VL SERIES STEAMER - ELECTRICAL OPERATION
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
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
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.
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
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