Metal In Water Chamber Now Darker

I have a new S9 dishwasher safe heated water chamber. I've only put it in the dishwasher once before this time and had let it air dry with everything being fine with it.

Last night I repeated the process but then placed it in my Hurricane CPAP Equipment Dryer for 30 minutes to dry it. When it was done I was shocked to see that the metal inside the water chamber had turned from shiny to a few shades darker and dull!

I called the medical supply company that I purchased it from but they said that they didn't hear about this ever happening before?

I tried to contact SiestaMed, the company that makes The Hurricane Dryer but their phone number is disconnected!

I'm just wondering if it's okay to use the water chamber now that the metal inside of it has changed?

Ms. OwLMooN wrote:I have a new S9 dishwasher safe heated water chamber. I've only put it in the dishwasher once before this time and had let it air dry with everything being fine with it.

Last night I repeated the process but then placed it in my Hurricane CPAP Equipment Dryer for 30 minutes to dry it. When it was done I was shocked to see that the metal inside the water chamber had turned from shiny to a few shades darker and dull!

I called the medical supply company that I purchased it from but they said that they didn't hear about this ever happening before?

I tried to contact SiestaMed, the company that makes The Hurricane Dryer but their phone number is disconnected!

I'm just wondering if it's okay to use the water chamber now that the metal inside of it has changed?

Should be fine. Water vapor molecules are too small to carry anything out of the HH tank to you.

I believe it was determined from a discussion on the forum recently that the metal in the ResMed machines is stainless steel.

https://www.cpap.com/productpage/resmed ... #specs-tab


Den

.

Stainless steel shouldn't change in appearance from a trip through the dishwasher but aluminum does. Is the exterior of the plate darker/duller than the interior surface of the plate? If you rub on the plate surface with a paper towel, does the towel get a dark smear on it? If so, that suggests that your tank has a plate made of aluminum and not stainless steel.

Does your chamber look like this one?
https://www.cpap.com/productpage/resmed ... amber.html

If it IS stainless, the tarnish is perfectly harmless more than likely either some kind of cleaning agent residue, or an oxidative film.. probably from the excessive heat of the dryer along with moisture. It "Should" clean up with lemon juice.

If it is Aluminum.. what you have just created is Al3O2 or Aluminum Oxide.. Also perfectly harmless.. and will form whenever aluminum is in contact with water and high heat.

If it is still giving you trouble.. Can you post a picture so we can have a better idea as to the nature of the material?

Aluminum oxide is Al2O3. Aluminum's valence is +3, Oxygen -2. But the bowl is Type 316 stainless steel, not aluminum. I have one.

I suspect dishwashing detergent, which is highly alkaline, remained behind after the final rinse and oxidized the surface of the bowl in the steamy heat of the drying cycle. Dishwashing detergents are optimized for removal of fats. They aren't very gentle to metals. I agree with Zoowabi that what you're seeing is simply surface oxidation, and it should not concern you.

I have always washed my reservoir in the sink using liquid dishwashing detergent. I then turn the bowl upside down and let it air dry during the day. Just because the humidifier chamber is dishwasher-safe doesn't mean that's the best way to clean it. I'm especially concerned about the repeated heat/cool cycles on the plastic components. Plastics can't take very much expansion/contraction before they develop stress cracks and fall apart. So I recommend washing by hand in the sink.

Slartybartfast wrote:Aluminum oxide is Al2O3. Aluminum's valence is +3, Oxygen -2. But the bowl is Type 316 stainless steel, not aluminum. I have one.

I suspect dishwashing detergent, which is highly alkaline, remained behind after the final rinse and oxidized the surface of the bowl in the steamy heat of the drying cycle. Dishwashing detergents are optimized for removal of fats. They aren't very gentle to metals. I agree with Zoowabi that what you're seeing is simply surface oxidation, and it should not concern you.

I have always washed my reservoir in the sink using liquid dishwashing detergent. I then turn the bowl upside down and let it air dry during the day. Just because the humidifier chamber is dishwasher-safe doesn't mean that's the best way to clean it. I'm especially concerned about the repeated heat/cool cycles on the plastic components. Plastics can't take very much expansion/contraction before they develop stress cracks and fall apart. So I recommend washing by hand in the sink.

Slarty, you are right about the plastic parts being NOT dishwasher safe. That is what the manufacturers want you to do, put it in the dishwasher, that way they make more $$$$ by selling more humidifiers to stupid folks that don't "think". Yes, the metal parts are dishwasher safe but NOT the plastic seals. Folks you have been duped by unscrupulous advertising.... think before you do it. I have never put my humidifier in the dishwasher and never will .
Cheers
Nan

When the directions say "TOP RACK ONLY", you also turn off the heated dry cycle. PLEASE!
This may not be on every item that specifies top rack, but the dishwasher manual will.
I ALWAYS use the air dry mode, and crack the door open to vent moisture.
----Just to spare the stuff on the top rack.

I hadn't heard of a "Hurricane CPAP Drier" so I had to look it up.
https://www.cpap.com/productpage/mvap-h ... HwodHD4KqA

The metal in S9 dishwashable tanks is stainless steel. "Standard" S9 tanks now have aluminum. All A10 tanks have stainless.

Stainless is the "gold standard" in medical and food handling equipment. Stainless is "stainless" because a transparent oxide layer forms on the surface and prevents further oxidation on the surface. If this layer gets thicker, it will sometimes show a rainbow color like an oil slick. Does your tank look like that? Sometimes, it will look black.

This happens with stainless food handling and medical equipment. It looks bad to some people, but is harmless.

Vinegar MIGHT remove it.

ResMed says not to dishwash the water tub, but they also say it's safe to wash disassembled water tubs in the dishwasher. "Please note that the disassembled tub lid, plate and base may also be washed in a dishwasher on the delicate or glassware cycle (top shelf only)."

As for the plastic, I wash mine weekly in the dishwasher with really hot tap water, and using the "sanitize" cycle that heats the water even more. I've had no plastic problems with S9 cleanable and standard tanks, PRS1, M series, and Respironics Legacy water tanks.

I've dropped all of the above tanks into 100C water and only the newer version of S9 "standard" tanks have had problems. They partly melted and were ruined.

Remember, if you ruin a water tank, they're only $30-40 online. I recommend to get a spare tank as soon as your insurance will pay for a replacement or just buy one online.