Humidifiers not safe - seriously?

[sdb7802]

I'll talk about the two modern machines I own and have taken apart and examined pretty thoroughly: the A10 Autoset and the DreamStation Auto.

Both machines are rated IP22. This means a production sample has passed a water dripping test where a small stream of water is directed on the top of the machine for 10 minutes with the machine angled at 15 degrees without becoming damaged or unsafe. Not submerged, sprayed, splashed, or sitting in standing water. This is a typical minimum requirement for an electrical product designed for indoor use.

None of the pc boards in either machine appear to be coated (other than soldermask, etc.) or waterproof. The boards and the components are fairly well electrically insulated and physically isolated from the moist airsteam inside the blower housing. The pressure and flow sensors (and a humidity/temp sensor in the DS) are angled to drain any water back down into the housing. You would expect surface tension to hold a small amount of water in the sensor chambers, but I suspect that doesn't matter.

Both machines use 3-phase brushless pm motors, so no brush arcing. In the A10, the insulated motor windings are exposed to the air in the blower housing. In the DS, the motor looks to be sealed and isolated from the impeller. Both probably have sealed bearings or bushings. Electrically speaking, the blowers can probably tolerate a fair amount of water.

Since an intact and functional blower housing assembly is airtight, except for the inlet and outlet, dumping water into it from the water tank will probably not wet the pc board. I am concerned about physical damage to the spinning impeller if a substantial amount of water hits it. Also, impeller startup may be difficult with a water load. The motor control circuit may handle the overload without problems. So if you get water in the blower, drain it and let it dry some.

Obviously, if you wet down a powered pc board it's probably going to fail. If you wet down an unpowered board, you can try drying it off with a warm hair dryer. Water purity and the moisture sensitivity of the components will probably determine if it powers up successfully.

The humidifier heating plates on both models have seals and are probably safe from water damage. I haven't tested this.

The power entry module, on both models, is located on the lower part of the plastic case. It consists of a jack, small pc board, and some wires that lead to the main board. The A10 jack receives 24 volts dc and the DS receives 12 volts dc from their double-insulated power supplies. The position of the jacks makes them vulnerable to pooled or standing water.

The thread mentioned by Frank and started by Possum was a case where Possum's A10 power plug and jack were exposed to standing water. The plastic parts inside the plug melted and the machine quit working. I suspect the 24 volts (4 amp capable) boiled the water and melted the plastic. Not really sure of the source of the water or its purity.

It stands to reason, if you are using an electrical device and it's got water in it, you need to pay attention to spills and periodically inspect it for leaks. Hopefully, I've identified some potential problem areas.

I know most of this is obvious. It's just my $0.02.

[FrankNichols]

I'll talk about the two modern machines I own and have taken apart and examined pretty thoroughly: the A10 Autoset and the DreamStation Auto.

Both machines are rated IP22. This means a production sample has passed a water dripping test where a small stream of water is directed on the top of the machine for 10 minutes with the machine angled at 15 degrees without becoming damaged or unsafe. Not submerged, sprayed, splashed, or sitting in standing water. This is a typical minimum requirement for an electrical product designed for indoor use.

None of the pc boards in either machine appear to be coated (other than soldermask, etc.) or waterproof. The boards and the components are fairly well electrically insulated and physically isolated from the moist airsteam inside the blower housing. The pressure and flow sensors (and a humidity/temp sensor in the DS) are angled to drain any water back down into the housing. You would expect surface tension to hold a small amount of water in the sensor chambers, but I suspect that doesn't matter.

Both machines use 3-phase brushless pm motors, so no brush arcing. In the A10, the insulated motor windings are exposed to the air in the blower housing. In the DS, the motor looks to be sealed and isolated from the impeller. Both probably have sealed bearings or bushings. Electrically speaking, the blowers can probably tolerate a fair amount of water.

Since an intact and functional blower housing assembly is airtight, except for the inlet and outlet, dumping water into it from the water tank will probably not wet the pc board. I am concerned about physical damage to the spinning impeller if a substantial amount of water hits it. Also, impeller startup may be difficult with a water load. The motor control circuit may handle the overload without problems. So if you get water in the blower, drain it and let it dry some.

Obviously, if you wet down a powered pc board it's probably going to fail. If you wet down an unpowered board, you can try drying it off with a warm hair dryer. Water purity and the moisture sensitivity of the components will probably determine if it powers up successfully.

The humidifier heating plates on both models have seals and are probably safe from water damage. I haven't tested this.

The power entry module, on both models, is located on the lower part of the plastic case. It consists of a jack, small pc board, and some wires that lead to the main board. The A10 jack receives 24 volts dc and the DS receives 12 volts dc from their double-insulated power supplies. The position of the jacks makes them vulnerable to pooled or standing water.

The thread mentioned by Frank and started by Possum was a case where Possum's A10 power plug and jack were exposed to standing water. The plastic parts inside the plug melted and the machine quit working. I suspect the 24 volts (4 amp capable) boiled the water and melted the plastic. Not really sure of the source of the water or its purity.

It stands to reason, if you are using an electrical device and it's got water in it, you need to pay attention to spills and periodically inspect it for leaks. Hopefully, I've identified some potential problem areas.

I know most of this is obvious. It's just my $0.02.

Thank you very much, I appreciate the information.

[archangle]

You guys give them too much credit for the power brick. It is a bug - not a feature. Used to be, they put the power converter inside the unit. That was a good thing because bricks are just laziness on the part of manufacturers. The reduce the perceived foot print (they don't really because you still have to have one and that adds a separate footprint to the tabletop or somewhere else), and make it easier to assemble the unit because they don't have to physically put that power supply in the unit. But in the end, it is the consumer that has to deal with two separate boxes.

I disagree. There are several advantages to the external power brick. It makes it easier to handle the heat. It makes it safer. It means that you can replace the brick instead of the whole machine if the power supply fails, and power supplies are historically a high failure rate subassembly. It does make the part that goes on your table smaller and lighter.

It does have the disadvantage of there being another part to mess with, but it's not entirely a dumb idea.

[archangle]

If you spill the water and ruin your CPAP, the manufacturers make extra profit. It would also slightly increase the cost.

It wouldn't be hard to make the blower unit spill proof. Separate the electronics from the air path such that water going back from the humidifier wouldn't get into the electronics. You wouldn't even have to hermetically seal the electronics, or make them waterproof, but even that isn't that expensive. You'd need to make the motor water safe, by a barrier between the airflow and the motor, or making the motor waterproof. Waterproof bearings are no problem.

The sensors in the airflow are another problem. The pressure, air flow, and humidity sensors could be made reasonably water resistant without too much difficulty.

All of that would cost a little, but not much in terms of the cost vs. benefits it gives to the customer.

Another point, a number of people have reported turning over their machines and ruining them with the water. I'm guessing that about 10% of them kill the machine when it happens.

[OMyMyOHellYes]

It would be so simple if you guys just quit using humidification .......

[FrankNichols]

If you spill the water and ruin your CPAP, the manufacturers make extra profit. It would also slightly increase the cost.

It wouldn't be hard to make the blower unit spill proof. Separate the electronics from the air path such that water going back from the humidifier wouldn't get into the electronics. You wouldn't even have to hermetically seal the electronics, or make them waterproof, but even that isn't that expensive. You'd need to make the motor water safe, by a barrier between the airflow and the motor, or making the motor waterproof. Waterproof bearings are no problem.

The sensors in the airflow are another problem. The pressure, air flow, and humidity sensors could be made reasonably water resistant without too much difficulty.

All of that would cost a little, but not much in terms of the cost vs. benefits it gives to the customer.

Another point, a number of people have reported turning over their machines and ruining them with the water. I'm guessing that about 10% of them kill the machine when it happens.

Ah, a man after my own heart

[OMyMyOHellYes]

Ah, a man after my own heart

How much do you think the company could get for it?

[FrankNichols]

Ah, a man after my own heart

How much do you think the company could get for it?

My heart? Probably not much - it's been pumping now for over 60 years

I just got back from my Cardiologist for the followup to my latest echocardiogram and he says it's still running on all 8 cylinders - ie. excellent, which just made my day at 66

[Mosquitobait]

I've pulled my machine to the floor 4 times so far. 3 times were not at home. On the Airsense, my empirical evidence indicates that the humidifer hits the floor first, so any water spillage is AWAY from the machine.

I'm thinking of buying a Hose Buddy.

[palerider]

it's still running on all 8 cylinders -

good thing you're not supposed to have a v12