Water System

[Weaselblade]

Slowly plugging away at installing my system, and considering a potential problem. Perhaps you know it to be a non-issue, or perhaps it needs solving in your plan as well as mine...

What stops the pressure building up in the heat exchanger and blowing the lines/connections, when you're running the engine and not using any water? After a while it would surely reach nearly the same temp as engine coolant, with nowhere to safely expand/vent that I can see.

The accumulator can't help, as it's on the wrong side of the check valves for this purpose. And if it was on the other side of the check valves, you'd end up with an accumulator full of hot water after long drives, with no way for the tempering valve to do its job...

 

[Ozarker]

Sounds more complicated than I imagined, but you need a pop off valve to let off the steam and hopefully that will be vented outside.

I guess my system is too simple, a water tank, one inlet for a hose, if no hose hook up a funnel with a short hose, water filter to pour water in. Propane on demand heater. All PEX and brass fittings. 12v pump.

Where is your drain for grey water, some place you can't discharge grey water or throw it out of a bucket?

Sounds like the mind is pretty well made up, but what's wrong with this?

http://www.amazon.com/Rheem-RTE-Ele...22&sr=8-4&keywords=10+gallon+hot+water+heater

with a generator. or a propane type?

 

[Mwilliamshs]

Sounds more complicated than I imagined, but you need a pop off valve to let off the steam and hopefully that will be vented outside...

How often does the pop-off valve on your engine's cooling system open to release steam? (hint: ya ain't got one) There is a radiator cap that holds ~13 psi on that sealed system and it will open if your cooling system is overfilled or the engine overheats but again, that's a sealed system and my hot-water loop isn't. Furthermore, the radiator cap protects the water heating system from overheating. In my system there should be no steam, ever. Basically impossible. Steam would require an input temperature (engine coolant temp) of over 212*F which would mean my engine was overheating (considerably) and had been doing so long enough to superheat the water on the output side of the exchanger. The radiator cap has popped by now btw. The heat exchanger is pretty efficient but there'll always be some heat loss so realistically you're suggesting that my engine would be >220* and the heated water would be stagnant in the exchanger long enough to absorb enough of this heat to create steam. This is all at an idle btw. While that is a possibility I suppose, it's certainly on the far backside of remote. If all of that did happen, the steam would have to pass through the tempering valve (half-filled with cold water) in order to be discharged. I've heard tempering valves on boiler systems (which this is not) "chatter" as steam met cold water and the valve rapidly mixed the two but I've never seen steam escape the valves. This was the result of failed electronic controls, which I'll not have.

...Where is your drain for grey water, some place you can't discharge grey water or throw it out of a bucket?

A bucket with lid can be set beneath the drain of the sink to be disposed of later but really, when you're on an extended trip and not just going from a-to-b, why camp in such a place where that's the rule?

...what's wrong with this?
http://www.amazon.com/Rheem-RTE-Ele...22&sr=8-4&keywords=10+gallon+hot+water+heater with a generator. or a propane type?

A generator takes up space and has little benefit. No way I'd add one just for hot water. A residential electric water heater would likely live a short life in a van traveling South American roads. The one you linked to has only a 1 year warranty on its heat exchanger and that's applicable only if the unit is installed professionally. A propane water heater, whether on-demand or tanked, burns [lots of] propane which is the least plentiful fuel in the van. They also must be vented (holes in the van) or mounted outside (messy + holes in the van) or portable (messy). I prefer the heat exchanger because it's compact, uses waste heat of the engine, and installs cleanly. There are also no moving parts, controls, electronics, etc. It's as simple as can be.

 

[Ozarker]

Still looks complicated to me, but whatever, obviously you like it. Are you going to start marketing a kit?

I probably misunderstood with the post concerning built up pressure in the fresh water loop, didn't realize it would never get that hot, but I am familiar with residential loop systems.

You're probably right, that HW tank probably wouldn't do well in a van, the suggestion came from motor home owners throwing out the trashy tanks and using residential tanks. But, we have the instant HW products heating water on demand, even residential units that might be cheaper and could be adapted, less space, fewer plumbing connections, simple, clean.

If you ever get around the sites under the Corps of Engineers, Bull Shoals, Taneycomo (White River), Table Rock (all in AR ) they'll tell you not to throw out the bath water, take it to the dump station. I generally stay on the Mo. side.

IMO, the fewer connections the better, don't recall a plumbing connection that never leaks.

Run my engine to get hot water? So, the guy in the next spot won't mind my exhaust blowing his way or mind listening to my truck running? I understand being in the back 40, but I'm not always in the back 40.

You've put a lot of research and study into your system, good luck with it and hope any kit you make does well for you.

 

[Mwilliamshs]

...Are you going to start marketing a kit?

No.

...If you ever get around the sites under the Corps of Engineers, Bull Shoals, Taneycomo (White River), Table Rock (all in AR ) they'll tell you not to throw out the bath water, take it to the dump station. I generally stay on the Mo. side...

I love camping in that area. Bull Shoals State Park especially. The sink drain has a regular garden hose fitting that can run into the campground sewer connections or again, into the bucket with a lid. Carry the bucket to the bathhouse each night at shower time and pour it in a toilet. I have no bath water. State Park bath houses work well for me (no clean up, no dump station visits, no problem) and a porta-potty stands by for sudden use. Even when camping in my real camper I use the bath houses for showering and toilet needs. The less I use an RV toilet and have to dump raw sewage, the better.

...IMO, the fewer connections the better, don't recall a plumbing connection that never leaks...

Big bonus of the homerun style system with pex. Zero connections hidden within walls and as few total connections as possible.

...Run my engine to get hot water? So, the guy in the next spot won't mind my exhaust blowing his way or mind listening to my truck running?...

In the campgrounds you mention, which I frequent, the campsites are far enough apart that a gas engine doesn't pollute the next site with fumes and my 4.9L engine is pretty darn quiet. Again, those campgrounds have bath houses, so I use them. The van does have an aftermarket muffler and functioning catalytic converter. It doesn't stink and it's not noisy. In fact, I was sitting inside my running van one morning very recently (waiting on dad to go launch the boat) and could hear the propane water heater in the next site burning pretty distinctly. It was my parents' 5th wheel and we were camped at...Bull Shoals State Park. I commented to dad that mom must've been enjoying bath time with the grandbaby cuz I heard the water heater cycle quite a few times. The trout in the White River were not biting The trout at Gaston's were delicious

Lots of folks in campgrounds idle their diesel tow rigs to warm up their interiors in the winter, cool them off in the summer, and leave them running when hitching to leave, etc. I'm quieter than they are. A $50 remote start kit means I can start and stop the engine at will with ease. I really might look into an oversized genturi type exhaust though. Hadn't considered it till now but that could be a fun project. I built the one on my folks' 5th wheel (propane Onan) generator for about $70 and think it'd be even cheaper given the van's more standard exhaust pipe diameter.

This rig is not intended for campgrounds. I have a Lance slide-in for that or just drive up and meet my folks for the weekend. This is the rig for heading to Argentina when I graduate, camping out at dirtbike trails, boondocking in the deer woods, etc.