(01-18-2013, 12:02 PM)cpap5127 Wrote: The chamber is filled to the 75% line and only when I decrease the water to 25% or lower does it not boil/bubble. Again this happens seconds after I turn on the unit. Also the bubbles are being produced at the metal heating area.
I always have kept the humidifier at level 4
Hi cpap5127, welcome to the forum!
Sounds like, beneath the water chamber, the metal heating plate on the humidifier needs cleaning, or the metal bottom of your water chamber needs cleaning or has gotten a dent or dimple (even if only slightly) so it no longer sits perfectly flat. Or, if there are mineral deposits building up on the metal floor of the water chamber, these can be dissolved by putting a weak (5%) or strong (50%) vinegar solution in the chamber and leaving it to soak/dissolve the deposits.
If the metal of the water chamber does not contact the heating plate evenly the water chamber will need to be replaced, or else the heat will be too concentrated at some places, which perhaps could lead to the bubbles and noise occurring so soon, while most of the water is still cool (since this starts within "seconds" of turning on the humidifier).
So cleaning the heating plate and cleaning or replacing the water chamber may quiet the humidifier.
Of course there is a chance a temperature sensor (if there is one) has started to malfunction, but I would first suspect one or more of the other things, since it seems to work OK if you put LESS water in the chamber, making the chamber lighter, perhaps reducing pressure between the heating plate and the bottom of the water chamber, perhaps leading to slower heating of the water (so less bubbles and sound). If there were to be a dangerous malfunction, you'd likely have bubbles and steam when even LESS water is used, (as long as at least some water is used).
Good luck in your sleuthing,