ResMed H5i Humidifier Failure Mode

[tangram]

The H5i humidifier is used with the ResMed S9 CPAP. When mine displayed a warning that the ClimateLine heated hose was faulty, I trusted the warning and discarded the hose. Actually, the H5i was the problem.

If yours seems to be acting squirrelly, inspect the electrical port on the back of the humidifier. This is the part under the rubber cover. The inside of the port is bright orange and it contains three pins.

The pins are spring loaded in order to remain firmly in touch with the metal contacts on the ClimateLine hose. On my unit, one of these pins had collapsed and recessed. In addition, the orange plastic insulator around the pin had deformed, apparently from melting. There was even some residue which could be charring.

It would appear that current flow through this pin had heated and deformed the plastic. Or maybe, mechanical stressing of the pin had caused it to collapse which contributed to overheating of the immediate area.

So the H5i needs repair. If you experience intermittent behavior with your H5i, examine this port. A flashlight shining on it will help.

[FastGriz]

What a coincidence, I had exactly the same failure yesterday. I too ordered a hose only to find that wasn't the problem.

To get it working until a replacement arrives, I first tried pushing the pogo pin further in trying to get it to spring back out. DON'T DO THAT, all I accomplished was to crush the spring past it's elastic limit. I got it going again by forcibly pulling the pin from it's tube, stretching the spring back out, then re-inserting the spring/pin and recrimping the pogo pin and spring into the tube...

If I hadn't crushed the spring, it could have been fixed by disassembling the H5i, removing the pin from the plastic housing and scraping away the deformed plastic that the pin was getting hung up on.

My fix is not going to last though as re-crimping the pogo pin into it's tube with a pair of pliers is less than ideal and it no longer moves freely. I ordered a new H5i because I dread trying to sleep without it.

With a little research, the pogo pin could be replaced, probably with one from MillMax https://www.mill-max.com/new_products/detail/97

[marvindj]

Same exact problem with middle pin. I can't seem to see an obvious way to disassemble to deal with the spring. How did you disassemble?

[Sir NoddinOff]

Hmmm. Three people with that problem within several months. And I thought only Phillips Respironics x50 series machines had melting humidifier connection problems. Crappy engineering abounds. It would be interesting to have someone with this problem take apart the blower case and check the main PC board's humidifier connector for melting... I wouldn't be surprised if it's there too.

[WindCpap]

I posted the electrical resistances for the Climateline Air tube a while ago. It is probably the same for the S9 tube although the pins may not be in the exact same positions. A quick resistance check can help diagnose problems like these in the future.

Left Pin: Temperature Sensor
Middle Pin: Common (ground)
Right Pin: Heater Connection

Left to Middle is about 12 kOhm at about 70 degrees F. I don't know the exact transducer model, but looking up standard transducers, this will be about 20 kOhm at 50 degrees F,8 kOhm at 86 degrees F, 10 KOhm at 77 degrees F and 5 kOhm at 100 degrees F. If the values match approximately here, then the the temperature sensor and wires are good.

Right to Middle is 10 Ohm. This will also vary with temperature a little, but it is unlikely to vary much.