Over the years, we have been aware of many different approaches that
people (and competing products) have used to accomplish this goal.
Hot Water Heating and JUCA
First of all, we want to emphasize that all JUCA products are designed
to be appliances that create WARM AIR to be distributed around the
house. That is certainly their primary function.
However, since they work so very well at this task, customers sometimes
realize that the JUCA is capable of creating and supplying even more
heat than they are using. Sometimes they use this extra capability
to send heat to a basement, a workshop or a garage that otherwise
wouldn't be heated. But then sometimes people ask about getting some
benefit from their JUCA in heating water.
There are three primary applications for which they are thinking.
- Hydronic Hot Water House Heating. This use, of supplying
enough hot water to entirely heat a home, is NOT realistic with a JUCA.
There MAY be possibilities of a PARTIAL Hydronic system, if the JUCA
is allowed to heat most of the house with its warm air, and the Hydronic
heating is only needed in one or two distant rooms.
- Heating water to supplement a Solar Heating System.
This is often a realistic usage of heat that a JUCA could put into
a water medium.
- Domestic Hot Water. This is the most realistic usage of
heat that a JUCA can put into water.
JUCA has never and will never get involved in supplying any of the
stuff for these sorts of experiments. We are just telling you our
experience and passing along some of the experience of previous
owners who have experimented in this area.
- There used to be a company from California that made a thin, heavy
steel box, with pipe fittings, that was meant to be put into the
firebox of a woodstove. We always thought this was a bad idea. It
certainly could produce hot water, and was probably one of the most
effective ways of doing it, since the water filled box was just inches
from the fire's flames. But, such contraptions OFTEN got too hot,
allowing the water inside to get above 212°F. Since the water wanted
to boil, it would build up HUGE pressures, and would depend on a
Temperature-Pressure Relief Valve to keep it from exploding. If that valve
failed, then the device or the attached piping could burst, spraying
scalding water all over. Please DON'T consider such devices!
- For many years, we experimented with inserting coils of copper
tubing INSIDE the heat exchange tubes of a JUCA (up above the fire).
The tubing was protected from the corrosive atmosphere of the firebox.
It was located in a very hot area above the fire. And, best of all,
the warm AIR passing through that heat exchanger tube (and through
the middle of the coil) would TEMPER the water. IF the water ever
got to 200°F, for example, the 140°F AIR would actually cool it down
and would keep it from boiling. And, we found, if we put a partial
restriction in that heat exchange tube, we could cause the AIR
passing through that tube to be regularly at 120°F, 140°F or 160°F,
thereby sort of pre-setting the average water temperature it would
- Finally, a customer recently suggested this approach. Before pouring
the castable firebrick in the floor of the JUCA, he was going to
lay a flat copper tubing coil (the way it's usually sold these
days in 50 foot lengths) on the bottom. By burying it under the
castable firebrick, making sure that it is beneath more than
an inch thick of that material, he expected to make sure the water
never boiled. And yet, the castable is quite near the fire and is
able to absorb quite a bit or radiant heat from it. The castable
firebrick should act to temper the water temperature, and generally
keep it from boiling.
IF YOU EXPERIMENT WITH ANY OF THIS, YOU MUST INCLUDE A
CIRCULATING PUMP AND PRESSURE-RELIEF VALVE IN THE WATER LOOP
because you definitely DON'T want the water to boil and burst the
pipe or otherwise explode!
All of these ideas depend on the small hydronic circulating pump
to keep removing the heated water from the box or tubing in the
firebox. In general, the idea is to just raise the temperature
of the water a couple degrees each time it passes through the
coil, gradually raising the temperature of the hot water tank's
contents. After many passes through the coil, all of the water
in the circuit (tank, pipes and coils) will be near the desired
Obviously, this brings up an important consideration. IF you have
a power outage (and you will), the pump will stop circulating,
and it becomes rather likely that the small amount of water in the
coil will build up very high pressures. THIS is why the Temperature-
Pressure Relief Valve must be in the circuit, and it should be
relatively near the heating coil. Superheated steam would be
ejected from the valve at that time. This subject is VERY
IMPORTANT to consider because it WILL HAPPEN. And you DEFINITELY
don't want anyone to get hurt or anything to get damaged as a result.
Don't try any of this unless a professional
plumber gives guidance and / or does the installation.
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