Okay so my camper has a 30 amp 120v cord powering it from shore power. My existing water heater is a small tank propane water heater that is only good for about a 2 minute shower. I am attempting to cut off my propane completely. Is there anything stopping me from installing a tankless water heater that runs on 50amp 240v power and running a separate power connnection to shore power specifically just for the water heater?
Electric Tankless Water Heater
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John From Detroit
Well-known member
A tankless water heater needs way more than your 30 amp shore cord can supply
In fact it needs abnout 3x or more what your shore cord can supply
What's the wattage
30 amps *120 volt is 3600 watts.. Now small tankless only suck about 10KW (Thousand watts) but the big ones 40 You only have 3.6 Not nearly enough.
a 50 amp cord (at 240 volts) is 1200 So it can power a Tankless. but with next to nothing left over.
In fact it needs abnout 3x or more what your shore cord can supply
What's the wattage
30 amps *120 volt is 3600 watts.. Now small tankless only suck about 10KW (Thousand watts) but the big ones 40 You only have 3.6 Not nearly enough.
a 50 amp cord (at 240 volts) is 1200 So it can power a Tankless. but with next to nothing left over.
Kirk
Well-known member
As far as I know the only thing that might stop you is your electrical knowledge. As a retired electrical tech I have no way to know what your skills are but to do so will require more than just minimal knowledge of electric theory and design. If it were me the answer would be that yes. I could do that but if you ask would I do it the answer is no. Doing that would mean that you won't have any hot water if you do not have a 50a RV outlet available and if the 50a is the only outlet then you would have hot water but nothing else.
I much wiser choice would be to install a larger water heater as you probably have a 6 gallon model and Suburban makes one that is as large as 12 gallons. My other suggestion would be to get one of the water saving shower heads as we can easily take as much as a 10 minute shower from our 6 gallon water heater, using our Oxygenics shower that I installed in about 10 minutes.
Okay, the camper is in a permanent location with both a 30amp 120v and 50amp 240v connection and the service is 100amp so I’m not worried about convenience and also I’m actually a licensed electrician in Alabama. I was just providing the electrical information to let you know I had plenty of power available. In theory I knew it should work, I’m just not super familiar with campers and was wondering if I might be missing something. If having the right electrical available is my only worry then I should be perfectly fine. I will also be installing a small 60 amp fusible disconnect inside the camper just for added safety.
I don’t know if you misread my question or if it was worded wrong but the tankless would have its own power cord completely separate from the rest of the camper. The camper will remain 30amp 120v and I would be running a completely separate power source for the tankless
NY_Dutch
Well-known member
In your situation, what you propose would work fine. Go for it...
Mark_K5LXP
Well-known member
I looked into tankless for my home and dismissed it as too problematic. The electric ones, even 240V 5kW jobs have limited flow for useful temperature rise. If you're only getting a 2 minute shower there's something wrong with your plumbing. Even a 6gal RV heater has enough ~160F water in it to mix with cold for at least a 10 minute 1.5GPM 110F shower.
Mark B.
Albuquerque, NM
Mark B.
Albuquerque, NM
Gary RV_Wizard
Site Team
The short answer is No, nothing to stop you. The wisdom of doing so is a different question, which others have already addressed.
Is your present heater gas/electric, or gas only? You could eliminate propane by installing the same style tank heater that has 120v electric heat, but you would probably still want a separate power supply for it. The 30A/120v main power to your RV simply isn't enough to do everything via electric power.
The tankless heater makers like to tout endless hot water, but reports from those who install them in RVs usually say they fall well short of that. But you are talking about a 240v, high amp model, so it should perform better.
I also wonder if you have a problem with your existing heater. A 6 gallon heater should be able to deliver 3-4 minutes of 115 degree water to the shower head. It might, though, begin to cool off a bit toward the end of that period. Depending on the age of your heater, it will have either a 130 or 140 degree thermostat. A few models (e.g. the Atwood XT series) actually heat water to 160, but then blend that with cold water so that the output is still about 140, but that only increases the quantity of the delivered hot water. But since your goal is to eliminate propane altogether, this may be moot.
Is your present heater gas/electric, or gas only? You could eliminate propane by installing the same style tank heater that has 120v electric heat, but you would probably still want a separate power supply for it. The 30A/120v main power to your RV simply isn't enough to do everything via electric power.
The tankless heater makers like to tout endless hot water, but reports from those who install them in RVs usually say they fall well short of that. But you are talking about a 240v, high amp model, so it should perform better.
I also wonder if you have a problem with your existing heater. A 6 gallon heater should be able to deliver 3-4 minutes of 115 degree water to the shower head. It might, though, begin to cool off a bit toward the end of that period. Depending on the age of your heater, it will have either a 130 or 140 degree thermostat. A few models (e.g. the Atwood XT series) actually heat water to 160, but then blend that with cold water so that the output is still about 140, but that only increases the quantity of the delivered hot water. But since your goal is to eliminate propane altogether, this may be moot.
Tom
Administrator
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I can't help much with your existing gas water heater. But, as someone who installed numerous tankless water heaters in homes in the olde country(domestic electric service was 240V, single phase) starting back in the 70's, I'd say go for it. Your 240V/100A service should eliminate the concern folks have about 'insufficient power', but you already knew that.
I’ve also thought about the other options, but if I’m going to be running a new power line anyway I figured I might as well go with a tankless big enough that I know will be good. The existing is propane only and I don’t know much about camper water heaters like I said before but there is a pipe connecting the hot and cold water together right next to the water heater so I’m assuming it’s the 160 degree that mixes the water like you’re talking about. It may have issues or be plumbed wrong but I plan on eliminating that with the tankless and taking the cold to cold connection and hot to hot without any pipes in between. I’m no plumber but feel comfortable working with pex as I’ve done small pex jobs in the past. I am trying to eliminate propane as I said though. The reason I chose not to go with a tank electric water heater is the existing water heater is in a very small cabinet space with no room for putting in a larger tank and I really don’t want to be tearing out cabinets. With the tankless I don’t have to worry about space
Sounds like you have a problem with the tank heater you currently have.
As for "The tankless heater makers like to tout endless hot water, but reports from those who install them in RVs usually say they fall well short of that." I installed a low end EccoTemp L5 tankless propane water heater that had been used on another project in my daughter's truck camper. We put a typical low flow RV hand held shower head on the heater. We both used it, even washed our hair, and it worked just fine. I hung it on the wall inside the bathroom area. There is a roof vent in the bathroom area so I just let the thing vent naturally. Heats up the bathroom while we are showering which is a plus for us. Works beautifully. We do take shortish showers due to the small size of the holding tanks in the camper. Except when we are on full hookup. That means a long, hot shower. Really happy with the little old Eccotemp L5.
As for "The tankless heater makers like to tout endless hot water, but reports from those who install them in RVs usually say they fall well short of that." I installed a low end EccoTemp L5 tankless propane water heater that had been used on another project in my daughter's truck camper. We put a typical low flow RV hand held shower head on the heater. We both used it, even washed our hair, and it worked just fine. I hung it on the wall inside the bathroom area. There is a roof vent in the bathroom area so I just let the thing vent naturally. Heats up the bathroom while we are showering which is a plus for us. Works beautifully. We do take shortish showers due to the small size of the holding tanks in the camper. Except when we are on full hookup. That means a long, hot shower. Really happy with the little old Eccotemp L5.
Kirk
Well-known member
Knowing that you understand electricity makes a big difference to me. As one who made a career working with electricity and who knew one of those that lost their life to a mistake working with it, I try to give advice partly based upon who the advice is being given to. I have done many repairs to equipment caused by amateur electricians. If I were you I would then run new Romex from the location of the new water heater to the area of the present distribution box and power cord and install a new box for the 240V supply with at least a circuit breaker for it, then the new cord to your outlet. You may also consider relocation of the water heater to give it as short a distance to the shower as possible since the line between the two will be full of cold water. As long as you are not moving the RV at all and resale is of no concern, then there isn't any problem but you should probably also check with the park management to be sure that they won't object.
John From Detroit
Well-known member
Ok well in that case it MIGHT work.. However I spent a few years with a blown engine sitting on a 50 amp site on what may well be the only PROPERLY wired campground in the USA.. Every site fed back to the main distribution panel. There was no "Daisy Chain" every site had it's own 50 amp ganged breake.. You park there you only get 50 amps Oh you can plug in 1-2-3 or 4 courds (50/30/15/15) But you only get 12000 watts. no more.. then CLICK and you need the manager's key to reset that breaker.
Tom
Administrator
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Good approach.
How do you define "amateur electricians"?
Good advice.
Gary RV_Wizard
Site Team
Probably not. What you are seeing is the winterizing bypass plumbing, which allows you to shunt the cold water feed to the heater directly to the heater output (hot) side. It's used when using antifreeze in the plumbing for winter storage.
Now that you say that I do see a bypass valve, I had no idea but that is cool to know
I guess I will leave that in place even with the tankless so it could still be used if needed
CharlesinGA
Well-known member
The Rheem heaters in this brochure cover the whole spectrum of amp draws and water heating capability. The 11Kw model is capable of raising the water temp 50°F at a flow rate limited to 1.5 gpm flow. That means your incoming water temp needs to be about 60°F in order to have a comfortable shower, and you need to be sure and have a shower head that limits flow to no more than 1.5gpm.
Story time......... a number of years ago a friend of mine had inherited and was living on a small farm, and also had inherited a very old house and property in town a couple of miles away. It came to the point where she could not continue to pay taxes on both properties so she put them up for sale, and planned on keeping whichever didn't sell. The farm, which she had invested in new thermo pane windows, insulation, a deep well, gas instant water heater, etc, sold first. So the plan was to fix up the 150 year old house in town. It had good wiring, as it had been professionally rewired several years before. The plumbing was a mess and no one would take on the job, so I ended up with it. Working when I had time, I worked on getting the bathroom plumbed while another guy built a nice shower. For hot water I had selected a Rheem 11Kw unit and mounted it on a board hanging from the floor joists. I plumbed it so when done and a whole house instant water heater was installed, all I had to do was close two valves and cut the pipes. This water heater put out piping hot water in the bathroom sink at full flow and while later she went on how she told me the shower was too cold all along, this was only after the whole house unit was installed. It turns out the single handle shower valve had an adjustable stop and it was stopping the handle from going far enough warm, so after she made an issue of it, I adjusted that.
But the point of all of this is the 11Kw water heater did just fine. This is the largest heater you will be able to operate on a true, 50 amp circuit however.
As John noted above, if you are in an RV park, its quite possible that the pedestal is being supplied with ONLY 50 amps and when you run the water heater, and are also drawing from the 30 amp, something up line may blow. Its also possible that the RV park may not allow but one connection to the pedestal. Its much the same as there not being 800 amps of power in a panel because you have 40 twenty amp breakers, your main will only be 200 amps. That pedestal may have a 50 amp somewhere else in the park feeding it, and possibly several other sites, so beware.
Charles
Story time......... a number of years ago a friend of mine had inherited and was living on a small farm, and also had inherited a very old house and property in town a couple of miles away. It came to the point where she could not continue to pay taxes on both properties so she put them up for sale, and planned on keeping whichever didn't sell. The farm, which she had invested in new thermo pane windows, insulation, a deep well, gas instant water heater, etc, sold first. So the plan was to fix up the 150 year old house in town. It had good wiring, as it had been professionally rewired several years before. The plumbing was a mess and no one would take on the job, so I ended up with it. Working when I had time, I worked on getting the bathroom plumbed while another guy built a nice shower. For hot water I had selected a Rheem 11Kw unit and mounted it on a board hanging from the floor joists. I plumbed it so when done and a whole house instant water heater was installed, all I had to do was close two valves and cut the pipes. This water heater put out piping hot water in the bathroom sink at full flow and while later she went on how she told me the shower was too cold all along, this was only after the whole house unit was installed. It turns out the single handle shower valve had an adjustable stop and it was stopping the handle from going far enough warm, so after she made an issue of it, I adjusted that.
But the point of all of this is the 11Kw water heater did just fine. This is the largest heater you will be able to operate on a true, 50 amp circuit however.
As John noted above, if you are in an RV park, its quite possible that the pedestal is being supplied with ONLY 50 amps and when you run the water heater, and are also drawing from the 30 amp, something up line may blow. Its also possible that the RV park may not allow but one connection to the pedestal. Its much the same as there not being 800 amps of power in a panel because you have 40 twenty amp breakers, your main will only be 200 amps. That pedestal may have a 50 amp somewhere else in the park feeding it, and possibly several other sites, so beware.
Charles
Fogattiliving
New member
Yes, you can install a tankless water heater that runs on 50 amp 240v power and run a separate power connection to shore power specifically for the water heater. This setup would allow you to cut off propane usage and provide a more efficient and longer-lasting source of hot water for your camper.
