You are here: Rants, Rave, & Tips

Rants, Raves & Tips

CPAP Madness - Philips Respironics REMstar (Recall, Squealing, and Crappy Sleep)

Date: 10/4/2021 12:17:10 PM

DISCLAIMER -- a CPAP is an expensive piece of prescribed medical equipment.  I am in NO WAY advocating that you should do what I describe below.  Not only does working with electronics pose serious dangers, messing around with a piece of medical equipment is not a good idea, and I strongly advise against it.  Please consult with your doctor and/or your licensed CPAP dealer or repair service.  What follows is my personal experience, and I am NOT RECOMMENDING any specific course of action for others.

With the CPAP recall regarding their foam / chemical compound issue, my machine was squealing like a banshee, and I was not able to sleep for weeks -- it was time to take matters into my own hands. 

This blog post is a little off the path from business and software development, but I wanted to share my experience in case it helps anyone else out there.  A CPAP is a machine for those with Sleep Apnea.  I have Obstructive Sleep Apnea (OSA). 

The severity of OSA can vary between people, but essentially OSA is your body's airway collapsing on itself and you not being able to breathe while you sleep.  This leads to snoring, reduced oxygen levels, terrible sleep quality, and a slew of potentially serious health problems.  Before getting diagnosed and getting a machine, my sleep study revealed that my body was stopping breathing, on average, 60 times per hour.  It took a few weeks to get used to wearing a CPAP mask every night, but now that I'm 5yrs+ into using it, the CPAP has totally changed my quality of life -- really.

A few months ago, Philips announced a recall on many of their CPAP, BiPAP, and other breathing equipment.  There are countless news articles out there if you want the details, but high-level: there is sound proofing foam padding inside their machines that degrades overtime and was manufacturered with compounds that you don't want into your lungs.  Between the COVID supply chain issues, and the recall of some 400k breathing machines, it's almost impossible to get a new machine right now.  If you have a machine you need to check your model/serial # on Philips' recall site, read the warnings and talk to your doctor -- this recall is serious.

Coincidentially, the same time the recall was announced, I was considering replacing my CPAP because it was starting to seem a little tired.  It's a big decision because these things are so expensive.  The machines range from $600 to a few thousand, and the masks are hundreds of dollars themselves.

Labor day weekend, we went camping at the cabin.  Per usual, I brought my CPAP and it worked as expected all weekend.  Sunday night at home, I set up my CPAP on my nightstand, and attempted to use it, and it sounded like someone swinging a bag of cats into a wall.  It immediately woke up my wife, and we were both like "wtf"?!  Exhausted, I couldn't figure out what was wrong with it -- so off to the couch I went so my wife could get some sleep.  

After not sleeping well (basically choaking all night), I cleaned the machine, took apart all the user-servicable parts, and still it just kept squealing.  It sounded like the motor or maybe an air leak, but my mask and it's cushion were good.  The hose was good.  The humidifier tank seemed good.  At this point, it looked like I just needed to buy a new machine. !#@$!#$

I jumped on my favorite CPAP supplies site ( to buy a new machine.  Sadly, after digging through their site and talking with their customer service (always awesome people there!), I discovered because of COVID and the recall, there were no machines to purchase.  Philips had told the vendors/distributors that they expected some shipments in early September, but they never came, and Philips updating them with "we have no ETA".

This same "hope I can do something", "darn thing is still loud", "back to the couch/choaking" routine happened for a few more nights.

Eventually, I figured out if I lowered the prescribed pressure a bit, the noise would calm down slightly.  The problem is the proper (and doctor prescribed) pressure is what keeps your airways open while you're sleeping.  Eventually I found a middle ground of reduced pressure, putting the CPAP inside my nightstand, and a large box fan (to create white noise) that was just enough for me to get something resembling sleep, and for it to be reasonable for my poor wife to cope with.

This "in a drawer" solution continued to work for a couple weeks, but the reduced pressure was clearly having a giant impact on my quality of sleep and energy for the day.  I had enough, it was time for something drastic.

If you're a follower of my blog, you know that I dabble with electrical engineering, Arduino, and I was the kid taking apart his parents' VCR and computers.  It was time to do some research into how the CPAP works, and what's under the hood.

I found a few blogs and videos, and discovered that the guts of the REMstar are basically one circuit board, the motor, and some fancy plumbing with vibration and sound deadening. To get it a part, it's just a few screws on the bottom.  So, I decided I had had enough, and was going spelunking.

First, I removed the humidifer (which is a lever on the bottom side of the humidifer and it slides off).  The bottom of the machine has a few Torx screws, which I had drivers for.  The rotatory button pulls straight off with a little force, and then top of the machine comes off.  Then there's a screw that holds the circuit board in, and a few wire harnesses to unplug.

Next, to get the motor out, there's a little monkeying around.  First, take the left side panel off (it slides up/out).  Next, I loosened the screws on the motor assembly (it comes in half, top/bottom).  You need the motor assembly shell loose so you can wiggle out the air output tube** from the right side of the machine - this also removes the right-side panel.  Once those are out, you can undo the screws and you'll find 4 plastic tabs that are holding the top of the motor assembly into the body.  I slid in four credit cards to hold the tabs back, and pulled the motor assembly out.

The foam pad is just sitting there in the bottom of the unit.  It lifted out, seemingly not glued or anything, and straight into the trash went that headache.  Problem #1 solved.

Next was trying to figure out what the insane squealing noise was all about.  I carefully inspected the motor, impeller and circuit board for damage and wear, but everything looked okay.  Frustrated that I couldn't see the issue, I took a investigative break and decided to carefully clean each of the components with a damp, clean rag (except the circuit board which only got a little compressed air).  Behold - it was this cleaning that lead me to my squealing issue!

**Above, I mentioned the right-side air output tube.  This tube connects to the motor assembly with rubber gasket/bushing of sorts.  When I started cleaning this I discovered there was some of gunk on the rubber bushing.  I'm guessing it was probably just some dirt and sediment build up from the years of use.  It appears that the machine was designed so that the material difference of the rubber bushing and plastic tube would create enough friction between the two to create a tight seal that would hold back the operating pressure of the machine.  BUT with the bushing being dirty, it was not making a smooth seal.  In short, I started hoping that the squealing noise was this bushing flapping rapidly against the tube instead of sealing tightly against it.

I finished cleaning all the parts, and carefully reassembled the machine.  Of course, because of Murphy's Law, after my first reassembly, I realized I forgot to put the left-side panel back in place.  So I tore it down again, and replaced that panel. SMH.  Initially, I left the humidifer unattached so I could test just the machine itself.

The squealing was gone, the foam was out, and surprisingly the machine/air felt cleaner (probably from the 'gunk' removal and careful cleaning)!

I reattached the humidifer, tested again, and all was good.  Lastly, I returned the machine's pressure setting to my prescribed level (11 CMH20), and the machine hummed along without issue.

It's now been a couple weeks, and my CPAP seems good as new.

Couple updates and last thoughts:

  • My new machine is still on backorder.  I'm coming up on almost 30 days since the order was placed.  I talked with this morning and they do have a few "Mini" models back in stock, but they are still waiting for the regular size machines.  No ETA yet, but was assured, I'd get a shipping/tracking notice as soon as they are in.
  • If your curious how to changed the prescribed pressure on my machine... First, I can't stress enough, don't mess with your prescribed setting and your machine unless you completely understand and accept the risks -- this is not something you should causually play around with and I'm not advocating that you do so, and I recommend you do NOT change your setting.  But, if you want to know how that works.... There's a hidden menu on the REMstar that accessed by rotating to the "Settings" menu option, then pressing and holding both the rotatory button AND the ramp button at the same time for a couple seconds.  The machine will beep, the screen will refresh, and you'll enter the clinician's menu where you can adjust various settings including the prescribed pressure.  This button combo, I'd imagine, varies from model to model.
  • Removing the foam padding from the bottom of the unit didn't seem to have any noticable effect on the CPAP's sound level.  While many people have mentioned online that they haven't seen any foam particles in their filters/hoses/masks, it's important to realize it's not just the foam falling apart, it's the chemicals that the foam was produced with.  Again, get your machine replaced/repair via the recall, don't rely on just hacking the foam out of the machine yourself.  Additionally, while I do feel better that the big piece of foam is out of my REMstar, there's still the small foam input filter on the back of the machine.  I left that in place (as I don't want debris entering my REMstar), but I have no idea if that small foam filter is manufactured the same way the internal foam pad is.  None of this is a long term fix for me, as I'm still waiting for the new machine to ship.

I hope this rant has the oppportunity to help someone else out there, or at a minimum was interesting.  If you're a new CPAP user and hate it, give it time.  Also don't be afraid to try different mask types and talk to your doctor.  Stick with it, it gets better (and is emmensely worth it).

Sleep is like the golden chain that binds our health and body together.
-Thomas Dekker