Vulcan-Hart VSX Series Service Manual page 36

A. Boiler steam pressure is maintained by the
cycling of the pressure switch between the
upper and lower set point limits. The
cycling pressure switch continues to
energize and de-energize the main gas
solenoid valve starting and stopping the
flow of gas, which in turn, cycles the
burners on and off. This sequence
continues until one of the following occurs:
1) Boiler pressurizes to 15 PSI, causing
the high limit pressure switch to open.
At that time, the auxiliary gas valve
de-energizes, shutting off the gas
flow to the burners and the high limit
failure light will come on. This light
will stay lit until the pressure drops
below the lower limit set point of 6
PSI and the manual re-set switch is
pressed.
2) Boiler water level drops below the
LLCO probes for the water level and
the auxiliary low level cut-off controls
which then de-energizes the LLCO
relays, changing the contact state of
LLCO-2 (N.O.) back to open. This de-
energizes the main and auxiliary gas
solenoid valves. The gas solenoid
valves will remain off and the low
water level light will come on and stay
lit until the water level rises above the
LLCO probes and the manual re-set
switch is pressed.
COOK CYCLE
1. A Cook cycle should not be started, until the
initial fill and preheat is completed, in order for
the boiler steam pressure to be within
operational limits.
A. Ready light (green) is lit.
B. Product is inserted into steamer.
C. Door is closed.
D. Timer is dialed on timer.
2. Contacts 1/3 of cook timer close.
A. Ready light (green) goes out.
B. Cooking light (red) comes on.
C. Timer motor is energized.
D. Compartment steam solenoid valve
energized and steam begins to enter the
compartment.
VSX SERIES STEAMER - ELECTRICAL OPERATION
Page 36 of 80
NOTE: Burners will re-light after the boiler pressure
drops below the low pressure set point limit (8 psi)
and will stay on until the high pressure set point (10
psi) is reached. As long as steam pressure is within
limits, even while cooking, burners can go off. The
boiler is able to re-pressurize to the upper set point
limit even with both compartments in cook mode.
NOTE: The cold water condenser thermostat
remains closed and cold water condenser solenoid
stays energized while cooking. If main water is shut
off after boiler fill, then no cold water is present to
condense steam/hot water and steam vapors exit
the floor drain.
3. Time expires on timer.
A. Timer contacts 1/3 open.
B. Steam solenoid valve de-energized,
stopping the flow steam into compartment.
C. Cooking light goes out.
D. Timer contacts 4/1 close and energize
buzzer until manually turned off.
E. Ready light (green) comes on.
F. Timer motor de-energized.
4. Timer manually turned off.
A. Contacts 1/4 open
B. Alarm Buzzer de-energized and stops
buzzing.
5. Steamer reverts to preheat cycle until time is
dialed into timer and the door is shut, water
level drops below low level cut-off probe or the
power switch is turned off.
WATER REFILL (AFTER INITIAL FILL)
1. Water level drops below low level probe (LL).
A. Power is removed from terminal 2 on the
water level control .
1) The inverse latching relay is de-
energized, returning ILR-1 (N.O.) and
ILR-2 (N.C.) contacts back to their
original state.
B. HL relay is energized.
1) Contacts HL-3 close.
2) HL LED comes on.
3) Fill solenoid is energized and water
flows into tank.
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 high level probe.