I have a radiant floor heating application. It will contain an
Electric Hot Water Heater. This heater will NOT have a continuous
water source connected to it. Instead, the system will be a "Closed"
system. The water or anti-freeze will fill the Hot Water Heater, as
well as the tubes that go through the flooring. The fluid will return
back through the hot water heater in a Closed system.

I was told that if I get a leak in the system, I am in danger of a fire
hazard, since no fluid will be passing through the hot water heater
which has a heating element that will likely catch fire and create a
larger hazard.

I am looking for a way to sense when fluid stops passing back into the
hot water heater, and when this condition is true, I want to be able to
shut off the electricity supply to the Hot Water heater, to eliminate
my fire hazard.

Any ideas about what I should be seaching for?

wrote:

I was told that if I get a leak in the system, I am in danger of a fire
hazard, since no fluid will be passing through the hot water heater
which has a heating element that will likely catch fire and create a
larger hazard.

Methinks whomever told you that was trying to either create a lot of FUD or sell
you something you don't need.

Electric hot water heaters fail all the time and do not cause fires. If the
element is exposed, it overheats & melts inside the usually glass lined, metal
clad tank, and in the process, breaks the circuit.

Closed hot water heating systems have been around for hundreds of years. You
don't need to be inventing a new protection scheme for a properly designed and
installed system...

"Closed hot water heating systems have been around for hundreds of
years. You
don't need to be inventing a new protection scheme for a properly
designed and
installed system... "

That's for sure. Instead of trying to rig up a hack solution, why not
get the appropriate heat source for a radiant heating system?

And BTW, the shut off solution you think you need won't work. If there
is a leak and water loss, the water level in the tank will start
dropping. Water will continue to cycle around though, so you will
have water flow in the return line. When the water level gets below
the level of the upper heating element, it will then burn out, before
your cut off turns off the power.

On 25 Oct 2005 09:53:34 -0700, someone wrote:

That's for sure. Instead of trying to rig up a hack solution, why not
get the appropriate heat source for a radiant heating system?

Actually, using a HW tank *is* a recognized way of driving a radiant
system! BUT - neither a conventional hot water heat using a standard
boiler (NOT a "furnace" which refers to something that heats air), nor
a hot water tank used for this purpose, is actually "closed".

Most any modern boiler "hydronic" installation will have an automatic
fill valve connected to the water supply. It has a vacuum breaker
and/or check on it so that boiler water (which often has anti-freeze
in it) can't flow back into the water supply.

Set up this HW tank a similar way: vacuum breaker. Done.


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