02-20-2025, 09:26 AM
(This post was last modified: 02-20-2025, 09:43 AM by SluggerBaloney.
Edit Reason: typos
)
Sick and tired of your humidifier tank running empty during the night?
Sick and tired of your humidifier tank running empty during the night? Build yourself a self filling humidifier water tank!
Parts & Supplies needed:
DISCLAIMER/WARNINGS:
I have always had an issue with the humidifier tank running out of water in the middle of the night, causing a foul odor from the humidifier plate, and making my lips and mouth dry out as I slept. So I decided to build a self filling humidifier tank to solve the problem
PARTS NEEDED
First thing we need is a water pump. I went with this one: PlusRoc 12V DC Small Water Transfer Pump 1.3LPM Mini Self Priming Micro Pump with Food Grade Pipe and Power Adapter (https://www.amazon.com/gp/product/B0DB1T56HW/). $17.48 at the time of this writing
I like this pump specifically because it has a power supply with an independent switch on it, so you can kill the pump easily while testing. It is also quiet and will not wake me up when running. And it includes more than enough tubing needed for the project. And it's cheap.
Next, we are going to use a float switch to turn the pump on and off as needed. We need to use a float switch since distilled water is really bad at conducting electricity, so normal water detection boards and circuits won't work. We will need a NC (Normally Closed) float switch that fits inside our water tank and turn off the pump when the water is the appropriate level. After testing 4-5 different switches, this is the one I managed to make work: uxcell PP Float Switch for Water Pump Tank Liquid Water Level Sensor M12 2pcs (https://www.amazon.com/gp/product/B07DZ1J2GB/). $12.19 at the time of this writing.
STEP ONE: Modifying and attaching the Float Switch
Even as small as the float switch is, it is still to big to fit in the tank and turn off at the correct water level. You need to take a dremel/rotary tool with a cut off wheel, and trim the bottom of the plastic off the float switch. You want to cut the bottom of the nut and the threads off so the bottom of the switch is level. Once trimmed, the switch will now sit about 2mm lower than usual. It should look like this:
https://ibb.co/21kZ0wf7
https://ibb.co/m5F92JZ3
Once you have it cut, smooth the bottom surface with some sandpaper. You are now ready to attach the float switch to the inside of your water tank. It needs to go on a flat spot but not on the metal heating plate. I used Crazy Glue Gel to attach mine. Crazy Glue (or an cyanoacrylate adhesive) is 100% waterproof. Let the glue dry and you are done this step.
https://ibb.co/GfhWYdgQ
Optional, but encouraged step: To make sure the switch is working, use a multi meter on Continuity mode to verify the switch is working correctly. It should beep when the float ring is at the bottom of the switch and turn off when the float ring is about 1/2 way up. I poured water in the tank to make sure the amount of water needed to turn the switch off was where I wanted it to be.
STEP TWO: Running Input Tube & Wiring
We need to drill a hole in the humidifier tank holder to run out output hose and the float switch wiring through. I used a 5/16 drill bit. You want to locate the hole so it has direct access to the interior of the water tank. Here is where I drilled mine:
https://ibb.co/v4N5TfZD
You may need to cut open the rubber membrane below that hole with an X-Acto knife or razor blade. Once you have that drilled, run the two yellow wires up and out the hole.
Take the length of hose that came with the pump, and cut it in 1/2. Take one end of one of the halves and insert it into the hole, about 1/4 of an inch. You may need to squeeze the tube to get it in the hole, like this. You want a tight fit.
https://ibb.co/RGdRcT2k
Once you have the tube and wires run make sure the lid closes and does not foul anything. If it does, adjust as necessary. I zip-ted my float switch wires to the air intake tube in the tank to make sure they stay out of the way and don't foul the float switch.
https://ibb.co/v6rhyBgB
https://ibb.co/gLKD1PDC
Next you need to seal that gap and make it air and waterproof. Apply a thick bead of clear silicon waterproof sealant around the edge of the hole on both the top and bottom of the lid. Let this cure overnight to make sure a proper seal is established
https://ibb.co/bMjZRKMG
https://ibb.co/cXw95zNC
STEP THREE: Electrical wiring
Disconnect the bullet connector for the pumps power supply. You will notice that the black power supply wire is actually two wires connected. If you look at them you will see one of them has white markings on it, the other does not. About 1/2 way between the bullet connector and the pump, split the two wires apart using your fingernail or a toothpick or something. Take care not to damage the insulation.
We want to run the POSITIVE signal through the float switch. The positive wire is the wire WITHOUT the white marking. In the spot where you pulled the wires apart, cut the positive wire, and strip some insulation off to expose bare copper.
https://ibb.co/XrPGkmFK
Each of those ends needs to be connected to one of the yellow wires coming out of the tank. It does not matter which goes to which, just connect one yellow wire to one of the ends of the black wire and the other yellow wire to the other end o black wire. You can use any type of connection you want, Wago connectors, wire nuts or solder or whatever you please. I like using Wago's because it allows for easy disconnect while moving things around.
https://ibb.co/SDT1kbYS
At this point you should test to make sure everything is wired correctly. Plug in the pump and attache the bullet connector, and turn on the pumps power switch. The pump should turn on. Lift the float switch up with your finger, and the pump should turn off. Drop the float switch, and the pump should run again. If that checks out you are good to go.
STEP FOUR: Water tank setup and final assembly
You can use any type of water container you want as a water source tank. Take the other unused length of tubing and insert it into whatever you are using. I suggest using a rubber band to hold it in place.
Disconnect the bullet connector on the pump power supply. Take the other end of the length of tubing you just put in you water source and attach it to the SIDE port on the pump (intake port). Take the other end of the tubing you have coming out of your humidifier tank, and connect it to the port on the END of the pump (output port).
Make sure the pump power supply switch is OFF, and the CPAP machine is on a level surface. Connect the pump power supply bullet connector, and switch the pump on. If all went well the pump should pump water out of your water source and into your CPAP humidifier chamber until it reaches the correct level, and the float switch will then turn it off.
Congratulations! You now have a self filling CPAP Humidifier tank. As you are sleeping and the water level drops, the float switch will turn on the pump, it will refill your tank, the float switch will turn the pump off when it is full, and you will snooze right through the entire thing and never have to worry about running out of water in the middle of the night again. You can pretty up your set up as you see fit, just make sure none of the hoses get crimped.
https://ibb.co/6cBdtQhZ
WARNING
This setup has NO overflow protection. So, if for some reason the float switch failed closed, the pump would simply keep pumping all the water is had available, making a big mess. I have not found a simple way build in overflow protection, some ideas were to put in a second float switch for redundancy and wire it in series with the other switch, use a smaller water tank so if it does happen there's not to much water to spill, putting the CPAP machine in some sort of plastic tub, etc.
Also, if the reservoir tank runs empty, the pump will keep sucking air since the float switch will never turn off. If you want to prevent this you can insert another NC float switch in your water tank and wire it in series with the positive wire that will open the circuit if the tanks runs out of water.
I tried this as a "quick and dirty" project but been running it for a little over a week and it's worked flawlessly for me.
Parts & Supplies needed:
- 12V DC water transfer pump (https://www.amazon.com/gp/product/B0DB1T56HW/)
- Float Switch (https://www.amazon.com/gp/product/B07DZ1J2GB/)
- Silicon sealant (https://www.amazon.com/GE-GE284-Silicone...B000PSE46S)
- Dremel/Rotary tool with a cutting wheel
- 5/16 drill bit
- Crazy Glue Gel
- 100 grit Sandpaper
- Zip tie
- Rubber Band
- Pack of microfiber towels (you WILL get wet while doing this)
- Inline Wago connector
- Large fluid extractor
- Multimeter
DISCLAIMER/WARNINGS:
- You will be drilling a hole in your humidifier tank attachment of your device. If you have any sort of supplier warranty or anything on your device this will likely void it.
- You will be working with electricity and exposed wiring to put this together. Please use common sense and make sure all plugs and connections are unplugged from all power sources before handling them
- While it may seem risky to be working with electrical components in and around water, everything being used is designed to be in water, and distilled water is an extremely poor conductor of electricity so you have no risk of electric shock from it. That said, please follow these instructions at your own risk, I take zero responsibility for any damage or injury you may cause.
I have always had an issue with the humidifier tank running out of water in the middle of the night, causing a foul odor from the humidifier plate, and making my lips and mouth dry out as I slept. So I decided to build a self filling humidifier tank to solve the problem
PARTS NEEDED
First thing we need is a water pump. I went with this one: PlusRoc 12V DC Small Water Transfer Pump 1.3LPM Mini Self Priming Micro Pump with Food Grade Pipe and Power Adapter (https://www.amazon.com/gp/product/B0DB1T56HW/). $17.48 at the time of this writing
I like this pump specifically because it has a power supply with an independent switch on it, so you can kill the pump easily while testing. It is also quiet and will not wake me up when running. And it includes more than enough tubing needed for the project. And it's cheap.
Next, we are going to use a float switch to turn the pump on and off as needed. We need to use a float switch since distilled water is really bad at conducting electricity, so normal water detection boards and circuits won't work. We will need a NC (Normally Closed) float switch that fits inside our water tank and turn off the pump when the water is the appropriate level. After testing 4-5 different switches, this is the one I managed to make work: uxcell PP Float Switch for Water Pump Tank Liquid Water Level Sensor M12 2pcs (https://www.amazon.com/gp/product/B07DZ1J2GB/). $12.19 at the time of this writing.
STEP ONE: Modifying and attaching the Float Switch
Even as small as the float switch is, it is still to big to fit in the tank and turn off at the correct water level. You need to take a dremel/rotary tool with a cut off wheel, and trim the bottom of the plastic off the float switch. You want to cut the bottom of the nut and the threads off so the bottom of the switch is level. Once trimmed, the switch will now sit about 2mm lower than usual. It should look like this:
https://ibb.co/21kZ0wf7
https://ibb.co/m5F92JZ3
Once you have it cut, smooth the bottom surface with some sandpaper. You are now ready to attach the float switch to the inside of your water tank. It needs to go on a flat spot but not on the metal heating plate. I used Crazy Glue Gel to attach mine. Crazy Glue (or an cyanoacrylate adhesive) is 100% waterproof. Let the glue dry and you are done this step.
https://ibb.co/GfhWYdgQ
Optional, but encouraged step: To make sure the switch is working, use a multi meter on Continuity mode to verify the switch is working correctly. It should beep when the float ring is at the bottom of the switch and turn off when the float ring is about 1/2 way up. I poured water in the tank to make sure the amount of water needed to turn the switch off was where I wanted it to be.
STEP TWO: Running Input Tube & Wiring
We need to drill a hole in the humidifier tank holder to run out output hose and the float switch wiring through. I used a 5/16 drill bit. You want to locate the hole so it has direct access to the interior of the water tank. Here is where I drilled mine:
https://ibb.co/v4N5TfZD
You may need to cut open the rubber membrane below that hole with an X-Acto knife or razor blade. Once you have that drilled, run the two yellow wires up and out the hole.
Take the length of hose that came with the pump, and cut it in 1/2. Take one end of one of the halves and insert it into the hole, about 1/4 of an inch. You may need to squeeze the tube to get it in the hole, like this. You want a tight fit.
https://ibb.co/RGdRcT2k
Once you have the tube and wires run make sure the lid closes and does not foul anything. If it does, adjust as necessary. I zip-ted my float switch wires to the air intake tube in the tank to make sure they stay out of the way and don't foul the float switch.
https://ibb.co/v6rhyBgB
https://ibb.co/gLKD1PDC
Next you need to seal that gap and make it air and waterproof. Apply a thick bead of clear silicon waterproof sealant around the edge of the hole on both the top and bottom of the lid. Let this cure overnight to make sure a proper seal is established
https://ibb.co/bMjZRKMG
https://ibb.co/cXw95zNC
STEP THREE: Electrical wiring
Disconnect the bullet connector for the pumps power supply. You will notice that the black power supply wire is actually two wires connected. If you look at them you will see one of them has white markings on it, the other does not. About 1/2 way between the bullet connector and the pump, split the two wires apart using your fingernail or a toothpick or something. Take care not to damage the insulation.
We want to run the POSITIVE signal through the float switch. The positive wire is the wire WITHOUT the white marking. In the spot where you pulled the wires apart, cut the positive wire, and strip some insulation off to expose bare copper.
https://ibb.co/XrPGkmFK
Each of those ends needs to be connected to one of the yellow wires coming out of the tank. It does not matter which goes to which, just connect one yellow wire to one of the ends of the black wire and the other yellow wire to the other end o black wire. You can use any type of connection you want, Wago connectors, wire nuts or solder or whatever you please. I like using Wago's because it allows for easy disconnect while moving things around.
https://ibb.co/SDT1kbYS
At this point you should test to make sure everything is wired correctly. Plug in the pump and attache the bullet connector, and turn on the pumps power switch. The pump should turn on. Lift the float switch up with your finger, and the pump should turn off. Drop the float switch, and the pump should run again. If that checks out you are good to go.
STEP FOUR: Water tank setup and final assembly
You can use any type of water container you want as a water source tank. Take the other unused length of tubing and insert it into whatever you are using. I suggest using a rubber band to hold it in place.
Disconnect the bullet connector on the pump power supply. Take the other end of the length of tubing you just put in you water source and attach it to the SIDE port on the pump (intake port). Take the other end of the tubing you have coming out of your humidifier tank, and connect it to the port on the END of the pump (output port).
Make sure the pump power supply switch is OFF, and the CPAP machine is on a level surface. Connect the pump power supply bullet connector, and switch the pump on. If all went well the pump should pump water out of your water source and into your CPAP humidifier chamber until it reaches the correct level, and the float switch will then turn it off.
Congratulations! You now have a self filling CPAP Humidifier tank. As you are sleeping and the water level drops, the float switch will turn on the pump, it will refill your tank, the float switch will turn the pump off when it is full, and you will snooze right through the entire thing and never have to worry about running out of water in the middle of the night again. You can pretty up your set up as you see fit, just make sure none of the hoses get crimped.
https://ibb.co/6cBdtQhZ
WARNING
This setup has NO overflow protection. So, if for some reason the float switch failed closed, the pump would simply keep pumping all the water is had available, making a big mess. I have not found a simple way build in overflow protection, some ideas were to put in a second float switch for redundancy and wire it in series with the other switch, use a smaller water tank so if it does happen there's not to much water to spill, putting the CPAP machine in some sort of plastic tub, etc.
Also, if the reservoir tank runs empty, the pump will keep sucking air since the float switch will never turn off. If you want to prevent this you can insert another NC float switch in your water tank and wire it in series with the positive wire that will open the circuit if the tanks runs out of water.
I tried this as a "quick and dirty" project but been running it for a little over a week and it's worked flawlessly for me.
