessive heat on the heat plate? I'll check mine too, but I bet it's just a batch of crappy metal in the tubs themselves.

By the way I was looking at clinicians manual and there is a safety limit for the heat plate so it shouldn't ever exceed a certain heat, I'll look again and post that cut out heat limit.

I didn't think of checking that. I've just checked with a flashlight and there doesn't look like there's any discolouration or marks on the heater plate at all. I tried to take a photo but the flash keeps rebounding so all you see are the inlet/outlet circles reflected on the metal plate, but the metal heating plate does look fine in itself.

I checked in with cpap.com last week after noticing the same discoloration in the same place. I have used distilled water since I got the unit in late August and clean the tank as suggested.

They checked with Resmed and this appears to be an identified problem. They are supposed to get back to me about this. I've taken the the unit off auto and knocked the temp down to 75 degrees.

Thanks, that helps a lot, I'll go back to ResMed UK with this info. It definitely seems to be a problem with the main tubs that come with it. I've been trying to rack my brain (but it's 5 years ago) but I seem to recall something similar on the S9 with non-dishwasher safe tubs, at least something feels like Deja Vu to me on this. I've not experienced this before but I seem to recall some that had the S9 tub previously where you couldn't open and separate the top and bottom halves having problems, but my S9 shipped with the one that you could unclip and wash out thoroughly and never had problems with that or replacement tubs I purchased.

ResMed UK did say to continue using the tub and the Climate Control and it should be safe to do so, but you have to wonder with that amount of discolouration, did some chemical coating burn off the coated metal and are you inhaling it? Even if it's possible, I'm sure it's not enough to cause any kind of long term damage, but yeah I do wonder about stopping using the Climate Control feature.

[chunkyfrog]

I showed the images to DH, who was a welder and machinist before he retired.
His opinion: either very high heat, or extremely low grade stainless steel.
He also asked if the tank had boiled dry.

[TangledHose]

The heat cut out limit is well below water boiling temp and I think the OP said he did not run out of water in the tub......I think it's a batch of inferior metal in some of the standard tubs. They use better grade steel in the dishwasher safe tub......the standard tubs are probably made in China.

[dave21]

I showed the images to DH, who was a welder and machinist before he retired.
His opinion: either very high heat, or extremely low grade stainless steel.
He also asked if the tank had boiled dry.

I think I'd side more with inferior metal / coating applied. I started the evening fulling the tub to just under the full mark and had about half a tub of water left after 9 hours use, so it never ran dry. I would presume if it did run dry it would sense and cut out after a period of time, but if it doesn't I wouldn't think the heat generated would be hot enough to make marks on metal like that.

[dave21]

The heat cut out limit is well below water boiling temp and I think the OP said he did not run out of water in the tub......I think it's a batch of inferior metal in some of the standard tubs. They use better grade steel in the dishwasher safe tub......the standard tubs are probably made in China.

Yep I think you're right about the quality of metal used, dishwasher safe tubs need to be stronger, so that might be why, but still the metal used shouldn't be that inferior that after a single nights use it causes this sort of damage. I'd almost think it's aluminium with a metallic coating applied that discolours under heat or something along those lines. Definitely a quality control issue for ResMed, and it's not the first heated humidifier they've made, we're into at least 5 or 6 generations now of heated humidifiers and tubs.

[Demerit]

I've had several conversations with Resmed about this issue. It is inconsistent in when it is happening, some folks are using distilled water and seeing it but it is mainly occurring in those who are not using distilled water. It also has to do with something within the machines environment, but the "something" is still being determined.

[Greg Riddle]

Thats what is known as thermal spalling. It's a defect in the metal caused by a hotspot that formed when that part of the metal got much, much hotter than the surrounding metal. Somehow it heated unevenly and as a result it caused this thermal spalling. This is a good indication that either the heating element is faulty or it is distributing the heat very unevenly, Either way, Resmed needs to look into this further. Don't be surprised if they ask you to send it back to them and give you a free replacement. They'll probably want to dissect that one to find out what went wrong in the manufacturing process.

I agree and add that it could also be a warped metal plate or tub bottom. Either one could stop the two surfaces from making contact and cause a hot spot