Market Forge Industries ST-3E ユーザーズマニュアル
13
PRINCIPLES OF OPERATION
GENERAL:
The Steam-Tech represents the latest in counter top
steam technology, designed to apply the benefits of steam
cooking to today’s health-conscious menus. A “close-
coupled” steam generator system gives quick start-ups
and efficient steam transfer to the cooking compartment,
without the use of fans or expensive blower motors. In
tests for energy efficiency and cooking times performed
in accordance with ASTM standards, the Steam-Tech
yielded impressive results over other similar counter
top steamers. This section includes explanations of the
steam generation, control, and drainage.
FILL/COLD WATER INLET:
When the power switch is pressed into the “on” position,
a normally closed solenoid operated fill valve energizes
and opens. The valve supplies cold water to the steam
generator. At the same time, a normally open solenoid
operated drain valve energizes and closes allowing the
steam generator to fill with water (until the factory prede-
termined level is reached).
The water level in the steam generator is sensed by high
and low water sensor probes which are mounted on the
front of the generator. The probes are connected to the
electronic water level control board which, controls the
opening and closing of the generator fill valve. When
the water level has reached the high water level sensor
probe, the electronic board cuts power to the generator
fill valve. As steam is created and used up, the water
level in the steam generator will drop. When the water
level falls below the level of the high water level sensor
rod, the electronic board will close the circuit to the gen-
erator fill valve, allowing fresh water to enter the genera-
tor until the water has risen back up to the level of the
high water level sensor.
PREHEATING & STANDBY:
When the water level in the generator has risen up to
the low water level sensor probe, the electronic water
level control board closes a circuit which activates a re-
lay. This relay supplies power to the heater. The heater
will stay on at full power until the water temperature is
sensed by a thermostatic switch mounted inside the
steam generator, below the water level. The steam gen-
erator will standby or idle at 195°F ready to make steam
when it is called for.
STEAM GENERATION:
The Steam-Tech will not create steam until it is called for.
Steam is called for by setting the timer/selector switch
to either constant steam or timed steam. The cooking
compartment door contains a magnet which activates a
magnetic reed switch.. The red switch is located behind
the front face of the unit, next to the cooking cavity open-
ing. When the door is opened, the magnet and switch are
separated. This opens the circuit to the heater, which will
halt the creation of steam, but allow the heater to main-
tain 195°F water temperature in the steam generator.
When the unit is on, the heater will maintain 195°F wa-
ter temperature in the steam generator, to insure quick
generation of steam when it is called for. When steam is
called for, a circuit is closed which activates a relay. This
relay closes the 208v, 240v, or 480v circuit which sup-
plies power to the heater. The generator now begins to
create steam. Steam passes from the steam generator
directly through the side of the cooking compartment.
The fresh steam entering the cooking compartment forc-
es the colder air to the bottom of the compartment and
down the cooking compartment drain line. The cooking
compartment drain line then has cooling water is sprayed
into the drain flow. The cooling water is controlled by a
thermostat located downstream of the cooling water
nozzle. This configuration reduces the drain flow tem-
perature to below 140°F. When the unit is steaming, the
cooling water flow is on continuously. The cooling wa-
ter comes “on” demand during other steamer functions
such as generator blow-down (drain).
HOLD FEATURE (OPTION):
The Steam-Tech has a unique hold option which allows
it operate as a holding cabinet at the end of a steaming
cycle. The optional hold feature is activated by selecting
the hold mode using the mode switch at the end of the
steam cycle. While in the hold mode the generator will
idle at 195°F, ready to create steam again.
When the thermostatic switch senses that the temper-
ature of the cooking compartment has dropped below
170°F, it activates the steam generator. This will raise
the temperature inside the cooking compartment. When
the thermostatic switch senses that the temperature of
the cooking compartment has risen to 175°F, it cuts pow-
er to the generator. This system insures that the internal
temperature of the cooking compartment will stay within
a safe holding temperature range of above 150°F. The
temperature of the cooking compartment can be moni-
tored by observing the temperature gauge. The tem-
perature gauge is located at the bottom of the the control
panel.
DRAINAGE:
COOKING COMPARTMENT DRAINAGE:
The bottom of the cooking compartment is angled slight-
ly towards the rear of the unit. This assures that any con-
densate build-up or spills will be directed towards the
drain hole which is located at the bottom center at the
rear of the cooking compartment. Any liquid exiting the
cooking compartment runs down the cooking compart-
ment drain tube and into the drain line.
STEAM GENERATOR DRAINAGE:
Steam generator drainage is controlled by a normally
open solenoid operated drain valve. When the power
switch is pressed into the “on” position, power is sup-
plied to the drain valve, which causes it to close allowing
the generator to fill. When the power switch is pressed
into the “off” position, power to the generator drain valve
is cut, causing it to open. The steam generator will now
automatically drain.