Tankless Water Heater-gctid352506

[Guest]

Is a tankless water heater a good idea on my 2655? Here is what im thinking about getting.

http://www.wamhomecenter.com/productcart/pc/eemax-ex3012m-marine-rv-tankless-water-heater-1165p79576.htm?atc=1&idproduct=79576

[2850Bounty]

The idea of no WH taking up space sounds good at first glance. However, what is your plan for powering 120 V, 25 A, 3 KW while on the hook?

IMO:

25 Amps/ 3 KW is quite a full load even while on shore power.

25 Amps/ 3 KW is too much to ask of an Inverter and HLBB that would suit your boat.

25 Amps/ 3 KW is too much to ask of a small portable generator.

A good quality 2-way Marine HW should provide engine coolant heated water in about an hour (or less) while under way.

It should also hold warm/hot water over night.

These can be found with .75, 1.2 or 1.5 KW electric elements that a small portable generator will handle.

In either event, you'll not want to power resistance heat via an inverter.







.

[Guest]

This seems like a cool idea, I just bought a 4K kohler to go in my boat. I like how small the thing is but, your right it does draw a lot of amps.

[2850Bounty]

Eric, I too have the Kohler 4 kw marine gen set, and it would be fully capable of operating that On-Demand WH.

Even with the capacity that I have, I'd not choose the On-Demand WH.

Here's my reasoning as to why!

With our 12 gallon 2-way WH we have:

increased our O/B water capacity by 12 gallons.

12 gallons of hot water when we reach our destination if it's 35-40 or more minutes out.

silent (minus the pump noise) hot water during the day. (warm towards the end of the day if we've used quite a bit)

silent (minus the pump noise) at least "warm to very warm" water in the morning.

Cost to have heated this.... ZERO.

If we end up needing to heat more water, we fire up the gen, or we take advantage of an outing.

Just offering some food for thought.

.

[Iproff]

erichz71 wrote:
Is a tankless water heater a good idea on my 2655? Here is what im thinking about getting.

http://www.wamhomecenter.com/product...dproduct=79576

I like the idea and will be putting that in my boat when my water heater goes. I have a 6 gallon water heater now but with my boat being raw water cooled the engine never gets hot enough to warm the water in the water heater. Even if I could run the boat while on the hook for 40 minutes to get me warm water it is far cheaper to start the generator and heat the water by turning the water heater on. If you have a closed cooling you might consider running the engine each day while on the hook but it has a large cost.

My boat uses .7 gallon an hour at idle bump it up to 2000 rpm from 600 and we are at 1.0 gallons an hour. My generator 1 gallon 6 hours, the cost of fuel in the area I boat $6.08 a gallon do the math of a week and you won't be starting the engine. Not last summer but the summer before I spent 7 weeks on the boat and less than a week at a marine most places 5 days anchorded out some even longer. If I ran my boat for 30 hours to warm the water in my water heater that would cost $180.00 in fuel it's a no brainer for me.

Ken

[Guest]

holy crap....25 amps on a water heater???....that's almost your entire pwr allotment at the pole...

no..I'd stick with a standard water heater if it were me....

:arr arr

[itsabowtime2]

:surr

seapuppy wrote:
holy crap....25 amps on a water heater???....that's almost your entire pwr allotment at the pole...

no..I'd stick with a standard water heater if it were me....

:arr arr

If I were to do something like this I would install a second 30amp service just for the water heater.

[2850Bounty]

Just for clarity re; a conventional Marine WH;

No one suggested running your engine specifically for the purpose of heating water.

The suggestion was to take advantage of when you are running the engine, by using the closed loop that allows engine coolant to circulate through the WH's heat exchanger.

Use shore power when you can, and use the generator when you can.

If/when you take a short outing, the engine will additionally heat water.

Again Eric, with the On-Demand, there is no storage of heated water as there is with the conventional unit.

With the On-Demand, it must be powered or you'll have no hot water.

On shore power... no problem!

.

[Guest]

Coleman makes a great portable tankless water heater that would be perfect for a 26 footer. I have one and am planning on using it for my shower. It works great and does not draw any serious amperage. Here is a link to the unit on Amazon.

[Guest]

first off all sorry to hi jack ur thread....

this topic is very interesting I have a hot water tank in my boat but no clue if works....lol...

What would be a reasonable size for a boat WH?

How many people would be able to take a shower with that?

How hot the water in this heaters they can reach?

I have a raw water cooling should I connect to the WH to help bring the water temperature UP....even that I dont have a closed cooling system?

tks.....

[706jim]

Alexirocz28 wrote:
first off all sorry to hi jack ur thread....

this topic is very interesting I have a hot water tank in my boat but no clue if works....lol...

What would be a reasonable size for a boat WH?

How many people would be able to take a shower with that?

How hot the water in this heaters they can reach?

I have a raw water cooling should I connect to the WH to help bring the water temperature UP....even that I dont have a closed cooling system?

tks.....

1. Boat water heaters are usually 6 US gallons.

2. Two people if you use a flow reducing shower head and one of the people is not a girl with long hair.

3. As hot as you want; hot enough to scald you if you wish.

4. Yes, hook up your engine to the heater and it will heat the water within 30 minutes of operation (more or less).

[Guest]

1/2 hour??? REALLY!? I am very impressed!!!

It's it better to have 2 small 6 gallons or 1 big 12 gallons?

Tks you so much for the info....

[706jim]

Alexirocz28 wrote:
1/2 hour??? REALLY!? I am very impressed!!!

It's it better to have 2 small 6 gallons or 1 big 12 gallons?

Tks you so much for the info....

Half hour.

Really.

You COULD install two 6 gallon tanks "in series" and you would have more hot water in nearly the same time interval (the hot "engine" water is not cooled much going through the heat exchanger loop in these small tanks), but keep in mind that fresh water storage is limited in most boats and that water is quite heavy to haul around. You would probably have difficulty finding room in our small boats to install two separate tanks.

Water in these electrically heated tanks can also be warmed up using a small Honda generator if you were at anchor.

[Jeffw]

If you're in relatively clean fresh water, or you have another water source, you could use one of these for showers:

http://www.campingworld.com/shopping/item/eccotemp-portable-tankless-water-heater/37786

We use ours hooked up to the washdown pump, which draws lakewater, and gives us as much hot water as we want.

[Guest]

On a crowded dock in the Summer that unit, at 25A continuous will be constantly popping the breaker. Great if you want your shower to turn cold half way through...

Dave