Concerns with new BiPAP purchase

Guest · Post by **Guest** » Wed Nov 22, 2006 5:47 am

Good News first: I finally got my new Remstar BiPAP Auto!!!!
I bought the "classic tank". I opened it, feeling like it was a Christmas present.

But... some issues have me concerned. If you move the unit gently, (tilting it from one side to the other) there is a 'thunk' sound like something is shifting inside. That same 'thunk' sound occurs whenever the start button is pressed. This is not normal right? It seems to work ok, and there are no error messages, although I've only used it for 3 hours. Otherwise it is very quiet!

I inspected the box it was shipped in, and there were no obvious signs of any impact damage caused by UPS. The humidifier tank might have a slight leak around the seal, but I have swapped the metal base part with one from my rental unit, and I'll test it again tonight.

I don't mind buying another tank locally anyway. It is the thought that this noise might mean my BiPAP may develop problems, later on, that is raising my already high blood pressure. I also picked up my fathers ashes today, so I am a bit down at the moment. Sometimes I have to give myself a strong mental kick in the backside; as a reminder of how lucky I am, and that others are far worse off than me.

Anyway... I thought I'd ask for your opinions / experience? I could host a short video/audio clip if that would help?

sinkem · Post by **sinkem** » Wed Nov 22, 2006 4:25 pm

The "thunk" happens every time I turn on mine. I passed 1000 hours last week and its going strong. It seems to be a very good machine.

Moogy · Post by **Moogy** » Thu Nov 23, 2006 4:35 pm

My unit makes a very quiet thunk if I move it as you describe. (I had never noticed this before.) It sometimes makes a similar sound when I turn the unit on, but not every time. It is a quiet noise and it has never caused a problem for me.

Moogy

elliejose · Post by **elliejose** » Thu Nov 23, 2006 6:36 pm

I have bipap auto M series. It also thunks when it starts.

offlineon · Post by **offlineon** » Thu Nov 23, 2006 8:56 pm

Hi,

thanks for your replies. Cpap.com replied to my query to say that it is normal. For some reason this topic was posted twice.

For a more detailed explanation, please see DME Daddy's reply in the original post here:

viewtopic.php?t=15290&highlight=concerns

dsm · Post by **dsm** » Fri Nov 24, 2006 12:11 am

Ahhha!

So the Bipap Auto is not the same blower as the Remstar Auto

I had been guessing that it was but that tell-tale thunk is an 'air solenoid' - they are in all the conventional BiPaps. I thought that in order to make the Auto Bipap they had switched to using a variable speed blower but I was wrong.

I purchased one of these machines but had it delivered to a friend who has a Remstar but who hasn't yet tried the Bipap Auto out.

Naturally I will disassemble it as soon as I get my hands on it & will post the appropriate photos but am pretty sure I know what it will look like now.

Thanks for that giveaway clue.

DSM

PS the air-solenoid is a device somewhat like the cone in a loud-speaker in the way it works. There is a fixed magnet and a moving coil-magnet. When no power is applied the moving coil part 'floats' thus the thunk, thunk as you tilt the machine. When power is turned on, the solenoid is activated & the moving coil part becomes magnetic and 'locks' to a particular position in relation to the fixed magnet - this allows the solenoid to pass a particular pressure of air. The excess air is recirculated back into the blower intake.

As the pressure need changes, the machine adjusts the magnetic field of the coil part of the solenoid and it moves back or forward adjusting the airflow as needed.

Here is a photo of the 'air-solenoid' as is in a Bipap Pro 2 ...
http://www.internetage.com/cpapinfo/rem ... age17.html

Quite a clever set up and one that works very effectively.

The Remstar Auto on the other hand, changes the speed of the blower to adjust the air pressure.

DSM

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CPAPopedia Keywords Contained In This Post (Click For Definition): bipap, Power, auto

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CPAPopedia Keywords Contained In This Post (Click For Definition): bipap, Power, auto

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CPAPopedia Keywords Contained In This Post (Click For Definition): bipap, Power, auto

Moogy · Post by **Moogy** » Fri Nov 24, 2006 11:35 am

dsm wrote: Naturally I will dissasemble it as soon as I get my hands on it & will post the appropriate photos but am pretty sure I know what it will look like now.

DSM, when you were a little tyke, I bet you drove your mother CRAZY disassembling all her appliances! I had a boy like that (now grown), and I started buying him old appliances just so he could take them apart.

I can't wait to see the pictures of the insides of the machine!

Moogy

dsm · Post by **dsm** » Fri Nov 24, 2006 3:50 pm

Moogy wrote:
dsm wrote: Naturally I will dissasemble it as soon as I get my hands on it & will post the appropriate photos but am pretty sure I know what it will look like now.

DSM, when you were a little tyke, I bet you drove your mother CRAZY disassembling all her appliances! I had a boy like that (now grown), and I started buying him old appliances just so he could take them apart.

I can't wait to see the pictures of the insides of the machine!

Moogy

Moogy yup but the story goes like this (according to my mother)

When I was 6 Mother says she took me to a psych to try to find out why I kept 'breaking' my expensive clock-work wind up toys (I grew up in the era before battery toys existed )

She says that the psych asked to spend some time with me with some of these toys - then after an hour or so, he came to her and said, "he isn't breaking them, he is taking them apart to find out how they work,".

After working in electronics for a while, self became an IBM mainframe engineer. Had lots of fun pulling mainframes apart when they stopped working - later became a software engineer & had tons of fun pulling software apart a) when it wasn't working & b) to see how it worked anyway.
Now my guess is that James Skinner has a similar story to tell

DSM

offlineon · Post by **offlineon** » Fri Nov 24, 2006 8:42 pm

dsm wrote:
Here is a photo of the 'air-solenoid' as is in a Bipap Pro 2 ...
http://www.internetage.com/cpapinfo/rem ... age17.html

Yery interesting! Is that a standard 3 Volt lithium battery on the pcb near what looks the beeper?

dsm · Post by **dsm** » Sat Nov 25, 2006 9:20 pm

offlineon,

Yes it is a 3v battery but has tabs on it and can't be removed. I seem to recall a discussion here some time back where someone said that if the battery fails the machine has to be returned to the factory or service centre.

As you can see I replaced the rusted bearings in the blower motor (water was left in the water chamber & the machine was packed away into its bag). Not good .

This machine has set itself to 1988 & nothing I did would reset the time. Local Respironics agent had a look at it & said it needed a new motherboard ($US1,000). I prefer to keep it to experiment with. I only paid $100 for it complete with H/H so am not at all concerned. The motor does have a harmonic whine as I haven't got the gear to dynamically balance the rotor & I did have a minor mishap with the torroid (magnet) where it fell on the floor & a chip of the magnetic material broke off & added to the imbalance.
I did use it for a night but the noise was a bit irritating but before I replaced the bearings it was a horrible noise

DSM