Water Heater

This is the hot water tank under the sink.  It is a stainless box with a heat exchanger and a 6 gallon tank.  I was pleasantly surprised to find an electric heating element installed but not hooked up.  The element is 1500 watts and 110v.  I recently wired it for use while parked with electricity available.  The black lines are for engine coolant which circulates through the heat exchanger when it reaches temp.  I really like this system overall, but it's not perfect.  On the good side having hot water every time you stop driving is a wonderful thing.  The box is well insulated so the heat lasts a couple of days in mild climates.

When parked for more than two days this unit mounted under the truck can be switched on with a timer.  It runs on diesel fuel and will also recirculate the warm water through the engine. This can help with preheating a cold engine, but also makes the heating time much longer when you don't really need the engine warmed.  The best part of this system is that 80% of the  time I need hot water it's just there.  On the bad side it's a complicated system with much to go wrong.  Fuel lines exposed and engine coolant running front to rear.  Many places for something to go wrong.  I see this exhaust silencer in the picture.  I don't believe mine has that which would explain why it literally sounds like a small helicopter spooling up.  I'm talking loud enough to get the neighbors to come take a look.

I've had two minor problems with the system thus far.  I had to disassemble the hot mixer to find a failed O-ring.  I also had a coolant line leaking at the Hydronic outlet. UPDATE:  Yes there was a failed O-ring in the mixer and it worked better.  It still wasn't exactly right though.  I took it apart again and stared at it literally for hours.  I love these kind of puzzles something just wasn't right.  The mechanics didn't make sense.  I finally got smart and after a long search found the part online (made in Sweden). I realized it was originally installed wrong.  After this discovery it all made sense and 3 dollars worth of plumbing parts later all is well in the hot water world. 

I was really happy when I found the heating element.  When parked in my father's back yard the diesel furnace wasn't really practical because of the noise.  Love the fact that I can now just flip a switch.

Now the difficult question.  Would I install this system again.  The short answer is no.  I truly hate to say that because the cool factor is way up there.  If I built my own RV I don't think I could justify the cost.  I also worry a lot about the coolant lines chafing somewhere I can't see them.  I had a system down in my chinook for shower water.  I put a temperature sensor directly onto the hot water tank with a remote thermometer on the wall.  When the temp was right I turned off the heater and jumped into the shower with only the hot valve open.  No mixing and wasting water getting the right temp.  Yes I'm cheap, and yes my propane lasted a long time.


The water heater was only mostly working so I decided it was time to deal with it.  I found a guy online who will do a rebuild for around a hundred bucks plus parts.  Well, he quickly called me and stated that mine was heavily used and too old to rebuild.  For only $650 I could get a new one.  Yes I bought it, both the story and the new unit.  I've found that most times it pays to start over with an appliance especially one that rides outside of the vehicle.  So I put the new one on and fired it up.  It made a few whirring noises and never made another sound.  Grrr, I decided to walk away and see if it would do better later.  Sometimes these high tech parts need to have a time out.  No such luck.

I happened to stop by EarthRoamer soon after the install so I asked them about it.  They tested it for me and found the problem with the fuel solenoid.  Fuel solenoid disconnected or not working.  Hmmm.  I called my guy back and he said he has never seen one not work.  I could simply put 12v to one wire and ground the other to test it.  If it clicked it was working.  So under I go again.  When I unplugged the control plug to the unit the green wire fell out of the plug.  I bet you can guess where the green wire goes.  Yep, directly to the fuel solenoid.  Yay!!  It's such a good feeling when you troubleshoot and find the problem.  So I now have a very nice working hot water system.  As before, I almost never use the hydronic fuel fired heater.  I guess I move enough to have the water heated every couple of days.  It is also very nice to fire this thing up for hot water when parked for a while.  I also recently used the heater to preheat the truck before starting.  I didn't really need to since it was only around 30 degrees, but it was sure nice to have an already warm truck to start.

Ok, again, would I buy the system again.  At this time I think I'd go with serious solar and batteries and heat water electrically instead of dealing with these complicated water systems.