On Board Hot Water Shower System

[Borrego60]

How about a holding tank with a circulation pump that cycles the content thru a plate heat exchanger and simply has a thermo sensor on the pump circuit such that you switch the system on and it circulates the water while you are driving and auto-cuts the circulation pump when the set temperature is met. No mixing, no dual tanks, no excess plumbing. And the thermo will cut the pump back on if the tank temp drops before you are parked.

I really like that idea to use the rear heater circuit too, plumbing wise. BUT that means you'll be heating the rear of the vehicle. There usually isn't an 'off' on the rear fan system.

Positioning the tank just so and it would be like a hot water bottle for your sleeping arrangements, in winter.

I recruit my water so much easier and faster than a mixing valve. and a constant temp too. No worries about being burn.

 

[EverRidesurf]

That makes sense, not sure if I am overthinking it, the only thing I was really thinking of adding that I don't see mentioned here are those bulkhead fittings. Here's a diagram of my plan
View attachment 409481

I'm going to add the heat exchanger later.

I could probably hide the ball valve (source selector) along the frame rail. As for the fill port, QD input, QD output, and spigot, I see your point about protruding fittings. I could maybe make something recessed... but not sure my skills are up to it.

I'm installing an onboard air system at the same time, which involves a regulator, dual needle gauge, and QD fitting that I wanted to put on the same panel as the water.

I'm just a little hung up on the fittings and how to mount them properly.

Don’t know if you already installed this but check the pump. Most pumps work better on a pull. So moving the pump close to the exit point works best. I had horrible pressure and ended up removing mine because of this only to find out pump goes close to outlet.


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[onesojourner]

Has anyone noticed reduced heater function with one of these before or after the heater core?

 

[ohiobenz]

Resurrection of an old but good thread...
I read it from the beginning and got a lot of good points like the anti-scald valve...
My rig is centered around single fuel use - diesel. Hot water is apparently the hardest item to have efficiently, but important.
So bouncing my plan and hoping some of the posters from years ago are still around to share their experiences.
I have a 5 gal under counter water heater/tank, an Eberspacher diesel fired hydronic heater. The plan is to put the Eberspacher into a direct circulatory loop with an anode rod in the WH tank for anti-corrosion, a low volume circulatory pump and an expansion tank for pressure increases. Thermal switches would determine the upper and lower circulatory temp limits and control the Eberspacher, anti-scald valves at the shower and sink to control point of use temps.
Separate pumps for the hot and cold that are pressure drop activated like a typical RV setup.
A simple hot water heat vent valve would eliminate air in the system which is detrimental to the Eberspacher function.
Most hydronic systems use an interchange system, but at least one guy on the cruiserforums has a similar direct heating system because he only had an outboard motor with no coolant system.
I will most likely build and bench test the system. The current 120vac WH element will be replaced with a 48vdc element as a backup and way to dump excess power from the solar panels battery bank.
Not sure about fresh water tank size, but I've already built a portable filtration system for fresh water draw from streams etc. Endless showers would be a dream come true lol.