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.

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

?????????

Are we having the same discussion?

I thought you posted that hot water heaters
that circulated engine coolant through a coil to warm up the hot water were
found primarily on sail boats.

I correct that erroneous idea and you wind up "sheeshing"?

What's with that?

You said:

I think these systems are primarily in sailboats, to have hot water for
dishes and showers while at anchorage.

How did I misread that?

Sorry, Gould. Bad day. Still, my point is made. The idea is that heat
exchangers are to allow use of the system when the boat is not tied to
shore power.

Perhaps this prevelance is influenced by geography, but I've seen this
type of system on more sailboats than powerboats of comparable size.
These observations support my statement that this setup is more prevelant
in sailboats. Sailboats are more likely to be underway for longer
periods of time and are more likely to be anchoring without ammenities.
Add to that my statement was in response to a powerboater who has never
heard of such a system and it supports my viewpoint...

You point out the obvious that these can be used on powerboats as well.
Your personal observations may disagree with my statement that the system
is more prevelant among sailboats, but your just picking nits.

Bob Dimond

"Bob D." wrote in message
...
Sorry, Gould. Bad day. Still, my point is made. The idea is that heat
exchangers are to allow use of the system when the boat is not tied to
shore power.

Perhaps this prevelance is influenced by geography, but I've seen this
type of system on more sailboats than powerboats of comparable size.
These observations support my statement that this setup is more prevelant
in sailboats. Sailboats are more likely to be underway for longer
periods of time and are more likely to be anchoring without ammenities.
Add to that my statement was in response to a powerboater who has never
heard of such a system and it supports my viewpoint...

You point out the obvious that these can be used on powerboats as well.
Your personal observations may disagree with my statement that the system
is more prevelant among sailboats, but your just picking nits.

Bob Dimond

A lot of the tournament ski boats have heat exchanger showers. Would skew
the numbers away from sailboats.

Can you even buy an electric marine hot water heater that isn't pre-plumbed
with a heating coil?

In cases where such a heater is installed in a boat that doesn't have a closed
cooling system, I usually see the fittings for the coil capped off.

I have seen some household type water heaters stuffed into the bilges of
Cruise-a-homes and outboard powered boats with shorepower conections. The vast
majority of time they rot out very prematurely.