New water heater vs. Instantaneous heater?

[tedmalone]

I have an Atwood EHM11 water heater. It's supposed to be an 11 gallon tank, but the label says 8.5 gallons. Anyway, it's rusting on the bottom and starting to leak.

Before I rip it out and replace it with a new one, I wanted to find out if anyone has had any luck with the Eemax EX2412M tankless water heater? It's about the same price as replacing the water heater and I like the idea of instant, bottomless heat.

I'm concerned about its electrical requirements. In order to stay within the specs of the current water heaters electrical line (20 amp), I would need to get the smallest Eemax heater. At 1 gpm, that's only a 17-degree temperature rise. Not the hottest shower. I'd rather go with the larger (29 amp) model, but don't have any experience with upgrading a breaker. And, I've got lots of other circuits on that power line (port/startboard systems, fwd A/C, stove, etc.).

Any experiences and/or recommendations would be greatly appreciated.

 

[fwebster]

Tankless water heaters are generally not practical for boats due to the power demand. You want a 29A draw heater. There is a lot more involved in this than the breaker. The wire size will probably need to be increased and your generator does not have the capacity to power the water heater in addition to the other 120VAC demands like refrigerator, air conditioners, microwave, etc.

With a 29A draw, you will use 3.5KW which is about 1/2 your total capacity, and that does not take into consideration any starting loads.

 

[AKBASSKING]

I agree with Frank. Here is my experience with them:

http://clubsearay.com/forum/showthread.php?t=21358

 

[tedmalone]

Thanks for your response Frank. That's what I was afraid of. It seems like the safest route is to replace the EHM11. Maybe I'll go with the stainless steel EHM11SST this time.
:smt001

-Ted

 

[tedmalone]

Thanks for your reply too Tom. I read through your fresh water rebuild thread. That was quite the undertaking! Impressive.

-Ted

 

[AKBASSKING]

Thanks for your reply too Tom. I read through your fresh water rebuild thread. That was quite the undertaking! Impressive.

-Ted

Here is some further discussion on the subject, but I went with a SS, 6 gal HW heater.

http://clubsearay.com/forum/showthread.php?t=22625

 

[tedmalone]

I decided to play it safe. I ordered the exact same Atwood as a drop-in replacement. It is very accessible at the front of the bilge and shouldn't be too big a job. I just need to break the screws loose.