Selecting a New Water Heater

[Dalliance]

I need to replace the water heater in my 1982 Hunter 30. It will only be used on shore power (120v, 30 amp service), no engine heat exchange. The old one is a six gallon size, round upright configuration, and nothing larger is going fit. If you've replaced a water heater recently, any advice would be appreciated - do's, don'ts, recommended brands, brands to avoid, etc.
I'm curious about the tankless demand type water heaters too. For energy conservation and the possible small convenience of having one less tank to winterize, though I have some concern about the amperage some of them seem to draw. Has anyone installed one and if so, are you satisfied with it?

 

[Steve Dion]

Try checking out a Bradford White 4 Gal. Commercial electric unit. High recovery rate so it should be good for a dockside companion.

They should fit through the starboard locker too.

 

[Dalliance]

Thanks Steve. That's a company I had not heard of and will take a serious look at.

 

[Barnacle Bill]

There are a number of hot water heaters on the market. Why wouldn't you plumb it into your engine heating system (heat exchanger)? Then you'd have heat while at sea too (for a while). I assume that since you had a heater already there, to replace it is very easy to do, especially if you buy the same brand. Then everything will fit. You just hook the hoses up the same way they were hooked up on the old unit. Same with the electrical wires. No big deal. And....if the old one was plumbed into a heat exchanger, you again, just put the original hoses on to the new water heater the way the old one was. You mentioned other tankless water heaters. Well, they are either electric or propane. You would have to have a propane system in your boat to use one of the LPG types and it would require a more difficult installation. Many of the propane water heaters were on boats from Canada and not really accepted in the U.S. for insurance reasons. Electric on demand (tankless) water heaters are not as hot as the tank type that you had. The temperature has a great deal to do with the temp of the water in the tank and so temperature at the faucet is not reliable like a tank type. It would be so easy to just buy the same unit and hook it up the same way. The installation would be very quick, actually. If it is plumbed into a heat exchanger, you have to bleed the antifreeze part of the system. Most likely you will have air trapped in the system and that could cause over heating. Make sure it is bled properly and that will not be a problem. If your old water heater was round with a white body and blue top and bottom, it is readily available still. Why are you replacing it? Doesn't heat water anymore? Might just be the heating element is burned out. In which case you can simply replace that? If the steel tank or aluminum is corroded or cracked (not winterized properly?) then you need a new water heater. One never turns on the power to the heater if there is no water in the tank. That will burn out the heating element. Always make sure there is water in the tank before flipping the water heater switch.

 

[Steve Dion]

Bill:

The older Yanmars did NOT have a heat exchanger. Running the raw water thru the water heater will not produce enough heat to heat the water to a proper temperature.

His option would be to add a heat exchanger to the engine which is not cheap.