Hot water heater

Happy New Year to all!Question-
Our aging 15 gallon hot water heater may need to be replaced this year. I have a new Atwood 6 gallon hot water heater I had purchased for our 28' Bayliner which sank in Hurricane Katrina that the first mate will not consider installing due to the reduced capacity.
Other than not heating water with no shore power or gen set running, what are the drawbacks of installing a much cheaper 15 gallon home version on the boat?

Forkliftt wrote:


Other than not heating water with no shore power or gen set running, what are the drawbacks of installing a much cheaper 15 gallon home version on the boat?

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You won't have the heat exchanger with a house hold unit.* The only way you will heat water is via shore power or generator.

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I guess you will have to get one with a 120volt element a lot of the household ones are 220v.* Most people appreciate the free hot water from the engine on the marine unit.

Is your wife just guessing or does she know for a fact(experience) that 6 gallons isn't enough? These hot water heaters get the water SCALDING hot and when mixed with cold water, the mix can go a LONG LONG way. In fact, I have lived with 6 gallon heaters all my boating years and have never ran out of hot water....just my experience.

Good point John,
I have considered seeing how long it takes to run through 15 gallons. The only times we have run out of hot water was when we arrived at a transient slip with guests, everyone showers separately (4) before heading to the restaurant.

I would imagine 4 would do it. Those things get HOT!!!!!

If you have the space, I'd recommend a 15 -20 gal unit designed for a boat, using engine heat as suggested above. The efficiency and holding power of a new unit (Torrid?) this size is amazing. In the PNW, nothing beats a hot shower - our unit will easily service 4 showers with engines off and lots left over for dishes.

Does the home unit run off 110V? If not you'll have to have 220V available. The home unit would work fine, but probably corrode out a lot faster than a marine unit. If the home unit has a sacrificial anode (magnesium) it would last longer.

Keith wrote:

If the home unit has a sacrificial anode (magnesium) it would last longer.

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Baker,* we have a 16 gallon water heater on our charter boat, and it seems to be plenty big enough for showers and dishes.* I do tell our guests that if they shower instead of soak, our water supply will go further, and there will hot water for all. It seems to be more than enough though.

Otherwise, In my entire life, I have never had a water heater fail due to leaks.* I'm aware that some recomend replacement of the anode, but have never done it either at home or on my boats.* I wonder if others do this as a regular maintenance item, or do most folks simply let them go? Our current home water heater is at least 20 years old, and still going strong...........Arctic Traveller

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Arctic Traveller wrote:In my entire life, I have never had a water heater fail due to leaks.* I'm aware that some recomend replacement of the anode, but have never done it either at home or on my boats....* Our current home water heater is at least 20 years old, and still going strong...........Arctic Traveller

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Ditto...ditto & ditto.

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I had a marine water heater tank perforate on me after about 4 years as I recall. Don't know if it had an anode or not, but I never changed one. I chalked that one up as a failure due to a wet cell battery about a foot away. I do change my anode on my Raritan regularly... next time it'll be four years. I posted some pictures of an old one on here somewhere. Here it is again FYI. It is doing it's job.

I thought that mine leaked once but I was wrong. I realized this after I replaced it and still found water under it. Turned out that the fresh water pump, a Paragon Jr., had a slight drip and they were mounted on the same board.

When I thought the tank was leaking several buddies looked at it and confirmed that it was indeed leaking. I should feel bad about this but it is only one incident in my long career of fixing things that did not need fixing.

Doc wrote:

I should feel bad about this but it is only one incident in my long career of fixing things that did not need fixing.

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Don't feel too bad.* Last summer we had an oil leak on one of the generators on the Scorpius.* The bell-housing had oil all over the inside, and the flywheel was throwing oil out the vent screen.* It was pretty clear it was the rear main seal, and the owner confirmed the diagnosis.* It took two days to separate the engine from the gen, replace the seal, and to put it all back together.* Upon start up, I had the same oil leak.* Turns out that the oil pressure sending unit was leaking oil onto the starter, which then funneled the oil to the bell-housing.* Unfortunately, it was impossible to see the sender without moving the generator, so it got missed...............Arctic Traveller

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I recently, well a year or so ago, replaced our corroded out old hot water heat exchanger cylinder with a new Isotherm Basic 43 litre tank, and it is fantastic - we never run out of hot water. It has a 240v element as well, which we briefly plug in at the marina using the charger lead, (which is the only shore power we use, as we don't have AC at all out on the water), and the 30 minutes it takes for us to get ready to go is enough to raise it to about 37 degrees C. Then the engine takes over.* Yes, she was in pretty bad shape, but still worked.....but slowly......

Several years ago, we downsized from 11 gal to 6 gal along with installation of a mixing valve.* No hot water supply issues for 2 persons, and the 1500watt AC heating coil heats the 6 gallons very quickly.

Six gallon has been sufficient for us as well. We are more conservative with our showers when on the boat, and that is the primary reason we get by with such a small heater.

A lot depends on the temperature of the water coming into the heater. For me as a liveaboard, the ice cold water coming in during the winter limits the showers or dishwashing you can do at one time. If the on-board tank water is warmer, that would let you use more.

In the summer, I turn the water heater off, since the water coming from the hose on the dock is about 130 degrees F anyway!

Back when we were building boats I tried to get Allcraft , a local mfg of SS Hw units to install 3 sets of electric heater ports.

2 would be wired s one or both could run 15A at a dock with 50A 240V or 30A 120V.

For the cruisers the 3rd port would be for a 7A 120V element.

Many out of the way lovely places only have marginal 120V (maybe 95V) and a few amps dockside.

Since these are usually at interesting towns the ability to live would be done with a priority relay.

These are in Grangers and allow one circuit to operate , as long as the priority circuit was not using power.

The fridge/freezer AC unit would be in charge , any time the fridge was off , the HW heater could work.

With today's $10.00+ a foot overnight marinas there is usually plenty of power, so the old Load Shedding concept is seldom wired in.

The water heater on my boat has a 220 volt element that was purposly installed by a PO because he felt it would be more durable. I don't know if that's right or not, but it works just fine using 110 volt power.

About 20 years ago I had a small ranch in Arizona that had a 220V hot water tank in the barn's tack room. The line (220V) that serviced the heater was broken, somewhere between the main house and the barn. (A distance of approx 150 yards.) Not wanting to go through the exercise of finding, digging, etc, the break, I just ran the water heater off the barn's 110V and everything was fine. It just took longer to heat the water.

I would get the larger capacity. I have a six gallon on my Grady, which is okay for one shower, and a larger one on the MT, which is much better, but still not great. I think it's a 12. I would go with 15-20 gallons.

Arctic Traveller wrote:*In my entire life, I have never had a water heater fail due to leaks.*


In my previous home, I replaced the water heater five times in twenty three years.* Each one sprung a leak.* These were gas fired 40 gallon heaters, the ones you find at Sears or a home center.* We did have aacid well water.

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Forkliftt wrote:Our aging 15 gallon hot water heater may need to be replaced this year.

Other than not heating water with no shore power or gen set running, what are the drawbacks of installing a much cheaper 15 gallon home version on the boat?

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Why would you need to heat hot water?**

Drawbacks of installing a residential water heater in a boat?* If the boat is gasoline powered, there could be an explosion risk as the thermostat would not be ignition proteced.

When I cruise,*I have hot water from engine heat.* I don't have to be at a marina with shore power connected to have hot water.

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rwidman wrote:

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Why would you need to heat hot water?


Been waiting for that one!

We have a six gallon unit by Indel (sp?) I bought on clearance from Defender. There is always enough hot water for two. When we have guests I run the engine and suggest navy showers. So far so good.

Rob

37' Sedan


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We have three options shore electric, DD 671 coolant and the Webasto boiler** The electric water heater is on a timer set for 4:00 AM to 5:00 AM and 7:00 PM to 8;00 PM which we use the summer, the Webasto Ever Hot is used in the winter and have not use the DD 671 coolant yet.* The electric is 11 gallon but the Webasto will provider hot water until we run out of water.***The Ever Hot also heats the engine room to 65+*degrees.*


-- Edited by Phil Fill on Thursday 13th of January 2011 08:20:59 PM

It's one of the reasons I went gas when I built Tidahapah.
Instant hot water all the time alongside or on the water.
No noise.
Along with gas cook top, instant heat control,*fantastic cooking + BBQ
Can't beat it.
The gen set is then for all the other leckky needs.

Benn

-- Edited by Tidahapah on Friday 14th of January 2011 03:05:10 AM

The usual hassle with a propane heater is taking a shower.

Heat on , heat off , it drives the unit nuts , so sometimes the shower is cold.

The RV folks have the same hassles.

The simplest solution is a high in the shower stand pipe that drains back into a FW tank.

The shower is temperature adjusted and the portable end is stuck into the return.
Some pumping electric and some propane is "lost " , but it does save fresh water and makes a shower a delight.

FF,
Heat on heat off is never a problem.
Mixers on all taps and the temp is set and the gas is regulated at a steady flow to maintain the set temp.
never a problem in the 16 years I have been using this system.
Still on the original hot water heater and I have lived aboard most of that time.

Benn

Stupid question. Has anyone ever put a meter across heating element on a 220v heater to see how much is actually on each element? Is there a chance that it is actually 120 volts.

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LarryW wrote:Is there a chance that it is actually 120 volts. .

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If it's a 120V element, sure.

Otherwise it's 220ish in the U.S. Various other volts elswhere.

Here's a link to show how a domestic heater can be wired. Read down the page beyond the "off peak" setup.

http://waterheatertimer.org/How-to-wire-off-peak-water-heater.html

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-- Edited by RickB on Wednesday 19th of January 2011 11:21:19 AM