4Hi Humidifier tank Level question

Sorry, another Newbie question:
I was trying to figure out how my CPAP knows the humidifier tank is "low" or "empty". I had half a tank of water remaining, (for my 2nd night) and figured I didn't have to empty it and would just use it for 2 nights in a row. I woke up at 4:30 AM with my Yucatán nose and cold air, and realized my mistake. However, the tank still had about 1/3" of water in it. I looked but didn't see any sensors so don't know what shut the heater off. Anyone know how it determines what it uses to sense low water? (We tech guys have to know how everything works!)

Regardless, I won't make that mistake again!

RedBackFur wrote:I was trying to figure out how my CPAP knows the humidifier tank is "low" or "empty".

As far as I'm aware, it doesn't know.... however, I don't own an H4i, so you should wait and see if anyone who does own one has more information to share.

RedBackFur wrote:I woke up at 4:30 AM with my Yucatán nose and cold air...."

The role of a humidifier is NOT to heat the air flow, its just to put more moisture into it by mildy warming the water to accelerate release of water molecules into the air stream.

If you are experiencing cold air problems, you may need a heated hose to overcome them.

Cheers,

Bill

RedBackFur wrote:Sorry, another Newbie question:
I was trying to figure out how my CPAP knows the humidifier tank is "low" or "empty".

i've had the 4hi for about 3 months now and as far as i can see the S8 only powers the heater plate. there is no feedback to the S8 to tell it about the water level. so, it is very easy to run the tank dry, which i have also done more than once. i have to remind myself to check it every night.

The H4i does not sense low water - I happened to run dry tonight.

Because I was used to a manual humidifier, it took me a while to learn to get it to warm the water reliably.

You turn it on by pressing on the right button while the machine is in standby mode, and the machine responds by blinking the "Humidifier Warming", and blowing a gentle stream of air. The word exit appears above the right button. When the humidifier warms, the little point of light on it waxes and wanes, when it stops (off, or reached the right temperature) the light is on, stable.

When you turn the machine off, the humidifier turns off, automatically, and the machine blows gently for about an hour. It will stop this, if the humidifier is on. In standby mode when you see the word "warmup" above the right button, the humidifier is off.

The confusing part is when you go back to bed, half asleep and turn the machine on. The humidifier will not turn on automatically - it has be turned on manually -- and as far as I've seen, this has to be done before you start breathing into your mask (if you have auto on) or before you turn the machine on.

I haven't found out how to turn the humidifier on or off when the machine is in use.

O.

ozij wrote:You turn it on by pressing on the right button while the machine is in standby mode, and the machine responds by blinking the "Humidifier Warming", and blowing a gentle stream of air.

All that does is start the optional pre-use water warming mode. It does not effect the normal humidifer operation (see below) at all.

ozij wrote:The humidifier will not turn on automatically - it has be turned on......

If the humidifier is enabled in the settings on an Resmed flow generaor, it will turn on automatically when the flow generator starts, by whatever method.

Cheers,

Bill

Do you mean there is a setting that has the humidifier turn on automatically?
Would that be user menu, or clinical menu?
Thank you,
O.

The way I understand it, the humidifier will be heating the water when the temp control is off the 0 position, and when the blower is moving air.
It doesn't sense water level; it isn't interested (it comes from Sydney, and that would be a little too intellectual<sorry Bill, couldn't resist that. ) The heater plate is temperature controlled, so if the water runs dry it really doesn't matter, except that you get a dry throat.

Look at my post on cleaning humidifiers for some other thoughts

K

ozij wrote:Do you mean there is a setting that has the humidifier turn on automatically?
Would that be user menu, or clinical menu?
Thank you,
O.

I just got mine last week and my DME told me the humidifier turns on and off with the start / stop button.

ozij wrote:Do you mean there is a setting that has the humidifier turn on automatically?
Would that be user menu, or clinical menu?
Thank you,
O.

Funny, I thought there was a setting for the humidifier, but now I can't find it. If someone knows where this is, can you help ozij and me out? Thanks.

Thank you for all the complex responses for such a question. The air wasn't so cold as it was dry. My poor schnozola really has issues with dry air, and somehow the low water level caused some drying. However, please make note: There is an LED transmitter/receiver set on my Autoset II, and a reflector device on the 4Hi humidifier that communicate something to the APAP....so some feedback of sorts is getting between the 2 devices, if you take a look!

RedBackFur wrote:and a reflector device on the 4Hi humidifier that communicate something to the APAP

That simply allows the flow generator to know there is a Humidifier attached by reflecting light from a LED on the flow geneator body into a optical sensor on the flow generator body. It serves no other purpose.

Cheers,

Bill

ozij wrote:Do you mean there is a setting that has the humidifier turn on automatically?

There is a setting that is automatically sensed by an optical feedback loop between a LED/sensor in the flow generator and a reflector on the humidifier. If a humidifier is attached, the Settings display for humidifier on an S8 shows simply H3i (same display for both an H3i and an H4i) with no option to change anything.

If a humidifier is not attached, the Settings display for humidifier on an S8 shows something like HUMD: None or HUMD: Face Plate, and can be toggled between those two setting values.

So, if the S8 is showing H3i in the Settings menu, then it knows a humidifier is attached and it will turn it on automatically when the flow generator starts.

Cheers,

Bill

billbolton wrote:
So, if the S8 is showing H3i in the Settings menu, then it knows a humidifier is attached and it will turn it on automatically when the flow generator starts.

Cheers,

Bill

I guess in the first days my humidifier temp was too low for me to notice it turning on automatically and warming.

O.

billbolton wrote:

ozij wrote:Do you mean there is a setting that has the humidifier turn on automatically?

There is a setting that is automatically sensed by an optical feedback loop between a LED/sensor in the flow generator and a reflector on the humidifier. If a humidifier is attached, the Settings display for humidifier on an S8 shows simply H3i (same display for both an H3i and an H4i) with no option to change anything.

If a humidifier is not attached, the Settings display for humidifier on an S8 shows something like HUMD: None or HUMD: Face Plate, and can be toggled between those two setting values.

So, if the S8 is showing H3i in the Settings menu, then it knows a humidifier is attached and it will turn it on automatically when the flow generator starts.

Cheers,

Bill

Bill thank you so much for this info. I was seeing H3i on my display and thought I couldn't find the setting