Can I get some advice on my plumbing plans?

[Rather Diesel]

I set this up as three separate loops of liquid, coolant-coolant-freshwater.

I am wide-open to input on this. Please ask for clarification if needed.

Thanks for your help.

Roy

[StumpXJ]

Hi, I am currently setting up a freshwater ciculation/heat exchanger system also, for use with a shower. I am only using one heat exchanger that will circulate water (hot) back in the holding tank until needed for use. I am trying to figure out in your drawing why you are using two heat exchangers? Im sure I will set-up some sort of sink type fixture to use for dishes also, but will just have my valving setup to not go through the heat exchanger, but pump cold water directly out of the tank. (unless I need hot water, then it will be the same as if I were preparing a shower.) can you clarify you intents with this set-up?

~James

[njtaco]

You asked for advice...

Only one heat exchanger needed, unless you have a compelling reason to include a second.

You will need a small expansion tank on the demand side of the water pump, so the water expansion does not overpressurize the system. An RV water heater has a pocket of air in the top for this purpose, and a temp/pressure relief valve as a backup. I see neither in your plan above.

Actually, a small marine water heater (coolant-water) may be worth looking into, if you haven't. You would have hot water for a bit when the truck is not running, and an electric element to run on shore power when available. It also provides a few gallons of "emergency water" in a built-in tank. Just a thought...

Consider a small cabin heater in the system, since you already plan to run coolant to the rear of the truck. That way the back of the truck stays warm, without overheating the driver while underway. This could be valved in a seperate loop so it can be shut off in warm weather.

Last, I would consider using hot water to rinse the urinal...

[Rather Diesel]

Thanks for replying. I didn't add any valves, etc., because I wasn't sure where best to locate them. I did plan on a second heater core in the rear for just the reason you stated.

I'll investigate your other suggestions as well.

Roy

[Rather Diesel]

Hi, I am currently setting up a freshwater ciculation/heat exchanger system also, for use with a shower. I am only using one heat exchanger that will circulate water (hot) back in the holding tank until needed for use. I am trying to figure out in your drawing why you are using two heat exchangers? Im sure I will set-up some sort of sink type fixture to use for dishes also, but will just have my valving setup to not go through the heat exchanger, but pump cold water directly out of the tank. (unless I need hot water, then it will be the same as if I were preparing a shower.) can you clarify you intents with this set-up?

~James

I'd like to clarify, but I would need to know what the heck I'm talking about in the first place. :D I am brand new to RV-type water systems, so I needed to start somewhere.

I guess a good question, after reading YOUR question, is "Will one pass thru the heat exchanger get it up to shower temp?" I like the idea of setting it up to recirculate until the temperature is hot enough, but I don't know if it's needed.

The reason I was considering two heat exchangers was because I thought it would give me more control over the hot water over all. And, subsequently more control of a rear heater, etc.

Roy

[StumpXJ]

No worry, im as new as you are! I wondered the same thing as to whether one pass through a heat exchanger would be enough to get it up to temp, and I have my doubts. (my Wife likes a HOT shower, warm probably wont cut it, and she is the main reason im doing this...besides the fact that its cool.) I have worked with heat exchangers in dialysis (medical) systems before, they work great but it was circulating type system. Thats the reason im going with circulation, and pump it back into the tank until it gets to the temp I want then I would use it. I plan on having a temp probe in the tank that will have a gauge in the cab or in the camper sheel area somewhere.

My set-up (in my head) will be pretty simple really, Ill draw it up like I "think" it should work and post on here. Im sure we can figure something out. My tank should be here any day, and I already have the shur-flo and most of the other items. (got my tank from here, very cheap and great people to deal with, its going where the spare tire used to be under the truck. http://cgi.ebay.com/ebaymotors/ws/eBayISAPI.dll?ViewItem&ih=015&sspagename=STRK%3AMEWN%3AIT&viewitem=&item=250082002411&rd=1,1 )


~James

[Joaquin Suave]

Heres my dos centovaos...

Leave your motor alone! I believe in isolating the motor completely by having a seperate h20 and electrical systems for your shelter and motor so that when you shelter systems go down (don't worry they will!) you can still drive home!

or you have back-up h20 and batteries in your motor systems goes down.

In Casa Azul I have an RV h20 heater (10 gallon) and don't like it very much! I believe that RV "systems" were primarly designed for RV's to be cozy campgrounds as opposed to wind blown beaches in the middle of nowhere where we spend most of our time. I've had to "re-set" the ignition system countless times and if the heater is left on...it will suck up a bottle of propane in no time. we now make a practice of heating h20 for dishes on the stove and fire up the waterheater only on "shower nights".

Before Casa's next Mexico trip, I plan to research then buy and install an "on demand heater" and swap it out with our current one.

I think that using a heat exchanger system isnt the wisest use of your resourses for a couple of reasons...

In Casa, we often camp in one location for weeks at a time (usually in DEEEP BFE) and try to get THE MOST out of our resourses (especially H2O, propane, and diesel). Since we have PV panels our batteries are constantly charged so we have no need to fire up the motor. In parts of Baja, fuel can be scarse and I want to make sure that every drop of diesel is used to get us "to and from", and that we always have a reserve in case the Pemex stations didn't get their fuel shipments (like over the last Xmas holidays). I've heard of people camping a Pemex stations for 3 days waiting for fuel! YUCK!!!

So needless to say, firing up your motor just to take a hot shower is a waste of fuel in my book. Run out of propane...Drink warm beer. Run out of diesel...walk!

You've got a small rig...Why don't you just use a Solar Shower? I use on when I camp in Mayahual (my Jeep scrambler)...They ROCK! The money you save can go to PV panels and the time you save can go to...

EXPLORING!!!

PM me if you need a source for h20 tanks

[Desertdude]

You could consider adding one of these Isotherm water heaters (http://www.isotherm.com/squarewater.htm) they run on engine water as well as 110v - add an inverter and you have the best of both worlds

[njtaco]

:iagree:

The Isotherm is the type I was referring to above, but not one I have used myself. Looks good on paper though, and I like the mounting versatility. You would have to swap out the immersion heater for a 110V, 24V, or 12V, though.

I also agree with Joaquin Suave...keep the engine as isolated as possible/practical, and redundant systems are a good thing. Isolating valves in the coolant system would be a must, for both the rear heat and the hot water systems. Also, RV propane powered conventional water heaters can be trouble-prone, as noted by Joaquin.

JS, do you source tanks, or make them? Plastic or St. Steel? Inquiring minds want to know!

[Grim Reaper]

I'd like to clarify, but I would need to know what the heck I'm talking about in the first place. :D I am brand new to RV-type water systems, so I needed to start somewhere.

I guess a good question, after reading YOUR question, is "Will one pass thru the heat exchanger get it up to shower temp?" I like the idea of setting it up to recirculate until the temperature is hot enough, but I don't know if it's needed.

The reason I was considering two heat exchangers was because I thought it would give me more control over the hot water over all. And, subsequently more control of a rear heater, etc.

Roy

I am trying to find a link but there is a double heat exchanger set up used often on UniCats and similar set ups. When the engine is running it provides the heat for the camper with a air to coolant and a Coolant to water exchanger. When the truck is not running it has a Diesel or other fuel powered heater. The set up allows you to preheat the engine coolant as well.

I know I bookmarked it but just can't seem to find it. I believe the heater was made by Espair (sp).

[Grim Reaper]

Here is one of the companies that makes these style heaters.
http://www.webasto.us/am/en/am_rv_heaters_819.html
The build I was looking for that had a nice diagram and explanation is on the links of this page.
http://www.rockymountainmoggers.com/links.html

About midway down is the personal pages. The guy was building a U1300 expo camper with a composite body and had a Lot of great information.

[Joaquin Suave]

JS, do you source tanks, or make them? Plastic or St. Steel? Inquiring minds want to know!


I have a relationship with a PVC rotomold tank manufacturer that offers a LARGE selection of tanks. They however are "industry only" and don't sell to the public (and would be pissed off at me if I sent a bunch people to bug them.)

If you have a specific size tank your looking for let me know. I wouldn't mind making the call and catching up with them.

[Rather Diesel]

I love the idea of being able to pre-heat away from 110v power. If you can find it, that would be great.

Roy

[Rather Diesel]

Great! Thanks for all the assistance. I need to do some reading and planning before i pull the trigger on the next step.

Roy

[Desertdude]

I am using that isotherm water heater in my 80 series it works quite well along with a xantrex 1800 watt invertor

--------------
Bought a few poly tanks from HERE (http://www.pplmotorhomes.com/parts/rv-pumps-water-filters-fixtures-1.htm#Water%20Tanks%20-%20Rv%20Fresh)

no smell, no fuss, inexpensive

------------------------
Jonathan Hanson had a SS tank made here (http://expeditionportal.com/forum/showthread.php?t=1852&highlight=stainless+steel+water+tank)

[njtaco]

I am using that isotherm water heater in my 80 series it works quite well along with a xantrex 1800 watt invertor




DD, The link you posted above shows a 230V element...Did you order one with 110V element, or are you using 110V with the 230V element? Or can you get 230V from the Xantrex? (I haven't looked it up...)

I'm liking the isotherm more and more...

[Desertdude]

I bought the slim/square_4.2gal. 110v isotherm from West Marine (http://www.westmarine.com/webapp/wcs/stores/servlet/product/10001/-1/10001/255476/10001/28/27/11) along with the xantrex invertor (http://www.westmarine.com/webapp/wcs/stores/servlet/producte/10001/-1/10001/250946/0/0/xantrex/All_2/mode+matchallpartial/0/0)

[njtaco]

I bought the slim/square_4.2gal. 110v isotherm from West Marine (http://www.westmarine.com/webapp/wcs/stores/servlet/product/10001/-1/10001/255476/10001/28/27/11) along with the xantrex invertor (http://www.westmarine.com/webapp/wcs/stores/servlet/producte/10001/-1/10001/250946/0/0/xantrex/All_2/mode+matchallpartial/0/0)

Thanks!

[Rather Diesel]

Wow, that's nice, but they sure aren't giving it away!

I was trying to keep this a budget build. So far,I've made almost every part myself. With the trips I plan, I can't really justify a $1000 heater setup. I can certainly understand it for the hardcore guys on this board though.

Thanks for the links.

Roy

[StumpXJ]

Im with Roy, I agree thats a very nice unit.... but ive got 70 bucks in mine so far (pump and tank, homemade heat exchanger, hoses...blah blah) and it does the same thing. whewww... I can buy a lot of other goodies for the truck for 600 bucks.

~James