VL SERIES STEAMER - ELECTRICAL OPERATION
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e 43 of 88
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.
A. Power to terminal 9 on the water level
control.
1) LLCO relay ener
izes, LLCO-2 (N.O.)
contacts close and LED li
hts.
B. Power to terminal LLCO on the auxiliary
low water level cut-off control.
1) LLCO relay ener
izes, LLCO-2 (N.O.)
contacts close and LED li
hts.
NOTE: LLCO relays will remain ener
ized
and LLCO LED’S will remain lit until the
water level drops below the LLCO probes
or the power switch is turned OFF.
4. Water reaches LL (low level) probe.
A. Power to terminal 2 on the water level
control is present but no switchin
occurs.
5. Water reaches HL (hi
h level) probe.
A. Power to terminal 6 on water level control.
1) The inverse latchin
relay of the
board is ener
ized, chan
in
the
state of ILR-1 (N.O.) and ILR-2 (N.C.)
contacts. The inverse latchin
relay
will remain ener
ized throu
h the
alternate latchin
path of ILR-1
contacts until the water level recedes
below the low level probe.
2) With ILR-2 contacts open, HL relay is
de-ener
ized, HL-3 (N.O.) contacts
open and HL LED
oes out.
3) Water fill solenoid is de-ener
ized.
(boiler fill time approx. 11 min.)
6. Manual re-set switch is pressed, ener
izin
the
coils on the hi
h limit and low water relays.
A. Contacts 1 & 9 on the hi
h pressure relay
chan
e state and lock from N.C. to N.O.
and turn off the hi
h pressure indicator
li
ht. Concurrently, Contacts 1 & 9 on the
low water relay chan
e state and lock from
N.C. to N.O. and turn off the low water
indicator li
ht.
B. Contacts 5 & 9 on the hi
h pressure relay
chan
e state and lock from N.O. to N.C.,
supplyin
power (NEUTRAL) to one side
of the auxiliary
as solenoid valve.
Concurrently, Contacts 5 & 9 on the low
water relay chan
e state and lock from
N.O. to N.C., supplyin
power (L1) to the
other side of the auxiliary
as solenoid
valve.
NOTE: For both relays to ener
ize, the hi
h
pressure switch must be closed and the water level
in the boiler must be above the low level cut-off
probes in order for LLCO-2 (N.O.) contacts to close.
C. Auxiliary
as solenoid valve is ener
ized
and opens to allow
as flow.
D. As lon
as the i
nition control module is
sensin
a pilot flame, the internal main
valve (MV) contacts close (N.O.) on the
i
nition control module. The main
as
valve is ener
ized and
as be
ins flowin
.
E. Burners li
ht and water in boiler be
ins to
heat up.
7. Boiler steam pressure reaches upper limit set
point of 11 PSI. (Approximately 15 min.)
A. Cyclin
pressure switch opens, main
as
solenoid valve de-ener
izes,
as flow
shuts off and burners
o out.
B. As boiler heats up and builds pressure,
some by-pass water/steam is produced
which runs into the steam drain box. This
causes the cold water condenser (CWC)
solenoid to cycle, coolin
the drain water.
This solenoid is powered by the CWC
thermostat.
NOTE: Steam should not be seen enterin
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
pressure
switch closes.
A. Boiler steam pressure is maintained by the
cyclin
of the pressure switch between the
upper and lower set point limits. The
cyclin
pressure switch continues to
ener
ize and de-ener
ize the main
as
solenoid valve startin
and stoppin
the
flow of
as, which in turn, cycles the
burners on and off. This sequence
continues until one of the followin
occurs:
1) Boiler pressurizes to 15 PSI, causin
the hi
h limit pressure switch to open.
At that time, the auxiliary
as valve
de-ener
izes, shuttin
off the
as
flow to the burners and the hi
h limit
failure li
ht will come on. This li
ht
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-ener
izes the LLCO
relays, chan
in
the contact state of
LLCO-2 (N.O.) back to open. This de-
ener
izes the main and auxiliary
as
solenoid valves. The
as solenoid
valves will remain off and the low
water level li
ht will come on and stay
lit until the water level rises above the
LLCO probes and the manual re-set
switch is pressed.
