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F.
Once compartment temperature reaches
approximately 180°F thermal switch
closes and supplies power L1 (HOT) to:
1)
Steam exhaust solenoid valve (N.O.)
energized and closes.
NOTE: Even though steam exhaust
solenoid valve is closed, a small opening
exists in the "guillotine" blade of the valve
to allow "limited free venting" of
condensate during a cook cycle.
2)
Pilot light (red) comes on indicating
timed cooking at 180°F has started.
3)
Timer motor energized
2.
Cooking Timer times down to approximately
one minute before zero.
A.
Micro switch SW2 contacts change state
from N.O. back to N.C. (normal starting
position).
1)
Steam exhaust solenoid valve is de-
energized and opens to exhaust
steam and pressure from the
compartment.
2)
Steam control solenoid (trip) is
energized and unlatches steam
control arm allowing it to return to the
rear. Steam supply the compartment
is shut off.
3.
Cooking timer reaches zero.
A.
Micro switch SW1 contacts change state
from N.O. back to N.C. (normal starting
position).
B.
Buzzer is energized.
4.
Cooking timer is manually turned off.
5.
Compartment power switch is turned OFF,
buzzer is de-energized and power is removed
from the common side of micro switch SW1.
6.
Steamer reverts to preheat cycle until:
A.
A cooking cycle is started. i.e.
compartment door is closed and screw
handle tightened down, time is dialed into
timer (past 5 minutes) and the
compartment power switch is turned ON.
B.
Water level drops below low level cut-off
probes.
C.
Power switch is turned OFF.
NOTE: Heating elements will come back on, after
the boiler pressure drops below the low pressure set
point limit (9 psi) and will stay on until the high
pressure set point (11 psi) is reached. As long as
steam pressure is within limits, even while cooking,
heating elements can go off. The boiler is able to re-
pressurize to the upper set point limit even with all
compartments in cook mode.
VL SERIES STEAMER - ELECTRICAL OPERATION
Page 47 of 88
WATER REFILL (AFTER INITIAL FILL)
1.
Water level drops below low level probe (LL).
A.
Power is removed from terminal 7 on the
differential water level control.
1)
The internal contactor coil is de-
energized returning contacts 3 and 4
back to there original state and
energizing the boiler fill solenoid to
refill the boiler.
2.
Water reaches LL (low level) probe.
A.
Power to terminal 2 on the water level
control is present but no switching occurs.
3.
Water reaches HL (high level) probe.
A.
Power to terminal 10 on the differential
level control.
1)
The internal contactor coil on the
differential level controls is energized.
a.
The normally closed contacts on
terminals 3 and 4 open, de-
energizing the boiler fill solenoid
and the boiler stops filling.
NOTE: The internal contactor coil has a
locking path through contacts on terminals
7 & 8 to the low level probe to keep the
coil energized after the water level drops
below the high level probe.
4.
The water refill cycle will occur whenever the
water level is below the low level probe and will
not affect the operation of either the preheat or
cook cycle.
BOILER BLOWDOWN/DRAIN
1.
Main power switch turned OFF.
A.
Power switch indicator light (red) goes out
and power is removed form all boiler
controls except the blowdown timer.
2.
Blowdown timer switch is pressed.
A.
The normally open timer contacts close,
energizing the blowdown solenoid valve
and the cold water condenser valve.
B.
Boiler begins blowing down and draining
until timer "times out" after approximately
4 minutes.
C.
Timer contacts re-open and power is then
removed from the blowdown solenoid
valve and the cold water condenser valve.
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