Hot Water Heater Recommendations Please

[rbk]

Originally Posted by Boatyarddog

Why do you purge the cooling system every year or two.
Air pockets? Or ?
Never have a problem with mine.
Boatyarddog

If you’re having to remove the water heater due to warranty issues ie full replacement every other year.

[Bent Bugle]

Have a look at ATI models, 316 s/s inner tank & heat exchanger, 304 ss outer tank, 120 - 240 volt connection,12l -60l capacities,I fitted a 22l tank ( I'm a plumber & gasfitter), to my cat 2 yrs ago & so far no issues. The prices are reasonable & I can't see any difference between these & the top range models...if you don't fit a tempering valve I'd at least have a decent size accumulator tank fitted to the pump outlet line to reduce pump cycling...high temp hot water & cycling pump water don't really go together when your in the shower...

[LastCall41]

Our Paloma tankless propane automatic has supplied hot water to both heads and the galley for as long as i can remember. Check it out. Ours hangs on the wall In the aft head. Totally out of the way.

[Cheechako]

Small marine water heaters seem to last 7 +years regardless. A common brand name that is cheap is probably the way to go. Just consider it a replaceable item. Not convinced SS is better, and may be worse.

[Cyrus Safdari]

Originally Posted by Shrew

There is nothing 'seemingly' about it. You heat water. You don't heat hot water. And it's not SOME people. It's EVERY SINGLE water heater manufacturer out there. None of them refer to their products as 'hot water heaters'.

Well to be more pedantic, it isn't a water heater at all since the engine does the heating (if it had its own heating element that would make it a "broiler" - which is actually something to consider as alternative), all the this does is store the hot water heated elswhere so in some places they're called "calorifiers"

[Marathon1150]

Originally Posted by LastCall41

Our Paloma tankless propane automatic has supplied hot water to both heads and the galley for as long as i can remember. Check it out. Ours hangs on the wall In the aft head. Totally out of the way.

We have a Rinnai tankless water heater to provide hot water to our house. It is brilliant. And on a boat, these units will provide hot water without being plugged into shore power or running the engine. We strongly prefer to sail and on long passages, the engine isn't used for many days at a time. We use camp shower bags but if there isn't a lot of sun, cockpit showers can be a bit cool.

What I am not sure about is venting for the exhaust. I have only ever seen one installation on a boat and I can't remember if or how it was vented to the exterior. Presumably the approach used with propane/diesel bulkhead mounted heaters would work?

[Bent Bugle]

The Rinnai's are good heaters but for external install only..exhaust vent issues.. I've seen them on commercial boats & always on an outer b/head or similar..they do chew the gas & you need to route H & C water & gas as well...if your'e on a budget replace like with like, the plumbing's already there,hot water virtually free from the motors cooling system...if no budget constraints, well....skies the limit..

[David B]

Originally Posted by michaeld

I have spent quite some time Googling for a hot water heater. I'm confused, so I'm hoping collective knowledge/expertise will help point me in the right direction. Assume only two aboard, water conservative showers. Engine heat exchanger and 115VAC required. No more than 5-6 gallon size.

Experience & advice solicited... Make/Model Good/Bad/Ugly

Thanks!

Quik make a very nice product - very happy with ours 10 years on.
https://www.quickitaly.com/en/produc...tic-boiler-b3/

[senormechanico]

Originally Posted by bstreep

"This is from his first, initial, debut album".

A very excellent example. /sarc

[captmob]

On my 3 rd sailboat and have had Raritan heaters. Rarely had a problem l. Just changed the one in my 416 last year, it is 35 yrs old. Guess what I replaced it with… a 20 year old used one I had in the workshop.

[Martinini]

Lots of people here talking about the most expensive ones out there. Most "cheap" ones with a heat exchanger work just as well as any of the high dollar ones. Paid $250 US for mine 15 years ago. I refuse to pay for "Names" any longer.

[Wildcats]

We had a Whale Seaward aluminum 11 gallon tank on our Ranger Tug. It had a 1500 watt heating element. We noticed that the screens on the faucets were becoming clogged with aluminum oxide (the tank is aluminum). We decided to replace the tank. We purchased an 11 gallon Isotemp stainless tank with a 750 watt element. We wondered if the 750 watt element would be adequate for the two of us. It is not an issue though, and we have plenty of hot water for the two of us to shower. Initially, the water temp was too low for our liking even with the unit turned to maximum. I contacted Isotemp and they told me that the proportioning valve could be loosened and the temp adjusted to a higher temperature. That worked like a charm. Our potable water tank in the Pacific Northwest (San Juan Islands) gets cold so that may be the reason. The mixing valve added very cold water to the output. One comment about installing the Isotemp. It works well but beware that it comes with British pipe threads (BSP) while the U.S. and Canada use American pipe threads (NPT= National Pipe thread). The difference is the angulation of the thread, British being 55 degrees while the American/Canadian pipe is 60 degrees angulation. I thought it wouldn't be a consequential difference but boy was I wrong. I finally had to get a BSP to NPT connector. Without this it was a heck of a time getting the connections to stop leaking. The threads didn't match up well without the connector.

[merrydolphin]

IsoTemp for sure. They hold the hot longer than any other and they are highter quality. Will not rot/rust out. Worth it. A clear winner. I have had Rarititan and Atlantic are disposables comparatively and don’t hold the heat as long nearly as long.

[Seafarer7]

Originally Posted by alaskanviking

…
I have also been looking at some of the UK water heaters. Surejust, Surecal and Hotpot are 3 of the brand's. These have copper tanks, dual exchangers, and can choose different electrode elements including a dual 240vac 750w/ 12vdc element that would be easy to tie into your solar. The elements are Titanium which matches high end house hot water heaters in the US. the insulation is the waterproof poured foam type so it will be good even if it gets wet, similar to isotherm. Many US marine water heaters use regular fiberglass insulation and when it gets wet it degrades and won't hold heat.The copper in the tank is supposed to be antibacteria, and in theory will remove the dissimilar metals from your potable water supply if you use copper or plastic fittings. Heat exchangers are also copper so they will transfer heat from the engine more efficiently. The include a antiscald temp mixing valve which appears to only come on the higher end us units. I found these in 30-40l for approx $800 but you need to include shipping, so I've been estimating ~$1000

………….
, but they do have 120v electric heating elements, you will have to order it with it or order the extra element and install it yourself later. The dual ac/DC element only comes in 240v/12v however so if you only have 120v that may not work for you.
…………..

Practical sailor did a water heater teat and isotherm was up at the top.

Second vote for Surecal/Surejust (they are one and the same thing, Surecal is made by Surejust and sold by heatso). I got the dual-element, dual coil 30 liter unit with 120v AC and 12 V DC heating elements - they do exist @Alaskaviking: but it might just be using the 240v coil as my measured coil power is about 800watts on 120v US. Shipped from the UK, took a while to receive in the US. The DC element is about 150watts, ideal for soaking up the left-over energy from the solar panels when the batteries are in float or absorption. Dual coil allows heating from both the engine and the hydronic diesel loop.
Prior to this I had a brazed plate heat exchanger installed inline with a 6 gallon Atwood heater. The heat exchanger, heated off the hydronic cooling loop, allowed for unlimited instant hot water, independent of the Atwood tank.

[hjohnson]

We have a little isotherm hot water tank on our E27. While we don’t have a shower, it is lovely for doing dishes. We did have to rebuild it recently (heating element is oil filled I think, and made the water dark grey. But when opened it up, could tell that the inside was still in perfect condition, even after 10 years.

It’s only 5.5 gallons, but given that it sits at around 90C inside then used a tempering valve to produce safe temperatures, it acts more like a 10 gallon tank. It’s also very well insulated, and will keep water hot for a good 6 hours after we leave the dock (raw water cooled engine, so heat exchanger isn’t hooked up).