Demand Water Heater

[Rex Delay]

Is there a Demand Water Heater (propane) which is acceptable for marine use? Found a diesel one but cost prohibitive. I sure miss my old Paloma and hot morning showers.

[rsn48]

I installed an on demand water heater in my Winnebago (propane) and I'm not thrilled with it. I suspect water pressure is the issue and I need to up the pressure to improve performance. You will read about cold spots with some and mine has that in spades. And the heat seems to come and go, either the water isn't hot enough, or I'm scalding my hand, and which point, it goes back to tepid.

When you find one that you feel is suitable, review, review, review it, before purchase.

I do have a home on demand water heater - natural gas - which I quite like

I'm trying to remember which brand I have but recall is evading me.

[hellosailor]

Well, Rex, I used to crew with the guy who was nearly killed by an early Hot Walter installation that later got a late of court and press time. He only survived because he'd been down in the luxurious hot shower for a suspiciously long time, and the skipper was an MD.

The real question is not just the certification, but the heater MUST be installed in such a way that no combustion products can get below. That can mean installing the heater on the outside of the cabin, or a sealed aft locker (like a propane locker) or...the electric ones make monoxide problems impossible. Not entirely a bad idea.

[Oldwheels]

I too have wanted to do this. Combustion gasses have to be vented as I thought about a powered vented system.
I have lived with these in my house and the down side is flow has to be good enough to make it turn on. This can be difficult when only a little hot water is needed to temper a shower.
Presently I have an electric hot water heater which I run from my generator. This takes about ten minutes to warm 5 gallons. Works well enough.

[Lepke]

Many commercial fishermen have propane water heaters for showers. Usually mounted outside or in a locker vented to the outside (for safety). It's not like a house tank where you mix hot and cold. You set the temp for the desired shower temp and only use hot.

If you plumb a hot water heater w/o check valves, as the tank heats, it pushes hot water into the cold lines. You set your temperature, start your shower and then the cold hits.

[Pizzazz]

I looked into this as well, at the time ad a hydronic heater. You can get well reviewed examples on Amazon for $120. May be worth experimenting with it. I think the propane issue is over blown (not a big deal for a 5 min shower, the hatches are usually open). The bigger danger is that one day you will forget it when tired, coming down from a watch, etc. and then it is dangerous. Then you will likely run out of propane.

Best solution is a regular marine heater (engine/electric). Well worth the money.

[billknny]

Originally Posted by Pizzazz

I looked into this as well, at the time ad a hydronic heater. You can get well reviewed examples on Amazon for $120. May be worth experimenting with it. I think the propane issue is over blown (not a big deal for a 5 min shower, the hatches are usually open). The bigger danger is that one day you will forget it when tired, coming down from a watch, etc. and then it is dangerous. Then you will likely run out of propane.

Best solution is a regular marine heater (engine/electric). Well worth the money.

I get it... not a big deal. Until you die.