VSX SERIES STEAMER - ELECTRICAL OPERATION
Page 34 of 80
SEQUENCE OF OPERATION
GAS MODELS
This sequence of operation is written for steamers
with automatic ignition, solid state water level
controls and the CSD-1 (code) option. Refer to
schematic diagram number 3707.
INITIAL FILL AND PREHEAT
1. Conditions.
A. Power switch OFF.
B. Ignition module reset switch ON
C. Doors shut (closes the N.O. door switch
contacts).
D. Cooking timers OFF.
E. Unit connected to correct voltage
(120VAC).
1) L1 to one side of the cooking
compartment pressure switch (N.O.),
then to the other compartment
controls; to one side of the cold water
condenser thermostat; to one side of
the power ON/OFF switch.
2) NEUTRAL to one side of the cooking
compartment controls; to one side of
the cold water condenser (CWC)
solenoid valve; to one side of the
power ON/OFF switch.
F. Unit properly grounded. (Boiler and water
level control share a common ground)
G. Water supply valve on.
H. Gas supply valve on.
I. Gas combination control valve on.
J. Control (cycling) pressure switch closed.
K. High limit pressure switch closed.
L. Cold water condenser (CWC) thermostat
open.
M. Blowdown solenoid valve (drain) open and
boiler empty.
2. Power switch turned ON. (located on boiler
control box)
A. Power switch indicator light (red) comes
on.
B. Hi pressure indicator light (amber) comes
on.
C. Low water level indicator light (amber)
comes on.
NOTE:
The high pressure indicator light will remain
on and the safety circuit de-energized until boiler
steam pressure is within operational limits (high limit
pressure switch closed) and the manual reset button
is pressed. The low water indicator light will remain
on and the safety circuit de-energized until the water
level in the boiler reaches the low level cut-off
probes (minimum level) for the water level control,
the auxiliary low level cut-off control and the manual
reset switch is pressed. The gas burners will not
light until these conditions are satisfied.
D. Water level control (WLC) is powered.
1) High level (HL) relay is energized,
HL-3 (N.O.) contacts close and HL
LED lights up.
2) The inverse latching relay of the
board remains de-energized, leaving
the ILR-1 (N.O.) and ILR-2 (N.C.)
contacts in their shelf state.
E. Auxiliary low water level cut-off control is
powered, LLCO-2 (N.O.) contacts remain
open.
F. With the HL-3 and ILR-2 contacts closed,
the fill solenoid is energized and water
boiler begins filling.
G. Blowdown solenoid valve is energized and
closes.
H. Ignition module begins sparking to light
pilot after a 3 second delay.
1) If pilot ignition is established (pilot lit)
then a micro amp flame sense
current is sent back to the ignition
control module through the ignition
cable. Sparking stops, pilot remains
lit and is ready to ignite burners.
2) If pilot ignition is not established after
90 seconds, sparking stops and the
ignition control module locks out
power to the combination gas valve
(pilot valve and main valve remain
closed). The module remains locked
out until the reset switch on the
ignition control module box is
switched to off then on to re-start the
ignition trial cycle.
NOTE:
If the modules re-set switch is in the off
position, no sparking will occur or if it’s turned off
while in ready or cook mode then pilot and burners
will go out and not re-ignite upon call for heat by the
cycling pressure switch.
3. Water level reaches LLCO (low water level cut-
off) probe for the water level control and to the
auxiliary LLCO probe for the auxiliary low level
cut-off control.
