My hair brained mod

[shovelhead]

Bare with me.  I've taken many a submarine shower and at my age I need plenty of hot water for these old bones to feel better.  Nearly an impossibility with a 6 gallon hot water tank.  I'd like a  tankless heater but there doesnt seem to be a RV version that is economical (price + installation) & dealing with ventilation issues.

Now my hair brain idea:
I have  portable tankless outdoor water heater.  It works fine and I can take my 15 minute hot shower "outdoors".   What if I just connect the tankless water heater  to the CL city water input?  I now have hot water without the 6 gallon limitation. Granted no cold water but I dont use tap water. I use bottled water for cooking, coffee etc.  I basically do this at home with my water heater thermostat set for "shower" temperature with zero cold water to cool down.  The dishwasher runs about once a week and has it's own water heater for sanitizing.  

I could also  turn off the tankless water heater and allow the internal heater to operate nomally until the next shower.

Hair Brained?

[pinstriper]

1. Last time I was under there, it looked like they used 2 different colors of PEX for hot and cold.

2. I would expect the line from the city water to be of the "cold" variety.

3. As far as I know, there is zero difference between the "hot" and "cold" PEX, beyond color.

So basically all the plumbing should be up to spec for hot water throughout and this hair-brained idear should work.

I think you could also dial it back and not have it run shower-temperature water, and let the 6 gallon heater complete the runup.

That having been said, if you are taking a 15 minute shower you are on a hookup, and that means you probably have a bathhouse/shower at the campground. Unless they're totally gross, I would always use their shower. At least that's what I've done so far. I have used the outside hose do run some shampoo through my hair and sponge the smellier other parts.

[shovelhead]

Well, pondering this a little further.  Why not a split manifold from city water.  One leg to the CL city water port.  The other leg to the portable tankless system with the out from the tankless going to the anode rod input of the CL hot water tank? You would need to shut off the cold water input to the CL water heater.  But with this layout you would have cold water and basically a tankless system....   I know .. hair brain.

[charliem]

[font size="3"]Shovelhead,

Most on-demand heaters I've seen are limited as to flow rate and temperature rise, especially small portable units. This is simple physics due to the available heat source. However, it sounds like you want to use your existing portable heater. If you're satisfied with the available temperature and flow rate from your unit, here some additional hookup ideas.

The on board shower supply lines are accessible below the trailer. See my  diagram [a href="http://livinlite.proboards.com/thread/674/21rbs-fresh-water-schematic"]http://livinlite-owners.com/thread/674/21rbs-fresh-water-schematic[/a]  One option is to put a Y valve in the line feeding the hot side of the shower.[/font][font size="3"] This would allow you to select between the on board heater or the portable unit to feed the shower. If you set the portable hotter than is comfortable you could adjust the shower temperature with the shower cold water knob. Connect the portable heater water input to the CG water supply as you describe in you post.

Same approach, but put the Y valve in the shower cold line. You then set the portable cooler than desired and mix hotter water from the on board heater.

Option 3: connect the portable output to the hot water drain valve under the rear of the trailer and feed the whole hot water system. You would have to turn off either the on board heater's cold input or hot output. Feed the portable in parallel from the CG as you described. The advantage here is no pipe cutting or new valves required, just some remembering to set some existing valves.

Option 4: similar to Opt. 3, but connect to the trailer cold water drain. This feeds the entire trailer, hot and cold, from the portable unit. Leave the on board WH set for normal operation. The portable is then acting as a pre-heater for the entire trailer. Just turn off the portable when you're not using the shower. Advantage: no valves to add or switch. Trailer water system works normally and you can adjust the shower temperature as you normally would. Just hook the portable to CG water and the preheated  output to the cold water drain valve. Only issue might be whether the portable unit can physically support the flow rate.

BTW Atwood makes on demand heaters in the 45K-50K BTU range to directly replace the existing on board heater, but they're $$$$.
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[shovelhead]

Thanks Charlie for the other options.... I'm just thinking out loud.   Biggest reason was the co$t of the Atwood  and the installation.  I'm not able to make the conversion myself.  I see a few alternatives to Atwood but in general they are all pricey.

[charliem]

[font size="3"]Biggest question I have is will your portable support the required flow rate. Do I understand that you have a unit and it can give you a satisfactory shower?  If so I like the last option, using the portable to preheat the entire trailer. The pipes exist with no additions required. Just add a fitting and hook up. All the trailer piping, hot and cold, is PEX and will withstand the temperature. The reservation I had with your original scheme is the trailer CG water connection. There is a short hose from the water connector to the trailer cold side that is not PEX. I don't know what its temp specs are.
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[shovelhead]

Yes the tankless heater provides shower without a problem.  That being said I've only used it a few times at 3 campsites.  I can see where a site without sufficient water pressure would cause a problem.   I'm leaning to option #3.  Hey if supplying pre heated water to the CL doesnt work I still have the outdoor shower.

[whoofit]

My wife likes a long shower. We are adding the Hot Rod electric heating element, in place of the sacrificial anode, to aid in recovery. Might not be fast enough for your needs though at only 480 watts.

[charliem]

[quote source="/post/7863/thread" author="@shovelhead" timestamp="1426460416"]Yes the tankless heater provides shower without a problem.  That being said I've only used it a few times at 3 campsites.  I can see where a site without sufficient water pressure would cause a problem.   I'm leaning to option #3.  Hey if supplying pre heated water to the CL doesnt work I still have the outdoor shower.[/quote][font size="3"]Option 3 should work fine. However, option 4 would let you use the 6 gallons in the WH in addition to the preheated water. Just a teeny bit easier to hook up too. I don't think CG water pressure will be a problem. The shower head will limit the flow to less than 2 g/m. I just don't know what flow limiters might be in your portable heater.
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[charliem]

[quote source="/post/7867/thread" timestamp="1426462567" author="@whoofit"]My wife likes a long shower. We are adding the Hot Rod electric heating element, in place of the sacrificial anode, to aid in recovery. Might not be fast enough for your needs though at only 480 watts.[/quote][font size="3"]The factory heating element is 1500 watts. I measured recovery time from 77F water at about 20 minutes on gas alone. Adding the 1500 watt electric element cut it to 14 minutes. The 480 watt element will do little for recovery time, but will allow you to run on electric alone if you plan ahead. [/font]

[jerrybeaird]

Would this help out for a long shower?  I read about it but don't know anyone with one and it is a gas only unit, which I see is the only downside.

[a href=""]www.truma.net/us/en/press-events/truma-aqua-go.php[/a]

[shovelhead]

[quote source="/post/7884/thread" timestamp="1426470858" author="@nd1979"]Would this help out for a long shower?  I read about it but don't know anyone with one and it is a gas only unit, which I see is the only downside.

[a href=""]www.truma.net/us/en/press-events/truma-aqua-go.php[/a]
[/quote]I've seen their claims, been to the website.  It looks good but how much is marketing hype?  I've not seen any reports from actual owners nor a street price.......

[funpilot]

[quote source="/post/7918/thread" timestamp="1426528444" author="@shovelhead"]

Would this help out for a long shower?  I read about it but don't know anyone with one and it is a gas only unit, which I see is the only downside.

[a href=""]www.truma.net/us/en/press-events/truma-aqua-go.php[/a]

I've seen their claims, been to the website.  It looks good but how much is marketing hype?  I've not seen any reports from actual owners nor a street price.......
[/quote]Well, looks like I have decided to get the Truma AquaGo Comfort model installed in my trailer.  I have not seen any owners who have paid for the unit post on any forums yet, so I may be one of the first out there ...   I am using a new Truma certified dealer not far from where I live that is located in the Outer Banks, NC to do the work.  He has also offered me a fair price for my basically unused existing hot water heater.   Will let you know if the DW likes it as that will be the ultimate test.

[shovelhead]

OK Funpilot... keep us posted.  I want long hot showers.  Seems the only little relief I get from arthritis.  I was really thinking of one of those blow up portable spa's   

[funpilot]

[p]Here is link to another approach to get hot water on another forum to consider.[/p][p]
[/p][p][a href="http://www.rvforum.net/SMF_forum/index.php/topic,82975.msg751446.html#msg751446"]http://www.rvforum.net/SMF_forum/index.php/topic,82975.msg751446.html#msg751446[/a][/p][p]
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