Noise

Can someone tell me where to find information about noise levels of c-pap machines? I'd like to be able to compare before I purchase.

Thanks, Terry

Here's a good previous thread you can click on about noise:

Which is the quietest cpap machine

There is a suggestion in there to go to each manufacturer's website and take a look at the specs for each machine to find the decibel rating. However, since the noise level can vary, even between 2 identical machines, it really just depends on the one you happen to get.

It's very tough to go by noise levels .. some machines are quiet but have a distinct whinning sound that will drill through your head. Fluctuation in tone is what really drives me nuts.
My orignal F&P HC234 was the loudest db wise, but it had a constant white noise sound that was very soothing.
RG and DSM nailed it .. it's luck of the draw .. all you can do is try them out.

This is an interesting issue as I believe I now may have an explanation as to why some Remstars provided thru DMEs may be noisier than others.

(What follows is my best guesstimate at what may have happened - at the end I will explain its relationship to all brands of xPAP noise).

Over the months there have been threads here alluding to Remstars failing and being sent back for repair & the repair center being inundated by the backlog. However some people here also have said they have had Remstars serviced & not had delays.

As Remstars go I regard them as among the Rolls Royces of xPAP machines. Very well designed, very well built. BUT, there is one factor beyond Respironics control that I think may give credence to the above story. This is the ability of owners to tip their Remstars up while attached to their loaded humidifiers and to get water in them that if it gets to the motors can and has in one of my machines, rusted the motor bearings).

We have had several people acknowledge they had got water in their machines & sent them for repair. I believe there was a problem with this occurring and that if there was any backlog of repairs that seems the most probable cause. They are really too well built for me to believe it was anything else.

I also believe we will see a new design in the way the humidifier connects to the blower and that this redesign will go a long way to reduce this type of damage. Cpap.com do sell a small valve for non Remstar units to help prevent similar problems with them. ALL xPAPs can be vulnerable to this condition.

So back to noisy machines.

The unit I obtained that had water damage was repairable & required the motor to be stripped down & two new bearings fitted BUT the new bearings are very noisy when the unit is 1st turned on but as it warms up the noise abates. Also several people here have commented that they had noisy Remstars that in time improved. There are people who had noise on a Remstar but we were able to pinpoint that they had not fitted the h/h to blower coupler properly & when that was corrected their noise went away.

Refurbished machines of any brand ...

I suspect (no evidence) that the bulk of refurbished machines are ones repaired as a result of internal water damage & that if one buys a used or refurbished machine *or* is given one by a cost cutting DME, that it may have had a new motor or new motor bearings & thus may appear noisier than another similar machine that hasn't had this problem.

As an aside. In an earlier linked to article I mentioned swapping a blower from an Elite to a Spirit & that the noise stayed with the xPAP not the blower.
I see 3 people later raised the issue of the baffling in the unit as the cause but because I missed their posts I didn't get to tell them that *no* it had nothing to do with baffling as the blower assembly in the Elite/Spirit contains a blower in a sub-assembly that also has the sound baffling.

I tried to make clear that the Auto drives the fan differently to the way the Elite CPAP drives its fan and that that was the cause of the increased 'apparent' noise. One unit whines the other hums.

The Remstar AUTO has substantial baffling around the motor. The Plus has none, the Pro I don't know.

Most modern xPAPs especially BiLevels and AUTOs, vary the speed of the motor to change pressure on the fly - xPAPs with BiFlex & EPR & AUTOs now all work this way. CPAPs will generally run at a fixed speed & don't vary motor speed as much as the other types do while in use.

The ultimate rock solid blower has to be the F&P HC201,221 23x etc:. I have blown as hard as I could down the air tube while they run, to see if I could slow the blower - nup, couldn't do it, and the noise did not seem to change the slightest in pitch, but I can do so on some other models (PB42x), Resmed S7 & S8.

CHOICE ..

You really need to try a few


Cheers

DSM

Some people turn on the heated humidifier and let it warm up the water before turning on the blower. I believe I even read this in one of the manuals that came with my unit. The mist created can find its way into the motor area unless the blower is on. However, when the Remstar Auto's blower is on with wide open hose or mask opening, the Auto detects that as a large leak and shuts down the blower. Therefore it is not wise to have your heated humidifier on unless the mask is on your face.

The newer Remstars have a little splash guard in the humidifier container to help prevent water getting into the motors by accident. Still I would always remove the humidifier container before moving or packing the APAP.

If you are still getting noise from the motor after both bearings are replaced I would think you may have end bell problems (end caps where the new bearings were likely installed). Usually bearings are replaced in pairs but some techs may not do this. This noise is another sign that a failure is a good possibility.

Edited to say:

However, when the Remstar Auto's blower is on with wide open hose or mask opening, the Auto detects that as a large leak and shuts down the blower. Therefore it is not wise to have your heated humidifier on unless the mask is on your face.

I rechecked this again by just leaving my unit run, no humidifier connected and it did continue to run without shutting down. Not sure what happened the night it did shut down with mask leaks.

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CPAPopedia Keywords Contained In This Post (Click For Definition): humidifier, hose, auto, APAP

Darth Vader Look wrote:Some people turn on the heated humidifier and let it warm up the water before turning on the blower. I believe I even read this in one of the manuals that came with my unit. The mist created can find its way into the motor area unless the blower is on. However, when the Remstar Auto's blower is on with wide open hose or mask opening, the Auto detects that as a large leak and shuts down the blower. Therefore it is not wise to have your heated humidifier on unless the mask is on your face.

The newer Remstars have a little splash guard in the humidifier container to help prevent water getting into the motors by accident. Still I would always remove the humidifier container before moving or packing the APAP.

If you are still getting noise from the motor after both bearings are replaced I would think you may have end bell problems (end caps where the new bearings were likely installed). Usually bearings are replaced in pairs but some techs may not do this. This noise is another sign that a failure is a good possibility.

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CPAPopedia Keywords Contained In This Post (Click For Definition): humidifier, hose, auto, APAP

Absolutely,

The Resmed S7 & S8 models when powered on but not blowing, push a very small flow of air out just for this purpose (to keep moistened air from both integrated & 3rd party H/H units from seeping back into the machine).

Re end bell cap - this motor had no end caps just the motor end plates so the bearings are a firm fit. New bearings do need bedding in. I believe the motors in new machines have been run in & noise tested before sealing the units up.

Also, something some people here in the past have not realised is that when water gets into the air exit hole, it doesn't flow into the electronics as the air plumbing is completely sealed inside all types & models of xPAPs.

All the water can do is seep into the ...

1) Exit hole air pressure tube - only on those machines that have a pressure sensor (except PB models where this small tube continues to the mask)

2) As for one, machines that have a pressure sensor will almost always also have the two tube flow sensor mechanism

3) Water can find its way through to the motor shaft & thus the bearings

If the water gets into the pressure sensor line the machine may sit on its lowest pressure & not move up

If water gets into the flow sensor lines it will give false leak readings and can (for BiLevels) cause the machine to stay on the Epap pressure

If water gets to the motor it can seep right inside the motor & although these modern brushless motors are so good they will run even with water in them, it will of course harm the bearings


This link shows a Remstar motor that had become half filled with water & had rusted the bearings. This unit had water in one of the two flow sensor lines & that caused it to stay on EPAP until cleaned out.

http://www.internetage.com/cpapinfo/rem ... index.html

The thing to do if one has let water get inside the air exit hole, is to tip the unit end on & drain as much out as possible as soon as possible, I personally would also put a reversed vacume cleaner into the air intake (filter removed) to blow air through (should do no harm at all), then after a few minutes would try to turn it on so its own motor will blow any remaining water / moisture out.

A gentle shake may also help.

Cheers

DSM