Turn an old coffee maker into an on-demand water heater (nevermind)

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Picture of turn an old coffee maker into an on-demand water heater (nevermind)
Update:  Nevermind this one.  Too many electrical shock risks to make it advisable even as an experiment.

Hey guys, this was a fun and novel idea I had but on retrospect, I don't think it's really something safe enough to recommend for people to try for realz, so I am deleting it...

Thank you for reading!

Step 1: Are you forgetting something?

Picture of Are you forgetting something?

Did you read all the safety warnings and follow them?

Are you sure you want to do this?

Did you feed the cat? 


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cnathan2 years ago
I actually made a homemade water heater using a coffee maker and some other supplies. I travel in a motor home and do not like using LP gas so I ripped out the gas heater and built a rather cheap but efficient water heater. All in all, I spent maybe $60 to build and took a day to construct. I made a supply list and step-by-step instructions but it's not letting me add photos. I made a 20 gallon tank and it takes about 6 to 8 hours to get around 110-130 degrees. The only problem I have had with it so far is if I use well water, I have to clean the water lines once a month as lime and calcium build up. I use vinegar to clean lines.
foobear (author)  cnathan2 years ago
Awesome, good to hear that this idea can actually work. I got so much flack for this one that I deleted most of the article. Maybe you will post an instructable that people will appreciate.
Used this years back to heat a hot soaking tub for my wife. You don't need a pump just put the coffeemaker at the water level of the tub and add a siphon hose to put the water back in the coffeemaker tank, that will make the two water level stay equal. Works great except the pot would calcium up after about 2 months of continual use and have to be replaced. I've since gone to a 5 gal bucket heater and a waterbed thermostat teaked a bit to raise the temp to 110 degrees.

foobear (author)  Rayvillian9134 years ago
desertdog4 years ago
Interesting approach. Reminds me of a guy I know that used the heating element from an electric hot water heater heater to achieve the same thing.

As far as I know he is still alive.
DragonDon1 year ago
Well this is disappointing. Heck, quite a few things here are a 'bad idea if you don't understand the risks'.
foobear (author)  DragonDon1 year ago
Yeah, I tried to delete this one, but it was in a contest, so I couldn't
mikesnyd4 years ago
What is the aproxima GPM output of hot water? Thanks. I was just wondering how long i am going to have to wait for a tub to be filled. I have a small 100L tub i want to fill for my camping expiditions. due to the girlfriend not wanting to camp unless she has hot showers/baths everyday. Thanks
Can someone say sketchy? Haha, don't kill yourself with a coffee maker next to a bathtub.
Cartuner554 years ago
Damn, forgot to feed the cat.
So did I. Anyone want to loan me a cat so I can feed it and get past step 3?
fly_boy_bc4 years ago
Why not READ the instructable before submitting a critical comment?

"Not sure it wouldn't be easier just to turn on the hot water to re-heat the bath"

The FIRST PARAGRAPH tells you why he does not do this.

I have EXACTLY the same problem AND I have a spare (and gutted) coffemaker I was using as a distillery. I will be lounging in warm water all night!

Sorry for overlooking that point, but I wasn't being critical. I love the idea.
espdp24 years ago
That's what the cat is for!
Of course! That's why we had to feed the cat! He's our TEST BATHER!
You don't need to start a siphon the coffee maker already does that normally when you use it to make a pot of coffee. That is why the water in the tank in the back of the pot doesn't get hot and all the hot water ends up in the pot. The key is there is a ball valve inside the heating element so when the water heats up it expands and creates lower pressure on the hot side drawing in the cold water past the ball valve which in turn gets heated up. That is why you don't have a pump on the coffee maker in the first place.
The ball valve is also the part that gets kludged up with lime and you have to clean it with vinegar or it gets too hot and you burn out that little heat fuse. I like the bike tire (cheap and easy) but it might be better with silicone tubing to withstand the heat hate to have the tube leak in the middle of a nice bath.
Oroka4 years ago
Interesting project, but how big is your water heater? Unless it is teeny tiny, you should be getting a lot more hot water out of it. Perhaps a element is burned out or something.
foobear (author)  Oroka4 years ago
It has just enough capacity to fill the tub once only. It requires a 30-40 minute wait to heat up all its water again.
Oroka foobear4 years ago
wow, that is quite small.

Used hot water heaters really are not that expensive. As long as the tank is solid, the rest of the tank is pretty simple.
foobear (author) 4 years ago
I assume you mean the hot water outlet of the coffee maker and not the tub.
foobear (author) 4 years ago
Certainly, don't try this at home.
jptrsn4 years ago
Check out http://www.youtube.com/watch?v=4j4Q_YBRJEI

It explains how the coffee maker works without a pump. That means that if you take the heater assembly, hack both hoses into the tub, and keep the whole thing lower than the water level in the tub, it should work without a pump.

Use really long hoses, and you won't have the safety hazards that this project entails.

Let us know if you work on it more! 

foobear (author)  jptrsn4 years ago
I like this idea. It's very simple. I'm not sure how to easily get the siphon started to get the water flowing from the tub to the element though.
jptrsn foobear4 years ago
If you've got enough of a length of tubing, getting the siphon started is pretty simple. I use the following method for cleaning my fish tank and draining the swimming pool:

1) Submerge as much of the tube as you can in the water.
2) Cap the open end of the tube (a thumb comes in handy here).
3) Pull the tube out so that the water in the tube goes up over the edge and comes down to a level lower than the surface of the water.
4) Remove thumb.

As long as the water in the tube is lower than the surface, the pressure differential will push water through the tube. Get the water going, then raise the open end of the tube and put it back in the tub. As long as it's primed to the heater element, it'll draw cold(er) water from the tub.
foobear (author)  jptrsn4 years ago
I see what you're saying. I'd like to find an easier way though.
espdp2 foobear4 years ago
How about one of those squeeze bulbs for a marine outboard motor's fuel tank? A few squeezes will push water up and over the edge of the tub, and the bulb will let it keep flowing in that direction.
foobear (author)  espdp24 years ago
The problem is you'd have to somehow squeeze it from the device side to get the cold water flowing into it. Just having trouble visualizing how to hook that up.

Using something like that, I think you could come up with a slightly more elegant and less dangerous kludge.
foobear (author)  DeusXMachina4 years ago
interesting. I didn't know about this device. thanks
If you are gonna play around with this, then you need to replace the electrical outlet in your bathroom with a GFCI outlet and make sure the coffeemaker is properly grounded. PLEASE do this, it could save your life!
foobear (author)  computurwizard4 years ago
I thought GFCI outlets were required by code in all bathrooms. I don't know. Maybe not in every state.
foobear (author) 4 years ago
Definitely don't try it if you feel like that. Stay safe.
sheilamommy4 years ago
Room's ambient temp 51 degrees. And I thought I kept my house on the cool side. I will show your instructable to my kids to let them know how goodthey've got it at 65 degrees.
foobear (author)  sheilamommy4 years ago
Yes, I bought an old fixer upper and it has no insulation anywhere! So, even with all the heaters on and the fireplace, we couldn't keep it warm enough. Outside was 20 degrees or so.
espdp2 foobear4 years ago
Hire a teenager to put in some fiberglass and spray-can insulation. It will save you lots of money over running the heaters and fireplace. Anything is better than a drafty box.

Also, you should look into a pellet stove. They are just about the greenest heating solution out there, not TOO terribly expensive, and easier than a fireplace to keep going.
foobear (author)  espdp24 years ago
certainly good advice
foobear (author) 4 years ago
Thanks, that was constructive feedback.
fly_boy_bc4 years ago
This is exactly the way to do it and I assumed it was the way this instructable worked before I read it. Really easy to imement and no syphoning difficulties.

I think it will be easy to make sure it is safe too. Just make sure there is no way for the coffemaker element to get wet. (on he outside) NO danger.

WingDings4 years ago
:D Lethal!
I use an old water bed heater for the heatpad for seed starting. Put the heater in the bottom of a wood box with 1x4 sides. put a plastic sheet to keep water from the heat element than 1 1/2" wet sand on top to spread the heat out. Thermostat bulb buried in the sand controls it. You have to add water occasionally.
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