Water Heater replacement

[Floridastorm]

Looking to replace the water heater on my 2002 Born Free 24 RB motorhome. it's actually the original water heater 20 years old. It still works intermittantly but takes forever to produce hot water and I think only heats about 2- 3 gallons at a time. Believe it's a Suburban or Atwood model. Will replace it with a tankless electric-Propane unit. There is just the two of us and we would be boondocking only enroute to and from an RV park and for day trips outside of the RV park. So showering and doing dishes would be done in the RV park.

What I need to know is how many BTUs do I need and how many gallons per minute flow rate? The heaters like Furrion seem like overkill at 60,000 BTUs and the Excel at 38,000 BTUs I'm not sure about as it's a pretty new model.
Any and all assistance will be greatly appreciated. The Furnace is also not producing heat, just blowing air. But, we live in north central Florida and have a heating element in our AC unit that does just fine.



Dave - 82 yesterday and still kicking

[K7JV]

Hi, Dave. An on-demand water heater would require a pretty high BTU rating, as it has to be able to fully heat the water as you are using it. A standard water heater can take its time re-heating the water, so the BTU rating can be much lower. The water heaters for the RV that Atwood or Furrion or Suburban would produce would be designed to serve normal RV demands, so if you look at what's generally available, you should be good.

I will share that on-demand water heaters aren't for everyone. I was super happy when I found that our new Entegra Esteem motorhome had the on-demand water heater option. But I would never do that again. But that's just our thinking. Especially when boon-docking, they can waste a lot of water, as the delivery of hot water to the point you need it takes a while. For our shower it took about 45 seconds at full flow to have water we would be able to step into. All that 45 seconds of unusable water had to be pumped from the fresh tank and passed straight thru the shower drain to the gray tank with zero benefit. We're probably talking several quarts, at least. While not a lot, when boon-docking it adds up. Do your research, though. There are after-market options that can be added, generally in your shower, that can minimize or eliminate that water waste issue.

It is really nice to have "unlimited" hot water. But Angie's and my hot water requirements do not exceed what a standard tank-type water heater can deliver.

Also, tankless water heaters require special attention when winterizing. But in N FL you shouldn't have any issues with that. Tankless water heaters aren't a great idea when hard freezing conditions are encountered. We were at our daughter's home in San Antonio for Christmas, and it got really cold! I am talking about a low one morning of 12°. Their next door neighbors were away for the holidays. We saw water pouring out of the next door neighbor's pool-house wall. On investigation, we found that the tankless water heater had frozen and ruptured. That's going to be an expensive repair for them when they get home. They had family in the area that was able to turn off the water to the pool house for them. Tankless water heaters do not produce any heat when hot water is not being used, so they are very vulnerable to freezing conditions. For that same reason, just using air to evacuate the system for winter conditions is not sufficient. Anti-freeze must be used to winterize any tankless systems like you are looking at, or even the wonderful AquaHot and HydroHot systems in the "Class A's"

Just some thoughts. Also, you might see how much electric heat capability you have in those heat strips in your roof unit(s). If you are talking about having your coach in winter conditions in the NE, you will probably need several kW of heating to keep comfortable. And, those strips will not heat your "belly" where a lot of your vulnerable plumbing is located like the coach's furnace system is designed to do. So take that into consideration so you don't have freezing issues in the belly. We live in the NW, and winter RV'ing is a whole new baby, for sure!!! Our Esteem can not do it, as designed, as it has a lot of exposed fresh, gray and black water systems that are not insulated under the coach, so it is a "fair weather" coach, period.

[Floridastorm]

Originally Posted by K7JV

Hi, Dave. An on-demand water heater would require a pretty high BTU rating, as it has to be able to fully heat the water as you are using it. A standard water heater can take its time re-heating the water, so the BTU rating can be much lower. The water heaters for the RV that Atwood or Furrion or Suburban would produce would be designed to serve normal RV demands, so if you look at what's generally available, you should be good.

I will share that on-demand water heaters aren't for everyone. I was super happy when I found that our new Entegra Esteem motorhome had the on-demand water heater option. But I would never do that again. But that's just our thinking. Especially when boon-docking, they can waste a lot of water, as the delivery of hot water to the point you need it takes a while. For our shower it took about 45 seconds at full flow to have water we would be able to step into. All that 45 seconds of unusable water had to be pumped from the fresh tank and passed straight thru the shower drain to the gray tank with zero benefit. We're probably talking several quarts, at least. While not a lot, when boon-docking it adds up. Do your research, though. There are after-market options that can be added, generally in your shower, that can minimize or eliminate that water waste issue.

It is really nice to have "unlimited" hot water. But Angie's and my hot water requirements do not exceed what a standard tank-type water heater can deliver.

Also, tankless water heaters require special attention when winterizing. But in N FL you shouldn't have any issues with that. Tankless water heaters aren't a great idea when hard freezing conditions are encountered. We were at our daughter's home in San Antonio for Christmas, and it got really cold! I am talking about a low one morning of 12°. Their next door neighbors were away for the holidays. We saw water pouring out of the next door neighbor's pool-house wall. On investigation, we found that the tankless water heater had frozen and ruptured. That's going to be an expensive repair for them when they get home. They had family in the area that was able to turn off the water to the pool house for them. Tankless water heaters do not produce any heat when hot water is not being used, so they are very vulnerable to freezing conditions. For that same reason, just using air to evacuate the system for winter conditions is not sufficient. Anti-freeze must be used to winterize any tankless systems like you are looking at, or even the wonderful AquaHot and HydroHot systems in the "Class A's"

Just some thoughts. Also, you might see how much electric heat capability you have in those heat strips in your roof unit(s). If you are talking about having your coach in winter conditions in the NE, you will probably need several kW of heating to keep comfortable. And, those strips will not heat your "belly" where a lot of your vulnerable plumbing is located like the coach's furnace system is designed to do. So take that into consideration so you don't have freezing issues in the belly. We live in the NW, and winter RV'ing is a whole new baby, for sure!!! Our Esteem can not do it, as designed, as it has a lot of exposed fresh, gray and black water systems that are not insulated under the coach, so it is a "fair weather" coach, period.

Wow, some great information. I'm not sure what the difference is between a tankless electric-propane water heater and a standard water heater like the Suburban, Atwood, and Furrion. Don't those models us electricty and propane or is the method not the same. Can you assist me with explaining the difference? We live in north central Florida just above the frost free line which runs east to west across the top of Tampa and Orlando. That means that we may get one or two days during the year, around Christmas, where we may get a freezing temperature but usually not a hard freeze. We also would never be traveling outside of the sunbelt until Spring. I'm having my mobile technician install a new water heater and he will check out the lack of heat from the furnace at the same time. I admit that I'm not mechanically inclined being a desk jockey my entire career. And, to tell you the truth, at my advanced age I don't think I want to learn how to be mechanically inclined. I am however willing to pay for any repair work or replacement that happens along in order to keep the motorhome in a safe and top shape. Luckily, when I bought it, it was well cared for by the owner and the reason that I searched for a long time for the right Born Free.

[Old-Biscuit]

Tankless water heaters........high btu rating because heat is only ON when water flows so it takes high heat transfer to have hot water but burner only is ON when you have water flowing. Otherwise burner stays off
*tankless typically only have propane burners
AquaHot/Oasis Systems have electric elements and burners (diesel)---they provide HEAT to RV plus hot water

Tank water heaters.......8,000, 10,000 or 12,000btu ratings that heat water in a storage tank that provides hot water when you turn faucet on
Burners are controlled by a set of t-stats and heat the stored water to 130*F/140*F/160*F (brand/model dependent) and reheats that water when temp drops to 100*F/110*F

2002 Born Free........most likely has a 6 gal propane only tank water heater
Which Brand would decide what can be used for replacement as Atwood is different size opening then Suburban used
*Easiest way to tell difference if no LABEL in outside compartment is design of combustion/exhaust 'U' tube
Suburban....stacked 'U' tube ---exhaust directly above combustion
Atwood.......diagonal 'U' tube ---exhaust is top left/combustion is bottom right

[K7JV]

OldBiscuit's information and thoughts are always spot on! He is a wealth of information on the details relating to a ton of "stuff" used in the RV industry and I'm frequently very impressed with the knowledge he has to share..

I'm glad your tech will check out your furnace for you. I really do think you will want that working, but if you aren't making your trek until spring becomes a reality, and if you aren't doing much of any RV'ing in sub-freezing conditions, the issues get much smaller.

It takes a lot of energy to heat and/or cool water. You can do it by delivering energy at a very high rate (lots of BTU's per hour or tens of kilowatts of electricity capacity)for a very short time, or you can deliver it at a much lower rate but over a long period of time. Propane can deliver a lot of heat energy in a short time. The burners in the normal type water heater we've all enjoyed for over a century don't deliver nearly as many BTU's per hour as the burner in a tankless unit.

If your career involved math, I'll share a couple of conversion factors that may be interesting. (If not, forget I shared it). First, when you want to compare electric with propane when it comes to heating and cooling, one kilowatt-hour of electric energy is equivalent to 3,412 BTU's. Second, the official definition of a BTU is the amount of heat energy required to heat 1 pound of water one degree Fahrenheit. Those two relationships can help when you want to look at how many degrees you need to heat your water while it is in the water heater (whether you are heating it in the tank and storing it to use later or heating it in coiled tubes that surround the burner chamber to heat it while you are actually using it).

But overall, it sounds to me like you are making great decisions. Enjoy your coach and your travels!

[Sammie2023]

I I have a 1997 snowbird RV I was replacing the water heater from another RV but the wiring is different how do I know which goes where

[Old-Biscuit]

Originally Posted by Sammie2023

I I have a 1997 snowbird RV I was replacing the water heater from another RV but the wiring is different how do I know which goes where

If would be less confusing if you started your own thread concerning your water heaters so that responses do not get mixed in with responses to OPs water heater issue

And please include what Brand/Model of Water heater you are removing and what Brand/Model you have to install
That will help identify wiring ---which is used for what

[K7JV]

Wow, great question. Again, OldBiscuit probably would have the answer on the tip of his fingers, but I surely don't. If I were on my own, I would try to find a model number on both water heaters and then Google the makes and model numbers. For example, in the search bar I might put: "Gutenhot 123-4567 owners manual" where "Gutenhot" is the brand and 123-4567 is the model number. I'm betting you would find hits on both, and both would tell you how any connected wires are fed. Not knowing any more about your project, that is what I would suggest.

[Floridastorm]

I'm thus wondering which type of water heater would be best for the two of us as we are the only ones that will be using this MH. The type that we have now, which is a Suburban, eventually does make hot water but takes a long time and I believe wastes water getting up to temperature if you have to turn on the shower faucet beforehand. Do the newer ones heat up faster and allow you to take a decent shower? We would only be showering when we are in a park hooked up to the facilities and with the grey water hose connected. So, no problem with the grey water waste tank filling up. One other thing, if you will. When hooked up to 120 does the DC battery connect switch have to be turned on in order for the water heater to work or does the converter automatically take care of that? I believe a water heater works off of 12 volts if I'm not mistaken. Hope I am making sense.

[Rockwood27]

You're lucky to have a Suburban WH. Atwood was bought by Dometic and doesn't have a direct replacement, although Suburban does have a clone for the Atwood.

To answer your last question, the 12V side of your RV gets its 12V from two sources. The 1st is from the batteries if the battery switch is turned on and the 2nd is from the converter if plugged into 120V shore power. You can actually get it from both sources at the same time. Therefore, you don't have to have the battery switch on, while connected to shore power.

Sent from my SM-A515U using iRV2 - RV Forum mobile app

[K7JV]

Good morning, Floridastorm!

I no doubt tried to cover too much ground in my earlier responses. Almost all RV water heaters "work" with propane. Many can "work" with 120 VAC electric power. The 12 volt DC connections are strictly for ON/OFF control.

At the location where you turn your water heater ON and OFF, do you have more than one option? It may be a rocker type switch with "gas" or "propane" on one side, "OFF" in the middle and "AC" on the other? It may just be one switch, in which case is is likely "gas" only. It may be two switches where there is one for "AC" and one for "gas".

If you operate your water heater on propane, it should not take long to come up to full temperature. I would expect it to take less than a half hour. If you do it on AC only, it is going to take a lot longer for it to get hot. If you have the option and choose BOTH "gas" and "AC" it will come up to temperature even faster.

A conventional water heater like the Suburban, Dometic or Atwood does NOT waste a drop of water in the heating process. From a water use standpoint, they are very efficient. From an energy use standpoint, operating them on "AC" only is extremely efficient, as well. But it's a lot slower.

I hope that helps a little. You should have options and it should give you good performance, as far as RV water heaters go. NOTE: My comments above are for the decades-old tank type technology. Tankless on-demand water heaters are a different animal, as discussed at some length earlier.

[K7JV]

Regarding part of your original post, the choice of tankless (on-demand) or conventional tank type water heaters, that is totally YOUR choice. From what I've experienced, we would choose a conventional water heater over a tankless unit. They're reliable and they work. They're not as energy efficient, but they're not all that bad, either. (It would be interesting to know how much propane is used in, let's say, a 24 hour period to keep a conventional water heater's contents up to temperature if there is zero use for the entire time. Avoiding that heat loss represents the only real efficiency benefit to going tankless). I'm sure that many will be very happy with the tankless, if they choose to go that way, and to say which is truly "best" really depends on how the hot water is used.

[Old-Biscuit]

2002 Vintage RV and Suburban Water Heater......
Suspect it is 'GAS' only
Gas (propane) will heat water at a rate of 10 gal/hr from initial fill temp of 70*F
So first heat cycle could take 20 minutes...but once up to t-stat control it should only take 10 minutes
Provided....LP System Pressure is correct and orifice/burner/combustion-exhaust chambers are Clean
*Have you done any routine maintenance, have you drained/flushed it & replaced anode rod routinely, cleaned you the burner assembly etc

AS for replace........a Suburban SW6D would be direct replacement
Gas Only but ALL NEW


Here is copy of the Suburban Water Heater Master Manual
Covers ALL models
https://techsupport.pdxrvwholesale.c...ing-Manual.pdf

[Floridastorm]

Originally Posted by K7JV

Good morning, Floridastorm!

I no doubt tried to cover too much ground in my earlier responses. Almost all RV water heaters "work" with propane. Many can "work" with 120 VAC electric power. The 12 volt DC connections are strictly for ON/OFF control.

At the location where you turn your water heater ON and OFF, do you have more than one option? It may be a rocker type switch with "gas" or "propane" on one side, "OFF" in the middle and "AC" on the other? It may just be one switch, in which case is is likely "gas" only. It may be two switches where there is one for "AC" and one for "gas".

If you operate your water heater on propane, it should not take long to come up to full temperature. I would expect it to take less than a half hour. If you do it on AC only, it is going to take a lot longer for it to get hot. If you have the option and choose BOTH "gas" and "AC" it will come up to temperature even faster.

A conventional water heater like the Suburban, Dometic or Atwood does NOT waste a drop of water in the heating process. From a water use standpoint, they are very efficient. From an energy use standpoint, operating them on "AC" only is extremely efficient, as well. But it's a lot slower.

I hope that helps a little. You should have options and it should give you good performance, as far as RV water heaters go. NOTE: My comments above are for the decades-old tank type technology. Tankless on-demand water heaters are a different animal, as discussed at some length earlier.

Yes, there is an on /off switch alongside the rear bath sink to ignite the water heater and subequently the propane. It is simply an on or off switch which I imagine is for igniting the the propane burner. Does not have any other option. I would be thinking that the Suburban that I have, which is 20 years old, would only have the ability to heat with propane and not electricity. Maybe the modern water heaters have the ability to heat with propane and/or electricity. I think the main problem, as I see it, with my unit is it seems you have to run the water quite a while to get hot water which would put unecessary water into the holding tank when you are not hooked to a land line unless you can turn on the water heater and wait a few minutes and then turn on the faucet for the shower or kitchen sink.