JULY 30, 2014
4
3500 SERIES CONVECTION STEAMERS
60 MINUTE TIMER/CONSTANT STEAM
The timer contains a 120-volt AC synchronous motor 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 of the timer switch
from the neutral (OFF) position to contact, which con-
nects 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 auto-
matically delayed by a thermostatic switch, which assures
operating temperature is achieved before the timer motor
begins to “time out.” When the timer motor has operated
for the preset duration, the common element is trans-
ferred 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 manu-
ally turned to the OFF position, returning the common ele-
ment (1) of the timer switch to the neutral position.
DOOR INTERLOCK SWITCH
The interlock switch is a single-pole proximity switch with
normally 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. Con-
nected between the operating contact 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.
THERMOSTATIC SWITCH
The thermostatically operated switch is a two-position,
normally open switch mounted on the cooking compart-
ment. The switch functions to activate the cold water sole-
noid 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.
Figure 1