Stainless
Steel
The decision to
use stainless steel for the manufacture of the "Tank in Tank" was
made in the 60's. It was chosen for its well established reliability and advantages
over other materials, namely: Stainless steel is stable at elevated temperatures
above 180ºF, which is not the case for tanks manufactured from mild steel
protected by a glass lined coating. It is for this reason that some manufacturers
include a clause in their guarantee limiting the DHW storage temperatures
to 140°F or even 130°F. Stainless steel, as its name suggests, is
resistant to corrosion. The protective coatings in a vitreous enameled tank
can be damaged by a shock during transportation, unloading or maneuvering
it into position. This is not the case with stainless steel. Last, but not
least, a stainless steel tank does not need a sacrificial anode. This is a
major advantage versus conventional water heaters. Stainless steel is also
universally recognized for its hygienic properties and is frequently used
in the manufacture of items for the food industry and for surgical instruments.
There is little chance of its use being questioned on the basis of it being
a health hazard. Conversely, protective coatings, i.e. enameling cannot be
examined everyday and their failure could lead to unhealthy consequences.
Tank-in-Tank
There are two major types of water heaters, those with coils and the twin
walled tank. The water heater which we manufacture, the "Tank-in-Tank",
doesn't fall within either of these categories. The difference between our
water heaters and those with coils is clear since in the former the primary
fluid heats the domestic hot water form the outside while the other heats
it from the inside out. On the other hand the twin walled water heaters have
an area near the bottom which is not heated and the heat transfer surface
is smaller than in the "Tank-in-Tank". It is also necessary to note
that only the "Tank-in-Tank" protects the user against flooding.
In cases of the hot water tank rupturing the water will simply join the heating
circuit. The only consequence of this will be a higher than normal pressure
in the primary circuit. Despite all this the most important characteristics
of the "Tank-in-Tank" are its capability for auto-descaling and
its long life expectancy combined with the
reduced requirement for regular maintenance.