Humidifier heating element heats up when water runs out

[dh37]

I have a ResMed Airsense 11.

Occasionally the water in the humidifier basin runs out. AFAICT there's no sensor in the machine to turn the heating element off when that happens. Is that true? If so, is that liable to damage the entire machine? Or at most just the plastic basin (which can be replaced)?

I know this could be prevented by making sure it has enough water, but at least during the current season (I live in MA) that means refilling it at least every other night, and possibly every night. I wasn't sure if that's normal.

[Julie]

Not sure what you're asking about being 'normal', but of course since the heat applies to the water in the tub, the tub will overheat (and stink) if water's used up - so don't let it go dry, or make sure to refill if it does.

[jlsmithseven]

I've had mine dry out two times in the last couple of months because I was either too tired/busy to remember to fill it. Each time it woke me up in the middle of the night with a terrible burning plastic smell. I've had to replace my hose/basin twice now because of it. No matter what I did to clean it the smell wouldn't go away. Hopefully on the next model they have something to turn it off, it seems like it should. Maybe we can recommend it.

[palerider]

I have a ResMed Airsense 11.

Occasionally the water in the humidifier basin runs out. AFAICT there's no sensor in the machine to turn the heating element off when that happens. Is that true? If so, is that liable to damage the entire machine? Or at most just the plastic basin (which can be replaced)?

I know this could be prevented by making sure it has enough water, but at least during the current season (I live in MA) that means refilling it at least every other night, and possibly every night. I wasn't sure if that's normal.

yes, it's true, and yes it's normal, many people fill their tanks every night, maybe most do.

[Conrad]

I don't know for sure but from an engineering standpoint it wouldn't make any sense to have the hot plate capable of reaching a temperature that could damage/melt/make stink the water reservoir. The designers would know that running out of water would be a common thing and the design would take that into consideration.

It seems to me, again, from an engineering standpoint, that if the water is set for a certain temperature, say 90 degrees, that would be the max temperature of the hot plate in this example. There HAS to be a thermostat to control the temperature of the hot plate, thus the water. It wouldn't make sense to have the hot plate heat up to a higher temperature than needed. Especially to a temperature that could damage any plastic.

I know that lots of folks have complained about the smell after running out of water, I've ran out and never smelled anything 'funny'.

[Pugsy]

I know that lots of folks have complained about the smell after running out of water, I've ran out and never smelled anything 'funny'.

You are a lucky one.

I have run out of water several times (I have to refill or top off each night and on occasion I forget) as far back as my first machine which was a Respironics M Series and it stinks to high heaven if I let the chamber go dry for very long.
The smell never lasted though...didn't seem to be a permanent odor. Gone the next night. Never had to trash the chamber because of the odor.

Don't know if the length of time the chamber is bone dry makes any difference or not. Perhaps that's a factor.

[dh37]

I don't know for sure but from an engineering standpoint it wouldn't make any sense to have the hot plate capable of reaching a temperature that could damage/melt/make stink the water reservoir. The designers would know that running out of water would be a common thing and the design would take that into consideration.

It seems to me, again, from an engineering standpoint, that if the water is set for a certain temperature, say 90 degrees, that would be the max temperature of the hot plate in this example. There HAS to be a thermostat to control the temperature of the hot plate, thus the water. It wouldn't make sense to have the hot plate heat up to a higher temperature than needed. Especially to a temperature that could damage any plastic.

I know that lots of folks have complained about the smell after running out of water, I've ran out and never smelled anything 'funny'.

Yes, from an engineering/design perspective it doesn't make any sense to me either. Happened once on my Airsense 10; in that case the smell either went away or could easily be fixed by getting a new basin.

[dh37]

Smell isn't going away after a few nights of this so I created a new thread about what to do: viewtopic.php?f=1&t=187489&p=1448727#p1448727