Help! My machine quit working.

[surferdude2]

BTW, for the air tube in the water vessel to be accurate, you should use a tube connected to the O2 port on the mask. If you use the main air flow tube with nothing connected, you will not get an accurate reading since the fan is not handling the proper amount of air that it is rated at and will tend to give lower pressure reading under those conditions.

[Doc J]

If you have not reset your machine yet I would. Unplug power from the back of machine for a minute an plug back in. Any electronic equipment can get a glitch and that may reset. Beyond that ck what everyone else is suggesting and or call the company and they should be able to help confirm the problem and have a solution. That's why I have a back up machine but I don't use Vpap which is een more expensive.

[retired_guy]

I have been using CPAP fora year and a half, so I do know how the ramp pressure feels. But your test is fabulous! I will try that this evening, for sure and let you know what happens. Thank you so much.

Kate

Also, please disconnect tube from mouth before placing under water.

[Kate]

I did Sleepsters test and with ramp time off, the pressure was 4. I then turned the pressure way up to 14 or 15 and the pressure was still 4.

Now I will give Payton's test a try. I have my fingers crossed but I'm not hopeful because I had not changed any of the settings before my pressure went bad.

But thank you to all for such really wonderful ideas.

---

Tried Doc's test....nope.

[Kate]

My back-up machine is at home. I'm on vacation. But I may get a travel machine and l lug both around when I travel. Bah, humbug!

Kate

[retired_guy]

You aren't vacationing in Telluride Colorado by any chance are you?

[PaytonA]

BTW, for the air tube in the water vessel to be accurate, you should use a tube connected to the O2 port on the mask. If you use the main air flow tube with nothing connected, you will not get an accurate reading since the fan is not handling the proper amount of air that it is rated at and will tend to give lower pressure reading under those conditions.

I do not understand why you can not get a good reading from the main air flow tube. Without the mask on the tube, starting the machine will give you way more than normal air flow but as you move the end of the tube down into the water you will get some back pressure that will make it more like normal use. I guess it really should not matter since we are concerned about pressure not flow.

Best Regards,

PaytonA

[surferdude2]

I do not understand why you can not get a good reading from the main air flow tube. Without the mask on the tube, starting the machine will give you way more than normal air flow but as you move the end of the tube down into the water you will get some back pressure that will make it more like normal use. I guess it really should not matter since we are concerned about pressure not flow.

Best Regards,

PaytonA

That's what I thought Paytona but my empirical results didn't come out that way. Fans do strange things when they are starving for input and pushing against a blocked output. Their static pressure at the output must be measured at some given delivery rate as dictated by what is known in the trade as "Fan Laws". You can get a lot of very dry reading on that by Googling "fan laws". I will add that it is the type of reading that may well render your CPAP device unnecessary.

The test with the air supply line only yielded a reading of .8 X machine setting whereas the test with the mask on and a using a small tube attached to one of the O2 ports on it yielded the same reading that the machine was set at.

Since the machine's pressure sensor is inside the machine and the pressure we want to subject our face to is downstream considerably, it would seem to follow that the number registered on the machine's LED is arrived at arbitrarily and was arrived at by taking into consideration several pressure drop factors which are affected by flow rate, such as the line length and the mask type. That's borne out by the fact that you must use a different setting on the machine when you change mask types. Go figure.

All the best, surferdude2

[PaytonA]

I agree with you that the pressure displayed by the Resmed machine is a close approximation of the pressure inside the mask.It is arrived at by considering the pressure drops due to the machine, hose, and mask ergo the settings for mask type and hose length. With no mask on the end of the hose there is one less pressure drop than normal but when trying to get an order of magnitude answer on whether or not the machine is working I do not think it is a big deal. For absolute accuracy you are right.

Best Regards,

PaytonA

[surferdude2]

when trying to get an order of magnitude answer on whether or not the machine is working I do not think it is a big deal.
Best Regards,

PaytonA

I agree and I will add that I didn't intend to over analyze the simple test you presented but it all started when I used the full size supply tube as you suggested. In the process of getting the reading, I managed to blow a large quantity of water from the container and made quite a mess in my laboratory (spelled bedroom).

It occurred to me that a smaller tube would make smaller bubbles and not be so violent as to belch all that much water in the process. Not having any suitable hose reducing fittings handy I decided to use the mask since it had some small ports on it for O2 insertion (and a side benefit of protecting me from any further water bath of my face ) . Since the resulting pressure readings were much different than those obtained when doing the first test. After I dried off, I decided I should report them in case someone wanted a more accurate test to see if their machine was actually delivering as promised.

I hope I didn't confuse the OP since your test was sufficient for her purpose.

All the best, surferdude2