Table of Contents
Advertisement
SECTION 4 PRINCIPLES OF OPERATION
When the timer motor has operated for the preset
duration, the common element is transferred to contact (4),
returning 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.
4.3.1.2 Indicator Lights
An indicator light is included for the compartment. The light
remains on (red) at all times when the coinciding timer dial
is set and the door interlock switch is closed. The light
turns off at the end of the timed cooking duration or when
the set time has elapsed.
4.3.1.3 Buzzer
The buzzer is an alarm device that operates by oscillation
of a striker against the core of an electromagnet. When the
60-minute timer dials reach the "0-Minute" position, the
buzzer coil is energized to sound the buzzer. Movement of
the timer dial to the OFF position opens the contact to the
buzzer coil to shut it off.
4.3.1.4 Door Interlock Switch
The interlock switch is a single-pole proximity switch with
normally open contacts. The switch is operated by the nor-
WATER INLET TO
TOP CAVITY
STEAM JET PIPE
(2 PER COMPARTMENT)
STEAM LINE
TO CAVITY
WATER INLET
FROM BOILER
Figure 4-1 Pictorial Diagram, Steam & Water Circuits (Model ST-20 Shown Here)
mally open contacts. The switch is operated by the
proximity of a magnet within the door. When the door is
open, the switch contacts remain in the open position.
When the door is closed and securely latched in place, the
magnet is near the switch to close the contacts.
Connected between the operating contact (3) of the timers
and the steam inlet solenoid valve, the door switch acts as
a protective device to interrupt valve operation unless the
door is closed.
4.3.1.5 Thermostatic Switch
The thermostatically operated switch is a two-position,
normally
open
switch
compartment. The switch functions to activate the cold
water solenoid valves of the steam condensing system
and to delay timer motor operation until the compartment
temperature reaches 195°F, thus assuring that cooking
temperature exists throughout the timed duration.
4.3.1.6 Digital Timers (Optional)
The timer controls the steam to the cavity by either a
constnat steam setting or a used defined timer that will be
programmed by the user into the timer
4-2
WATER TO
DRAIN LINE
STEAM LINE
TO CAVITY
STEAM LINE
FROM BOILER
mounted
on
the
cooking
Advertisement
Table of Contents
