17
VARIETY STEAMER (VS-250)
P/N 1010998 Rev. C 11/12
Technical Theory of Operation
When the Power Switch is on, line voltage flows to the
primary side of the step down transformer. The trans-
former’s secondary side supplies 12 and 24 VAC to the
Control Board.
Once powered, and provided that the Generator’s tem-
perature is below the setpoint temperature, the Control
Board calls for heat by supplying 3 to 5 VDC to the
Solid State Relay terminals 3 (+) 4 (-). Once powered,
the Solid State Relay then closes terminals 1 and 2,
which allows line voltage to flow to the Generator.
As the Generator begins to heat up, a type “K” thermo
-
couple monitors the internal Generator temperature.
As the heat continues to increase, so does the thermo-
couple’s DC millivolts.
Once the Generator’s temperature approaches the
setpoint temperature, the Control Board begins to pulse
the VDC to the Solid State Relay. The Generator’s
VAC and AMPS will also pulse during this point. When
the Generator’s temperature is between the recom-
mended setpoints of 375°F
─
400°F (190°C
─
204°C), the
thermocouple generates approximately 7.5
─8.5 DC mil
-
livolts. The Control Board receives these millivolts and
proceeds to remove the 3
─5 VDC to the Solid State
Relay since the heating circuit has now become satis-
fied.
Then, the Solid State Relay terminals 1 and 2 open up,
and the Generator stops heating. The heating circuit
cycles on and off as needed, even at idle.
When the
SINGLE SHOT
button is pushed, it signals
the Control Board to initiate a single shot of steam. The
Control Board then supplies 24 VAC to the Solenoid
Valve for a split second. The Solenoid Valve opens and
allows approximately 3/4
─
1 ounce (4 to 5 tablespoons)
of water to be disbursed onto the Generator surface
for steaming. The water is immediately converted into
steam, which is forced up through the Black Manifold
Orifices to steam the product within the baskets.
Each of the four
MENU CHANNEL
buttons can be
custom programmed for cycle time, time between when
each steam shot occurs, and water volume used per
each shot (See the Programming section of this manu-
al). An audio signal will sound for three seconds at the
end of the cycle.
If the heating circuit continues to call for heat and the
Generator overheats, a manual resettable Hi-Limit
Thermostat will trip and open the Generator circuit.
NOTE: If any of these conditions should arise, the
root cause must be determined and corrected. See
the Maintenance section of this manual for further
details.
NOTE: All direct water feed units require a Water
Pressure Regulator. It should be set to 20
─
25 psi
(1.4
─
1.7 kg/cm2 or 138
─
172 kPa). Failure to install
a Water Pressure Regulator will result in poor
steaming and flooding of the steam generator.
MAINTENANCE (continued)