Electric elements do "rot out" and expose the nichrome wire to the water. The
grounding/bonding will cause the breaker to trip if you have a lot of minerals
in the water. I would suggest removing them and giving them a quick look. If
they show signs of cracks or corrosion, replace them. They are cheap.
This can be exacerbated by buildup of those minerals at the bottom of the tank.
If the bottom element can't "breathe" it will quickly burn out and there is
plenty there to short it to the tank.
I have a piece of 1/2" CPVC rigged up to fit on my wet/dry vac to suck this
stuff out.

OT ... has anyone used engine heat, via a double isolation heat exchanger to
heat water? That sounds like a "free" way to do it if you are running.

On 14 Jun 2004 16:34:50 GMT, (Greg) wrote:

OT ... has anyone used engine heat, via a double isolation heat exchanger to
heat water? That sounds like a "free" way to do it if you are running.

=================================================

Not sure what you mean by a double isolation heat exchanger but most
marine hot water heaters have an internal coil for circulating engine
coolant and the heating water. It's very common if that is what you
meant.

Not sure what you mean by a double isolation heat exchanger

A double isolation exchanger is one with an intermediate fluid between the
potable water and the heating water. That way a single failure will not
contaminate your water. It is usually used any time the heating fluid is a
glycol mix.

On 14 Jun 2004 19:47:36 GMT, (Greg) wrote:

A double isolation exchanger is one with an intermediate fluid between the
potable water and the heating water. That way a single failure will not
contaminate your water. It is usually used any time the heating fluid is a
glycol mix.
===================================

Assuming you don't drink the hot water, a simple check valve in the
cold water supply line will suffice. I've never seen a boat with the
arrangement you describe, but anythings possible I suppose.

I think these systems are primarily in sailboats, to have hot water for
dishes and showers while at anchorage. Just like refrigerators that run
off of an engine mounted compressor.

Bob Dimond


In article , Wayne.B
wrote:

On 14 Jun 2004 19:47:36 GMT, (Greg) wrote:

A double isolation exchanger is one with an intermediate fluid between the
potable water and the heating water. That way a single failure will not
contaminate your water. It is usually used any time the heating fluid is a
glycol mix.
===================================

Assuming you don't drink the hot water, a simple check valve in the
cold water supply line will suffice. I've never seen a boat with the
arrangement you describe, but anythings possible I suppose.

I think these systems are primarily in sailboats, to have hot water for
dishes and showers while at anchorage. Just like refrigerators that run
off of an engine mounted compressor.

Bob Dimond

Most marine water heaters can work with either electricity or the circulation
of engine coolant through a coil. Has nothing to do with sail vs power. Heating
the water
with engine coolant means you can have hot water underway without running a
generator.

Okay. Is it really necessary to distinguish this point? IMHO the point
was adequately made that one need not be tied to shore power. Sheesh.

Bob Dimond


In article ,
(Gould 0738) wrote:

I think these systems are primarily in sailboats, to have hot water for
dishes and showers while at anchorage. Just like refrigerators that run
off of an engine mounted compressor.

Bob Dimond

Most marine water heaters can work with either electricity or the circulation
of engine coolant through a coil. Has nothing to do with sail vs power.
Heating
the water
with engine coolant means you can have hot water underway without running a
generator.