Having fun with the benefits of my cold fresh water system, I couldn’t just stop there. I decided to push through and finish my fresh water system by hooking up my hot water heater.
The heater itself (Brand: Isotemp – Model: 0220 “Magic”) I bought off of Craigslist in the Bay Area (thanks to Case for grabbing for me). It was originally designed for use in a sailboat. The cool thing about this 5-gallon water heater is that it is heated by coolant from the engine (or an optional 110v 750w heater, which I don’t really plan on using). The coolant enters the tank, runs as a coil through the fresh water and through an internal salt-box, and heats the contents rather efficiently. The salt-box is designed to absorb heat so when you use the hot fresh water it can replenish heat to the cold water that enters into the tank. And it works.
On the port used to originally fill the salt-box I installed a temperature gauge. When driving 10 miles the salt (and thus the water) gets up to 135 degrees. The hotter the water, the longer I have hot water (since I have to mix it down with cold water to not scald me). When I drive big hills and long drives, the water gets up to 165 degrees. Most hot water heaters are set to 115 degrees or so, so with the cold water mix down (and salt box), its like having a 7 or 8 gallon tank.
I use the water for washing dishes mostly, but just recently I added a bracket just outside the window above the sink. The bracket is designed for removable showerheads. The pull out faucet on my sink just so happens to have the same size base as a showerhead. This means that I can pull my faucet out, put it in the bracket, turn on the faucet, push the button on the faucet to put it on the spray setting, and voilà, a hot shower on the side of the bus. Oh, and I can control the water temp of my shower because I can reach in through the window and access the faucet handle.
The first time I tried this I had driven one mile the night before, one mile that morning, and idled for 10 minutes. This gave me 125 degree water. I thought I might be sparing with the water, so I got wet (ahhh, nice hot water), turned it off, soaped up, and rinsed off. All of this took about 2 minutes of hot water. I decided since this was the first time I might as well see how long the water lasted. It felt good because it was slightly overcast and cool, but after 5 minutes I got bored. Wow, enough hot water to get bored! Overall I think there was about 7 minutes of hot water. I think this means that when the water is 165, it would be nearly 10 minutes of hot water. That’s an easy two or three (or four) showers (at least for people like me).
After I showered I just had to laugh. It was one of those moments where you realize that a creative thought you had been brewing in your mind had actually become reality. Even after I had showered and a little time had passed the salt tank replenished some of the warmth and I did some dishes with warm water. This system works great!
Of course, I had a leak though, on the cold water inlet. For some reason this was a metric 15mm compression fitting and it needed a new compression ring. You just can’t buy metric compression rings in the US. I had to special order some from England.
The next step is to get my Webasto (model TSL-17) diesel-powered coolant heater and circulator hooked up. This will allow me to heat coolant in my system and circulate it to heat my water heater (among other fabulous things) without running my bus.
UPDATE: 9/12 – Tested the hot water for anti-freeze with a special test kit. It came out negative (thank you!). I did this out of the very off chance that somehow the coolant coil in the hot water tank was leaking. But it’s not. I’ll probably test it once per year.