PRINCIPLES OF OPERATION
10
is directed into the boiler (or direct-connected steam
control) drain system. Steam inlet lines for compart-
ments are equipped with normally closed solenoid
valves operated by the electrical control circuits. The
inlet valves are opened whenever the compartment
control circuit is activated by use of the 60 minute tim-
ers.
STEAM INLET LINE:
A steam supply line is plumbed from the boiler output
(or direct-connected steam control) to a 1/2 inch barb
fitting connected to the input sides of both steam inlet
solenoid valves. When a cooking compartment is not
in use, the valve for the compartment remains closed
to prevent steam from entering. During operation, the
appropriate inlet solenoid valve is opened by activa-
tion of the control circuit.
Steam is projected onto the surface of pans of food
loaded into the compartment by an orifice located
inside the compartment. Steam continues to flow
through the compartment in this manner until the con-
trol circuit closes the solenoid valve.
STEAM EXHAUST AND DRAIN LINES:
Perforated strainers at the drain line openings inside
each compartment allow only steam, condensation,
and liquid cooking drainage to enter. Prior to dis-
charge into the boiler drain system, steam is convert-
ed to water by the cold water condensing systems for
each compartment.
STEAM EXHAUST CONDENSING SYSTEM:
The steam condensing system consists of the identi-
cal, two-position, normally closed cold water solenoid
valves, with outlet sides connected into the exhaust
plumbing for each cooking compartment. A spray
nozzle directs cold water about the inside of the drain
lines to increase cold water contact with exhausted
steam.
Valve inlet sides are connected remote from the sup-
ply line of the steam boiler (or direct-connected steam
plumbing). The valves respond to a thermostatic
switch located inside the compartment. When the
timer starts the cold water solenoids will energize.
ELECTRICAL CIRCUITS:
The electrical circuits of the cooker control the power
to activate timer motors and energize solenoid-oper-
ated valves and circuits, which in turn control applica-
tion of steam to the cooking compartment and con-
densation of steam from the exhaust line. The cooker
operates on 120V, 2 amp, 60Hz electrical service
connected to all circuits from the circuits of the steam
boiler (or direct-connected steam controls) contained
within the cabinet on which the cooker is mounted.
Power is supplied to the control circuit at all times
when the shut-off device for the unit (supplied by the
user) is in the ON position.
CONTROL CIRCUIT COMPONENTS:
A brief de-
scription of the electrical circuit elements follows.
60 MINUTE TIMER/CONSTANT STEAM:
The timer contains a 120-volt AC synchronous mo-
tor that drives a timing dial through a gear reduction
and clutch mechanism. The timer dial is manually set
for any interval of operation from 0 to 60 minutes or
constant steam as read on the calibrated dial face.
The manual rotation of the dial moves the common
element (1) of the timer switch from the neutral (OFF)
position to contact (3), which connects with the steam
inlet solenoid valve operating circuit.
The cooker is placed into automatic operation with
the setting of the timer dial. Its timing cycle, however,
is automatically delayed by a thermostatic switch,
which assures operating temperature is achieved be-
fore the timer motor begins to “time out.” When the
timer motor has operated for the preset duration, the
common element is transferred to contact (4), return-
ing the inlet solenoid valve to the closed position and
energizing the buzzer. Contact to the buzzer circuit
remains closed until the dial is manually turned to the
OFF position, returning the common element (1) of
the timer switch to the neutral position.
