Tankless hot water heater

[DDW]

Simi, what are you going to do with only 6 gallons of hot water??? By the time it gets mixed down with incoming cold water you're likely to obtain about 3-4 gallons of hot. 2 people living full time, showering, washing dishes, etc.

6 gallons is the common size for most RVs, works fine for showers, dishwashing, etc even full time 2 people. Lived in one for 6 years while building our house, never a problem. If you mix 6 gallons with some cold you get more than 6, not less. On the trawler, I have a 20 liter heater that also works fine for two. If you have a 4 gal/min shower head and like 20 minute showers, you are going to have more trouble with the watermaker than the heater.

Paloma propane water heaters were common on Canadian cruising sailboats in the early 1980s. But there were several deaths attributed to CO poisoning from this type of heater, and they disappeared from marine use after that.

I had a sailboat with the Paloma. It worked fine, you did have to open the tap enough to get flow for it to kick on. It had a standing pilot, which was a bit of a concern. There was another brand which was responsible for the deaths, not Paloma, AFAIK.

All that said, a hydronic system like the ITR provides essentially unlimited hot water.

 

[Portage_Bay]

I installed a Hurricane Chinook hydronic heating system in January 2021. Part of its features includes what they call an on-demand domestic hot water system which I've used extensively this last year.

It's not 100% like an on-demand hot water system in that it has a reservoir which has about a 7 gallon capacity which when it is on is always hot. However, I've run that out (I like long showers) and the system can produce 1.5GPM of hot water continuously while heating. I've seen it do that many times and it's pretty impressive.

Again, I know it's not an instant or on-demand water system from the very beginning, but you can turn it on, and within 3-4 minutes have 1.5GPM of hot water pretty much until you run out of water.....

Sure marine sells the Everhot on demand water heater. https://www.suremarineservice.com/G...s-On-Demand-Copper-Water-Heater/W001-105.html
It will work with any hydronic system or engine heat exchanger as long as there is enough heat output to meet demand. It's not tankless but you won't run out of hot water until you run out of water or fuel. Had one on a boat with a crew of 8. No one ever got a cold shower.

 

[Rmlow]

Sure marine sells the Everhot on demand water heater. https://www.suremarineservice.com/G...s-On-Demand-Copper-Water-Heater/W001-105.html
It will work with any hydronic system or engine heat exchanger as long as there is enough heat output to meet demand. It's not tankless but you won't run out of hot water until you run out of water or fuel. Had one on a boat with a crew of 8. No one ever got a cold shower.

We have an Everhot on demand system coupled to a Webasto hydronic heat system. The system works well provided the webasto furnace or main engine is running. Whole system was from Sure Marine. Haven’t been able to run it out of hot water yet.

During warmer weather, the cabin heat loops can be valved off at the manifold to provide heat only to the Everhot exchanger.