Hot Water

mkuper · 12-03-2013, 01:03 AM

This is my first van build. I really want a hot water system but do not want to install a propane hot water heater if I dont have to . I am interested in some of the heat exchangeres I have seen on the forum but wondered if anyone had set somthing up with a hot water tank. Could you use the hot engine coolant to heat water in a tank perhaps with a submerged heat eschanger?. Wouldnt this allow for hot or warm water to be used without having to run the engine to keep the heat exchanger hot? Sorry if this has been discussed, I searched but came up with a ton of un-related stuff.

Thanks
Mike

As soon as I figure out how to post pics I will put some of of my project

**daveb** · 12-03-2013, 07:51 AM

Search Hydronic for one. Espar make a diesel version but not sure about a gasoline model. Some of our European friends probably have an idea for you.

There are some who use standalone tankless water heaters and things like the Zodi style.

E350 · 12-03-2013, 08:42 AM

I have a Webasto Dual Top diesel furnace/hot water heater which draws from my fuel tank.

I have only used the furnace part.
The Dual Top has an electronic drain for the water, which should be helpful in freezing temps in the Winter when the furnace or water heater is not on.

But I haven't plumbed it yet for water, so I don't really know how it will work.

As far as a heat exchanger from the engine goes, yes, you can get one.

Check out Blue Heat in Canada, Espar and Webasto.

However, if you have a diesel, we are more concerned about putting heat into the engine and I would be reluctant to remove heat from the engine. That's why we have plug in engine heaters, fast idle tunes, etc.

IMHO it is more efficient to burn diesel to heat a proper water heater than it is to run the engine on diesel to warm the engine to warm water to use for hot water.

schluchtenflitzer · 12-03-2013, 09:50 AM

You can go to a boat shop and buy a hot water boiler. This guys are made fot heated with engine hot water and 12/110V. They are good isolatet so the keep about 3-5 gallons of water hot for about 24hours.
I also insalled one and it works perfekt! I combined it with a webasto water heater but only for the reason i stand on one place for long time and will not run the engine.

see here (not conected to the engine at that time)

here some of them
http://www.nauticexpo.de/prod/indel-web ... 04588.html

best you can do at your smb

E350 · 12-03-2013, 11:05 AM

schluchtenflitzer: Very cool! What pump and diverter/valves do you use to pressurize and use the system for faucet or shower?

schluchtenflitzer · 12-03-2013, 12:47 PM

I use a std surflow pump. No valves but to train the water in winterise and one for overload pressure while getting hot. -very importand! -

aproximately like this. Sorry not in english ;-)

E350 · 12-03-2013, 01:48 PM

schluchtenflitzer: Thank you for the diagram.

I notice that you have not included your Webasto diesel water heater in the diagram. (Like you, I often stay in one place while camping -- and often in a place without electrical shore power hookups.)

Hey you SMB plumbing experts: do you normally use an ausdehnungsgef in your designs (i.e., an expansion vessel)?

In a house yes, but in an SMB? I don't know why it would be any different, but I have never thought about it in a SMB.

schluchtenflitzer · 12-03-2013, 02:25 PM

The diagram is not from me and is only an overview "how to make it" from an dealer

My webasto water heater is just in line with the engine water tubes. I do not know if this works with all. Mine (old one) webasto has an waterpump which is "open" so it do not need to run to let water pass.
I also have no expansion tank. Some say it is usefull to have always the same water pressure in your system. So more comfort and the pump has not to run so often for short time. I have no problems without. I think it is because my waterlines are very long and of course also the hot water boiler (4 gallon) is able to expant a little under pressure.
This expansion tanks are huge and i want not loose unfull place for an unusefull part.

E350 · 12-03-2013, 02:35 PM

Danke. I am intrigued by having both the electric and the diesel water heaters. (With the electric inside the living space, serving as a water tank.) One for use with hookups (although most places with hookups usually also have showers, hot tubs, and the like) and one for boondocking (most of what my wife and I do).

mkuper · 12-04-2013, 01:01 AM

Thanks for the info, I will check into the marine units.

Mike