Vulcan-Hart VL2GPS Boiler User Manual


 
VL SERIES STEAMER - ELECTRICAL OPERATION
Pa
g
e 46 of 88
NOTE: Power the internal contactors on
the low level cut-off and auxiliary low level
cut-off will remain, until the water level
drops below the LLCO probes or the power
switch is turned OFF.
4. Manual reset switch is pressed (momentary).
A. The auxiliary heater contactor is ener
g
ized
supplyin
g
power to the heatin
g
elements
and the heat li
g
ht (amber) comes on.
1) Water in boiler heats up.
B. Internal relay on manual reset switch is
ener
g
ized.
1) Normally open contacts close and
lock to provide power to the auxiliary
heater contactor and the heat li
g
ht
after the reset switch is released.
5. Water reaches LL (low level) probe.
A. Power to terminal 7 on the differential
level control is present but no switchin
g
occurs.
6. Water reaches HL (hi
g
h level) probe.
A. Power to terminal 10 on the differential
level control.
1) The internal contactor coil on the
differential level controls is ener
g
ized.
a. The normally closed contacts on
terminals 3 and 4 open, de-
ener
g
izin
g
the boiler fill solenoid
and the boiler stops fillin
g
.
NOTE: The internal contactor coil has a
lockin
g
path throu
g
h contacts on terminals
7 & 8 to the low level probe to keep the
coil ener
g
ized after the water level drops
below the hi
g
h level probe.
7. Boiler steam pressure reaches upper limit set
point of 11 PSI. (Approximately 15 min.)
A. Cyclin
g
pressure switch opens, heater
contactor(s) de-ener
g
ize and power to the
heatin
g
elements is removed.
NOTE: Steam should not be seen enterin
g
a
compartment until the manual steam control
arm is pulled forward and locked.
8. Boiler steam pressure drops below lower limit
set point of 9 PSI and the cyclin
g
pressure
switch closes.
A. Boiler steam pressure is maintained by the
cyclin
g
of the pressure switch between the
upper and lower set point limits. The
cyclin
g
pressure switch continues to
ener
g
ize and de-ener
g
ize the heatin
g
element contactor(s), which in turn, cycles
the heatin
g
elements on and off. This
sequence continues until one of the
followin
g
occurs:
1) Boiler pressurizes to 15 PSI, causin
g
the hi
g
h limit pressure switch to open.
At that time, the auxiliary heatin
g
element contactor(s) are de-
ener
g
ized, shuttin
g
off power to the
heatin
g
elements. The pressure
switch will remain open until the
pressure drops below the lower limit
set point of 6 PSI. Boiler water level
drops below the LLCO (low water
level cut-off) probes for the low level
cut-off and the auxiliary low level cut-
off controls, de-ener
g
izin
g
the internal
contactor on both controls. This de-
ener
g
izes the main and auxiliary
heater contactors, shuttin
g
off power
to the heatin
g
elements. The heatin
g
elements will remain off 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. Insert product into steamer.
B. Compartment door is closed and screw
handle ti
g
htened down.
C. Compartment steam control arm is pulled
forward and latches, allowin
g
steam to
enter compartment.
NOTE: Cool air and condensate exit throu
g
h
the steam exhaust solenoid valve (N.O.) under
“Full Free Ventin
g
” until the compartment
temperature reaches 180°F. When the solenoid
valve ener
g
izes and closes, condensate will
continue to exhaust throu
g
h a small openin
g
the valve under “Limited Free Ventin
g
” until the
solenoid valve de-ener
g
izes and re-opens, one
minute before the end of a cook cycle.
D. Time is dialed on timer (past 5 minutes).
1) Micro switch SW1 contacts chan
g
e
state from N.C. to N.O.
2) Micro switch SW2 contacts also
chan
g
e state from N.C. to N.O.
E. Compartment power switch is turned ON.
1) L1 (HOT) to one side of the thermal
switch.
NOTE: L2 (NEUTRAL) is connected to the
other side of the buzzer, steam exhaust
solenoid valve, trip solenoid, pilot li
g
ht and
timer motor.