Hot Water Heater Recommendations Please

[Shrew]

Originally Posted by steve77

He's referring to the seemingly redundant term "Hot Water Heater". Some people think it should just be a "Water Heater".

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'.

[Dockhead]

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'.

Ha, ha. Pedants of the world, unite!

Of course you're right, and it bothers me also somewhat, but it's an uphill battle. "Hot water heater" is natural speech - heater which produces hot water.

Double negatives are also illogical, but like "hot water heater" - natural speech. Double negatives were driven out of English by pedants like you and me fairly recently, contrary to common speech. Interestingly, in the Russian language, which is the most grammatically complex living language (or at least tied with Polish and Ukrainian), double negatives are not only tolerated, they are actually MANDATORY And if there's a place in the sentence for a THIRD negation - you must do a TRIPLE negative.

[Bill O]

Really, we all know that the OP is asking for a water heater and aren't just splitting hairs here.

I can think of at least one situation where you are continually trying to heat water after it's already hot. With an engine coolant loop and one continues to run the engine, you are attempting to add additional heat to the water after it's already hot.

[Bill Seal]

Actually, double negatives are somewhat required in DMV exams.

[senormechanico]

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'.

And then there's the "...at 7 AM in the morning..." crowd, especially news reporters on TV.
It's either 7 in the morning or 7 AM, not both.

The latest one is "Joe Blow, he did something."
It should be, "Joe Blow did something."

[rwidman]

Originally Posted by Nord Sal

Why would you need to heat hot water?

That one had me scratching my head as well!

[michaeld]

Thanks to everyone that provided relevant water heater advice and/or experience.

[kmacdonald]

4 gallon isotemp here. No issues in 3 years. Doesn't require the space of a Raritan.

[bstreep]

We have a Kuuma water heater. Just replaced it. Again. Found this out: There is an optional anode I just found out about on this replacement. It has to be checked every 6 months, as if you wait too long, they are hard to remove. Anyway, food for thought.

BTW, I'm a real estate appraiser. It's a water heater. And there is only one "a" in Realtor. They are NOT Realators. My favorite redundant comment was from a DJ years ago: "This is from his first, initial, debut album".

[Dockhead]

Originally Posted by alaskanviking

I have an isotherm 40L. It came with the boat, not sure when it was installed, guessing 15-20 years old

It has always worked well, water stays hot ~24 hours. The 750 watt electrode has generally heated water fast enough. Not sure about the quality of the newer ones.

I will be installing a new one later this year, redoing my water system. I need a dual heat exchanger model so I can heat both with the engine and with a diesel water heater. There is a isotherm 40l dual exchanger model ~$1200, US made stainless tank.

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

I have not been able to find a comparison between the UK heaters and us heaters. So it's all guestimate, however I seen canal boats review them well and they appear to hold heat for 24 hours. The copper as an antibacterial, well that is generally true and it makes sense that bacteria and scum doesn't grow on the inside of the tank. not sure if the application here works well for that. I have a 240v system, 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. The copper tank can have issues with pressure. The pressure valve is set low on the UK models 3-4 bar. If the water heats up and over pressurises, then cools and contracts repeatedly the copper work hardens and can crack. I'm not sure how or how often this will affect you in reality but something to look into and consider because you more than likely have to upgrade to the 5 bar valve for us systems. I believe the tank fittings are also metric/euro types (not npt) so you will have to get adapters. Size wise they are approximately the same size as the isotherm. So these water heaters are a little bit cheaper but you have to get extra stuff. I have noticed that many of these features (copper tank, and titanium heating elements) are used in high end US house water heaters. So I'm thinking maybe the marine market has not kept up with current trends. Again I haven't seen any comparison so I don't if it's worth while compared to an isotherm

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

Isotherm on my boat as well. Can confirm that the UK made calorifiers are top shelf. Unfortunately with a price to match, but in my view worth it. I got mine from ASAP Supplies; recommended. They ship worldwide.

[NSboatman]

Solid vote for the Quick brand of water heaters. Replaced an old Raritan with one about 5 years ago and it’s miles better (than the old Raritan). New Raritan might be just as good.

[sailcrazy]

We replaced our 17 yr old Force 10 water heater....with another Force 10 water heater. and now, some 16 years later, it is still working flawlessly, without issue. Ours is mounted in the eng room, over the engine, and is heated by either eng fresh water cooling system or AC electricity. It is an 11gal s/s tank, with s/s cover, and provides more than ample hot water for the 2 of us....on anchor we use the genset about every 2nd to 3rd day, and when we motor, the water is always hot. totally satisfied!

[SV__Grace]

We are happy with our Hurricane because-

- diesel or electric hot water source
- unlimited on demand hot water (while diesel burner is running)
- hydronic heating of the boat (one device does both hot water and heats boat)
- can connect to engine heat exchanger (4.5 gallon internal capacity depending on model)
- can switch hydronic heat system on or off (burner only needs 5 minutes or so from cold start to fully heat up for hot water only, longer to heat up the hydronic system, very economical for hot water only)
- excellent tech support and customer service from manufacturer ITR Research (Canada and US locations)

It's not cheap and probably overkill if you don't need to heat the boat in warmer climates, but it's high quality, easy to service, and helped us get through the coldest winter in many years here in the PNW thanks to this baby.

[Boatyarddog]

Originally Posted by rbk

I’ve been looking as well and isotemp looks good but I’ve been seeing too many horror stories recently and they all seem to be similar stories. They really look like a quality product, good insulation, decent price and mixing valve (most don’t) but rusty failed welds keep popping up in reviews. If isotemp would acknowledge this and correct it I wouldn’t hesitate, until then I’m sceptical. While warranty does seem to be honoured it’s still the inconvenience of replacing seals, or swapping the tank, purging the cooling system etc every year or two.

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

[svfinlandia]

Originally Posted by Nord Sal

Why would you need to heat hot water?

You beat me to it!
Like me, I’m sure you just couldn’t resist.
It’s kind of always been one of my pet peeves - calling a water heater a “Hot” water heater. Like you, I always have to ask “if the water is already hot why do you want to heat it”

Al, S/V Finlandia