Tankless hot water heater

[Michael.shafer]

I did some searching through the forum and I didn't see, or just not smart enough, to get information on tankless water heaters.

I'm trying to figure out if it's worthwhile to do so and what is the better brand to go with. There are so many options especially on Amazon.

We have a 2018 374fl and we're looking at doing some long term trips for my wife's work and the one thing she would like to have available is a longer shower during the winter.

I appreciate the help.

[goingwest]

You can run present gas - electric water heater on gas & electric at the same time and have endless hot water.

[Mikendebbie]

Below is a post I made on the Keystone Owners Forum this past February.
If you plan to dry-camp...you probably should not have an on-demand water heater (my opinion). We never dry-camp. Also - Suburban produced a "circulating" unit a few years ago, and those have not worked well (based on forum postings). I don't think you can even buy those anymore.
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I have a Suburban IW60 tankless water heater in our unit and we really like having endless hot water.

You should do your own research on various models...lots of youtube reviews and installation guides.
Girard
Fogatti
Furrion
Suburban
Truma

My observations...Girard, Fogatti, Suburban, Furrion generally cost ~$600 for the unit and you can install them...it is not a very difficult job.

The Truma costs ~$1200-$1300 for the unit and they require installation be performed by Truma certified installer. I would guess the installation cost to be based on 4 hours x RV Tech hourly rate $150??? (purely my guess).

As you do your research on various models - pay attention to the BTUs produced by each and the required annual maintenance/ descaling proceedure. I assume the BTU rating is related to how quickly the flowing water can be heated. The IW60 is a 60,000 BTU unit. My IW60 does not have descaling hookups built in. I still need to add those valves and connections which I can buy the pieces and parts at Home Depot. The Truma has a built-in descaling process to perform annually (nice!). I can not speak to the descaling requirements for the other models. The pic below shows the decaling piping for my IW60. Basically - I will pump descaling solution (vinegar?) circulating thru the internal heater pipes for an hour or so. I need to add valves to keep the solution from running into the RV piping system. The pump and the 5 gal bucket of solution sit out side the RV, and I will hook up to new connections I install in the basement. The pump can be a 12 volt pump or a 110 v pump - whatever your preference. I figure the descaling stuff will cost me between $200 - $300 to purchase...the pump is the largest part of that cost.

The Truma has a small heating/surge tank built in. The water can be kept hot in the tank so that when you turn on hot water - you quickly get the heated water from the surge tank. On my Suburban - you turn the water on and you wait 10-15 seconds for the hot water to get delivered to your shower or faucet. The Suburban does not "turn-on" until it senses water flow. We set out water temp to 130* (the maximum) and temper with cold as needed at the faucet. In our unit the heated water temps are affected by the temperature of the water coming out of the ground from the City outlet. The colder the water supply is - the temp at the outlet will be less than the desired 130*. I can't speak to this issue for the other models. I turn on the shower and stand outside while I wait for the hot water + get it regulated to suit me - then step in. I skip the "blast of cold water" others have experienced. Also - we do not boondock - ever! I am always hooked up to 50 amp campground power. I can not speak to how well these things are suited for boondocking.

The second screen shot is from a post I did on the Montana Owners Forum showing actual temps of my heated water at each faucet/outlet.

Here are links to other forum discussions on the subject.

https://www.montanaowners.com/forums...ad.php?t=85412
https://www.montanaowners.com/forums...ad.php?t=86790

[Bourbon County]

I've tried twice to make a lengthy post and keep getting kicked off. I'll try a couple of shorter versions.

With any tankless water heater, the biggest factor to consider is the GPM delivery. The advertised spec is normally based on an average groundwater temperature and may not be applicable for your situation. Groundwater (utility) temps vary greatly geographically, ranging from the low 70s in the deep south to low 40s in northern tier states. There are a number of online maps to view where you plan to camp. If you have to raise water temperature by 90 degrees as opposed to 60 degrees it will take more time and fuel. I'm not highly versed in RV models, but the residential models all have flow regulators that will throttle the flow rate down to keep the temp constant, I would imagine the RV models do the same.

[Bourbon County]

Once you estimate the groundwater temps in the area(s) you will be camping, there are some more tests you can do to determine how much you need.

Fist of all, have your wife adjust shower water to a temperature she is comfortable with, use a BBQ thermometer and measure and record that temperature. Most people find 100 degree water comfortable. Secondly, put an empty 5 gallon bucket in your shower, using a stopwatch, time how long it takes to fill the bucket. This will allow you to determine the actual GPM you shower head will deliver; cold water is fine for this test. The last thing is to time how many minutes your wife actually runs the shower, include the entire time the water is running even the warm up. For several reasons this might be best done without her knowledge.

You should now have all the information you need to determine what size tankless you need. To be accurate, you need to go to the manufacturer's site and look at the delivery curve based on the temperatures you came up with, not just an average.

[Bourbon County]

Another consideration is fuel usage. In an RV you have a finite amount of fuel and you mentioned winter camping. You need to factor in fuel usage for your furnace as well as cooktop/oven, and grill connected to your onboard supply. The tankless heaters have big burners in the 42-60K BTU range; to put that in perspective, your furnace is likely a 40K BTU size burner. Obviously the tankless is only using fuel while it's burning, but if you do the experiments you can calculate how long it's going to be running during a typical day. With both tanks full, your furnace can run for about 32 hours; that's actual run time not total elapsed time. Anything else you run off the LP will only shorten that time. You will need to keep close tabs on your tank levels. LP pricing is all over the place and to be kind the campgrounds that have LP seem to be "opportunistic" with their pricing.

[Bourbon County]

As Mike mentioned, the tankless models require some maintenance. You have no idea on water hardness in the areas you might be camping. A small amount of scaling on a tankless heat exchanger will greatly reduce it's efficiency, they do need flushing periodically. There are "limeblaster" filter elements on the market that fit into a standard housing, I can't speak to their efficacy. If space permits, you could install one of these in the cold water line ahead of the tankless.

Even though they are tankless, there is still a small amount of water that stays in the heat exchanger and onboard piping. Since it's exposed to the outdoor elements and can go for extended amounts of time between usage, it does present a freeze potential. I believe all the models I've researched have a small electric heater just for freeze protection. This feature is an absolute must for any cold weather camping.

I'm not trying to talk you out of this option, just wanted to point out the considerations.

[Bourbon County]

In Mike's post he mentioned how quickly the hot water arrives at the tap. In either system, tank or tankless, there is a quantity of water standing in the piping between the water heater and faucet referred to as the "slug". If this quantity of water has cooled to ambient temperature, it has to be displaced with hot water. Tankless models typically have a timer usually between 3-5 seconds delay on firing the burner after flow is sensed. This is built in to save some fuel and prevent short cycling if someone habitually rinses a coffee mug or such under hot water. After this built in delay, it has to go through the ignition process and heat the heat exchanger up to operating temperature. There will be a longer delay between turning the faucet on and actually getting hot water than on a tank model.

The unit in my home has the surge tank like the RV model Mike mentioned, it's 2 gallons I believe. The idea of a surge tank is to provide hot water while the tankless is going through it's ignition and preheat process and deliver usable hot water quicker. My question for an RV model would be the physical size constraints, I can't imagine that tank could be large enough to hold very much water. My home unit is at least 5X physically larger than what can go into an RV. Of course in an RV all the piping is 1/2" and it's usually a very short distance from water heater to the shower.

If this turns out to be the model you choose, fine. I don't think I would make it a priority on making the decision, don't see it as being a big deal just to wait a few seconds on the hot water.

In my experience, the residential models are actually pretty easy to work on. Everything is modular, just tight places to get your hands into. Some needle nose pliers maybe some hemostats can be extremely handy.

[Carl n Susan]

Originally Posted by Bourbon County;1275731...

I've tried twice to make a lengthy post and keep getting kicked off.....

The usual cause for being kicked out is *NOT* checking the "Remember Me" box on the logon screen. I stay logged on for weeks at a time by clicking that box.

[Mikendebbie]

A few more notes and opinions on tankless water heaters…

Tankless units for RVs are 12 volt units. The flame sparker runs off the battery. They are sort of “cube shaped” to fit the typical water heater space in an RV. They exhaust to the outside like a standard RV water heater or RV furnace. Residential units run off of 110 volt power. They are typically shaped like a suitcase mounted to a wall and would be very difficult to adapt and mount anywhere in an RV. I have never witnessed one running, but I assume they have an exhaust flue vented thru the roof of the house. Basically - they won’t work for an RV.

Motor homes have a different type of on-demand water heater/ coach heater that runs off of propane or diesel. I think one brand is called Aqua Hot. They circulate heated “anti-freeze” thru pipes in the coach to provide uniform heat, and the boiler heats water for the sinks and shower. I think they cost $7000 - $10,000. They are discussed extensively on the IRV2 forum…and that’s about all I know about those.

I think it’s a fair statement to say that tankless propane RV water heaters are not popular in the RV forums. Lots of statements like “I would not want one of those things”. You will find very few threads praising them. You will find very few threads about repairing them. I can’t draw a conclusion for what that says about these water heaters. Topics on slide outs, tires, refrigerators, air conditioners, brakes, black tanks…you can find thousands of threads with problems, opinions and help. I have had good luck with my IW60 and we like it.

During the COVID lock down our RV sat at home for 20 months. A spider made a home in the intake jet (I think?? don’t quote me!). It would not fire up and I failed to find the ONE YouTube video that would have helped me clear the web. We were getting ready to take our first extended vacation in 2 years and I started going thru checking everything like normal a couple of weeks before our planned departure. DW said I AM NOT GOING if we don’t have hot water. I ordered and installed a new IW60 and put the “spider house” in the box. Later I found THE video to show how and where to clear the spider web…so I now have a spare water heater.

There are hundreds of YouTube videos out there for all makes of these water heaters. Watch as many as you can before pulling the trigger on one. Come back to this thread and update us on your decision and experience.

[Michael.shafer]

Thank you so much for all the information you answered a bunch of questions and given me a lot to think about. If I do decide to do it I'll let you know.

[Drifty1]

We have a Truma unit in our Luxe and we love it. We love the recirculating feature for dry camping as we use very little water as keeps the hot water circuit from getting cold. As for running out of hot water we have not had any issues with this as we are pretty conservative.

[Michael.shafer]

Originally Posted by Drifty1

We have a Truma unit in our Luxe and we love it. We love the recirculating feature for dry camping as we use very little water as keeps the hot water circuit from getting cold. As for running out of hot water we have not had any issues with this as we are pretty conservative.

That is good to know, when looking at models it's nice to hear from people that have them. Thanks for the reply. Everyone on this forum is very helpful and knowledgeable, I think you all knew more about these trailers than the people that engineer and make them.

[Bourbon County]

You got me thinking about a tankless for my unit and have subsequently done some research. I did learn a couple of things; a 12 gallon tank type holds about 100 Lbs of water so it's some extra weight if you travel with it full. I don't think it's enough to make much difference.

I never could find any manufacturer that posted a curve or chart on GPM at a given temperature rise. Precision Temp did post that the modulating burner would burn at 16K BTU at a 26 degree to a max of 55K BTU for an 88 degree temp rise. That works out to about 620 BTU per 1 degree rise. Once again, groundwater temp is key; I think most manufacturers use 55 degrees as a reference, it's a national average. In this case to raise water temp by 65 degrees to 120, it would burn at a little over 40K BTU. This makes me think that the models with 40-42K BTU burners might be a little underfired to keep up.

All of them had a max temperature setting of between 120 and 124 degrees and advertised flow rates of somewhere between 2.4 and 2.9 gallons/minute. If you shower with 100 degree water, you will be mixing with 20-25% cold to get desired temp. The demand on the hot water would be reduced by same amount. If your shower head will actually flow 2.5 GPM, this means the hot water demand would be in the 2.0 GPM range. For a footnote; to sanitize dishes and cookware, a 140 degree water temperature is recommended, but nobody is going to wash/rinse dishes in water any hotter than they can stand to put their hands in. Some of them mentioned that water pressure had to be <65 PSI, so a pressure regulator would be a must.

The ones that published much data said the current draw on the 12 volt system was <3 amps, very little.

The Truma is an impressive product. The thing that stood out to me was the filter, which appears to be more of a screen than an actual filter. Since it's an OEM part you would have to buy theirs when replaced; this normally means lots of $ for a small part.

Drifty1 mentioned an instant hot water system. To have this you have to have a tankless with a surge tank, the hot water piping has to have a recirculation line installed, and a circulation pump. I seriously doubt Keystone has ever even made an RV with that feature and it would be extremely difficult to install. If you look at the Truma website that feature is only available on new units that are OEM or ordered with that feature. The surge tank on your application would get hot water to the shower a little quicker, but only by a few seconds.

[Mikendebbie]

Bourbon Country - forum member ChuckS has posted in the past (on the Keystone Owners Forum) that Keystone did install some recirculating tankless water heaters (Suburban RW60) in some 2020 or 2021 Alpine units, and they did not work very good. Consequently keystone does not offer that water heater any longer. He says the recirc units were discontinued by Suburban. I seem to remember seeing an exploded view of the RW60 and it has a small surge tank and recirc pump. The Alpine plumbing was set up to handle recirculating hot water at each fixture.

For what it’s worth - we leave the temp set to 130* and temper the water as needed.

[miatadoc]

We have a Trim AquaGo in our Cedar Creek Champagne and have been pleased with it. Hot water arrives quickly and is maintained for our needs (we aren't extravagant hot water users). There are also 2 settings for the Truma: Eco mode fires the burner to keep water temp in the mixing vessel at 41*and uses less propane; Comfort mode keeps the mixing vessel temp at 120*. The burner otherwise fires with hot water demand. We haven't found that the unit is a big propane user.

There is a 12V filter with a heating element available to prevent freezing of the mixing vessel, but draining the mixing vessel is a matter of unlatching and pulling the big yellow lever, then sliding the filter out. The lever can be closed with the filter out to prevent accumulation of water in the mixing vessel.

[JAMyers59]

We replaced our 6 gallon Rapid Recovery unit with a Girard "On-Demand" unit and I regret the purchase. Regardless of the units temp setting, we cannot get temperature regulated in the shower. We currently have it set at 110F. Once hot water reached the shower head and the cold is slowly brought up to prevent scalding, the water heater will then shut down.

[Mikendebbie]

JAMeyers - have you called Girard with questions on that issue? I will bet they will want numbers on the flow gpm you are getting from the campground hose bib.

I have a Suburban IW60 in my RV and we have had good luck with it. I have not experienced that issue. Our temp is set to 129* and I can temper it successfully. We have it set to maximum because we have a full tub in the front bath and DW just turns on the hot and lets it run until full. It takes a while to fill but by the time it gets to her desired level the whole tub has cooled down to “real toasty-n-nice”. In the winter she often tops off the fill with boiling water from the stove.

It sounds to me like you do not have enough flow coming in to the RV. In my unit we can’t run the sink hot water and the shower at the same because it reduces the flow. Also - in winter, the city water supply is naturally colder, so we don’t get 129* water coming out of the shower head.

Generally speaking - the on demand water heaters do not get much love on the forums. These heaters are probably not good for folks that like to camp in the boonies. We are always in a full hookup park. You might try posting this issue over on our sister forum - Keystone RV Owners Forum. You might get info from a fellow Girard owner over there. I don’t recall reading any Girard related threads here in the Montana forum, and I have been reading and contributing daily for the past 5 years.

Moderators: is this item worth starting a new thread titled “Girard on demand water heater”?