Vulcan-Hart VL Series User manual

A product of VULCAN-HART LOUISVILLE, KY 40201-0696
F24650 Rev. A (1017)
- NOTICE -
This Manual is prepared for the use of trained Vulcan Service
Technicians and should not be used by those not properly
qualified. If you have attended a Vulcan Service School for this
product, you may be qualified to perform all the procedures
described in this manual.
This manual is not intended to be all encompassing. If you have
not attended aVulcan ServiceSchool forthisproduct, you should
read, in its entirety, the repair procedure you wish to perform to
determine if you have the necessary tools, instruments and skills
required to perform the procedure. Procedures for which you do
not have the necessary tools, instruments and skills should be
performed by a trained Vulcan Service Technician.
Reproduction or other use of this Manual, without the express
written consent of Vulcan, is prohibited.
VL2GPS SHOWN
SERVICE MANUAL
VL BOILER BASE SERIES
CONVECTION STEAMERS
(GAS, ELECTRIC, DIRECT AND REGENERATED)
VL2GPS ML-52391 VL2DPS ML-52749
VL2GMS ML-52388 VL2DMS ML-52750
VL2GAS ML-52390 VL2DAS ML-52751
VL2GSS ML-52389 VL2DSS ML-52752
VL3GPS ML-52395 VL3DPS ML-52753
VL3GMS ML-52392 VL3DMS ML-52754
VL3GAS ML-52394 VL3DAS ML-52755
VL3GSS ML-52393 VL3DSS ML-52756
VL2EPS ML-52741 VL2RPS ML-52757
VL2EMS ML-52742 VL2RMS ML-52758
VL2EAS ML-52743 VL2RAS ML-52759
VL2ESS ML-52744 VL2RSS ML-52760
VL3EPS ML-52745 VL3RPS ML-52761
VL3EMS ML-52746 VL3RMS ML-52762
VL3EAS ML-52747 VL3RAS ML-52763
VL3ESS ML-52748 VL3RSS ML-52764

VL BOILER BASE SERIES CONVECTION STEAMERS
F24650 Rev. A (1017) Page 2 of 93
Text Text

TABLE OF CONTENTS
GENERAL .................................................................................................. 5
INTRODUCTION ....................................................................................... 5
WATER CONDITIONING ............................................................................... 5
TOOLS ................................................................................................. 6
SPECIFICATIONS ...................................................................................... 6
STEAMER OPERATION ................................................................................ 8
COMPONENT FUNCTION ............................................................................ 11
REMOVAL AND REPLACEMENT OF PARTS .............................................................. 15
COMPONENT LOCATIONS ........................................................................... 15
WATER LEVEL CONTROLS - LOW LEVEL CUT OFF AND DIFFERENTIAL ............................ 17
WATER LEVEL GAUGE ASSEMBLY .................................................................. 17
CYCLING AND HIGH LIMIT PRESSURE SWITCHES (GAS AND ELECTRIC MODELS) ................ 18
BOILER ASSEMBLY .................................................................................. 18
HIGH LIMIT THERMOSTAT ........................................................................... 19
BOILER FILL AND COLD WATER CONDENSER SOLENOID VALVES ................................. 19
PILOT AND THERMOCOUPLE ASSEMBLY (GAS MODELS) .......................................... 19
GAS COMBINATION CONTROL VALVE ............................................................... 20
COMPARTMENT GASKET AND DOOR SCREW NUT, DOOR AND BUSHINGS ........................ 20
HEATER CONTACTORS .............................................................................. 21
HEATING ELEMENTS ................................................................................ 21
REGENERATED STEAM MODELS (STEAM COIL) .................................................... 22
SERVICE PROCEDURES AND ADJUSTMENTS ........................................................... 23
BOILER ............................................................................................... 23
WATER LEVEL CONTROL(S) TEST ................................................................... 25
CYCLING AND HIGH LIMIT PRESSURE SWITCHES (GAS AND ELECTRIC MODELS) ................ 27
FILL AND COLD WATER SOLENOID VALVES ........................................................ 28
COMPARTMENT PRESSURE ADJUSTMENT ......................................................... 28
HIGH LIMIT THERMOSTAT ........................................................................... 29
BOILER NOT FILLING WITH WATER .................................................................. 29
BOILER BLOWDOWN DRAIN SOLENOID VALVE ..................................................... 30
BOILER SLOW TO PRESSURIZE ..................................................................... 30
INLET WATER STRAINER ............................................................................ 32
PILOT AND THERMOCOUPLE ASSEMBLY (GAS MODELS) .......................................... 32
GAS BURNERS ....................................................................................... 34
AUTOMATIC IGNITION SYSTEMS (GAS MODELS) ................................................... 35
GAS MANIFOLD PRESSURE ADJUSTMENT .......................................................... 37
DIRECT STEAM MODELS ............................................................................ 38
REGENERATED STEAM (OLDER MODELS) .......................................................... 38
HEATER CONTACTORS .............................................................................. 38
HEATING ELEMENTS ................................................................................ 39
THERMAL SWITCH - PREVENT AND AUTOMATIC MODELS ......................................... 40
WATER LEVEL GAUGE ASSEMBLY .................................................................. 41
STEAM GATE VALVE(S) .............................................................................. 41
ELECTRICAL OPERATION ................................................................................ 43
WATER LEVEL CONTROLS .......................................................................... 43
SEQUENCE OF OPERATION ......................................................................... 46
SCHEMATICS, GAS STEAMERS, BOILER CONTROLS VL2G AND VL3G -
PREVENT, AUTOMATIC, STANDARD AND MANUAL ............................................. 54
WIRING DIAGRAMS, GAS STEAMERS, BOILER CONTROLS VL2G AND VL3G -
PREVENT, AUTOMATIC, STANDARD AND MANUAL ............................................. 59
SCHEMATICS, ELECTRIC STEAMERS, BOILER CONTROLS VL2E AND VL3E -
PREVENT, AUTOMATIC, STANDARD AND MANUAL ............................................. 67
WIRING DIAGRAMS, ELECTRIC STEAMERS, BOILER CONTROLS VL2E AND VL3E
- PREVENT, AUTOMATIC, STANDARD AND MANUAL ............................................ 69
VL BOILER BASE SERIES CONVECTION STEAMERS
Page 3 of 93 F24650 Rev. A (1017)

WIRING DIAGRAMS, ELECTRIC HEATER CIRCUITS VL2E AND VL3E - PREVENT,
AUTOMATIC, STANDARD AND MANUAL ......................................................... 81
SCHEMATIC AND WIRING DIAGRAMS, DIRECT STEAMERS, CABINET BASE VL2D
AND VL3D - PREVENT, AUTOMATIC, STANDARD AND MANUAL ................................. 82
WIRING DIAGRAMS, REGENERATED STEAMERS, BOILER CONTROLS VL2R
AND VL3R - PREVENT, AUTOMATIC, STANDARD AND MANUAL ................................. 83
SCHEMATIC AND WIRING DIAGRAMS - COMPARTMENT CONTROLS ............................... 85
TROUBLESHOOTING ..................................................................................... 89
ALL MODELS ......................................................................................... 89
GAS MODELS ONLY .................................................................................. 92
VL BOILER BASE SERIES CONVECTION STEAMERS
© VULCAN 2017
F24650 Rev. A (1017) Page 4 of 93

GENERAL
INTRODUCTION
Steam Cooking
Large capacity pressure steamers offer an efficient
way to produce a wide variety of foods in small
portions or larger batches. Steamers can be used to
cook fresh foods, blanch foods for complete cooking
later or will steam defrost and cook frozen foods.
Cooking with steam assures the food will retain its
maximum color, flavor and nutritional value with the
least expenditure of energy and labor.
Compartment Pan Capacity
PANS PER
COMPARTMENT SIZE DEPTH (INCHES)
4 12" x 20" 6
6 12" x 20" 4
8 12" x 20" 2.5
6 *18" x 20" 1
* Remove center support for 18"x20" inch pans
Model Designations
Boiler Code Descriptions
Vulcan-Hart incorporates redundant controls in
compliance with California Code (Cal-Code) and
CSD-1 as an option on steam equipment when
required by state and/or local building code
requirements. Descriptions of the codes are listed
below.
Cal-Code Construction - Redundant controls in the
electrical safety circuits that, if tripped, must manually
be reset after the condition causing the trip subsides.
These controls consist of one dual function water level
cycling and low level cut off control and one single
function low water level cutoff control (Aux - LLCO)
and a high pressure relief switch in conjunction with a
mechanical pressure relief valve.
CSD-1 Construction - Redundant controls in the
electrical safety circuits that, if tripped, must manually
be reset after the condition causing the trip subsides.
These controls consist of one dual function water level
cycling and low level cut off control and one single
function low water level cutoff control (LLCO) and a
high pressure relief switch in conjunction with a
mechanical pressure relief valve. Additionally, both
circuits have individual indicator lights that will
illuminate for a visual verification of the shutdown
mode.
Cal-Code and CSD-1 construction both require
operator intervention in the event of a shutdown.
CSD-1 is more informative by using indicator lights to
show which safety system was shut down.
WATER CONDITIONING
Furnishing the boiler with soft water to reduce scale
formation is important. Scale formation will reduce
steam output, cause premature component failure,
and shorten equipment life. Most water supplies
contain scale producing minerals such as calcium and
magnesium. As steam is generated, the minerals
remain and dissolve into the water. As the
concentration of these minerals increases past a
certain point, they precipitate from the water and coat
the inside of the boiler, heating elements, thermostat
bulbs and water level probes. Because of the high
temperature of these surfaces, the precipitated
minerals bake onto them and become very difficult to
remove.
This causes several problems:
1. Reduction in heat transfer efficiency of the
heating system.
2. Premature failure of electric heaters.
3. False readings by water level probes.
4. Thermostat bulbs will sense temperature
incorrectly.
These problems are common to any manufacturer's
steamer regardless of design, but they can all be
prevented by furnishing the boiler with soft water.
Vulcan recommends the water contain less than 60
ppm of “total dissolved solids” (TDS) and have a PH
factor between 7 to 8. These water properties can be
VL BOILER BASE SERIES CONVECTION STEAMERS - GENERAL
Page 5 of 93 F24650 Rev. A (1017)

achieved by using a properly maintained water
softener.
Other chemical properties in water supplies can also
affect good steam generation and vary from within
each state and locality.
The water level probes in the boiler use ions in the
water to detect the water level. Do not use fully
demineralized or deionized water since it is
"nonconductive" and the water level cannot be
detected.
NOTE: The use of strainers, or filters will not remove
minerals from the water.
Vulcan recommends that a local water treatment
specialist be consulted before the installation of any
steam generating equipment. Steamers that operate
over a long period of time without the benefit of a water
softener, which have developed a heavy scale
buildup, should be cleaned before using a water
softener.
Steamers that operate over a long period of time
without the benefit of a water softener, which have
developed a heavy scale build up, should be cleaned
before using a water softener.
TOOLS
Standard
• Standard set of hand tools.
• Volt-Ohm-Meter (VOM) with AC current tester.
(Any quality VOM with a sensitivity of at least
20,000 ohms per volt can be used)
• Gas leak checking equipment.
• Gas pressure manometer.
• Temperature meter and thermocouple.
Special
• CLR Treatment Kit - Used to remove Calcium/
Lime/Rust from a boiler (Contact Vulcan
Authorized Service Centers)
• Adaptor to test thermocouple closed circuit
voltages (DC) on gas models with manual
ignition (purchase locally).
NOTE: Adaptors vary between manufacturers. An
example of one adaptor type is pictured below.
Fig. 2
SPECIFICATIONS
Water Supply
Supply pressure should be 20-80 psig
In line strainer for supply line (Not Supplied)
Supply connection cold
Total dissolved solids
(TDS)* less than 60 ppm
Total alkalinity less than 20 ppm
Silica less than 13 ppm
Chloride less than 30 ppm
PH factor 7 to 8
(*17.1 ppm = 1 grain of hardness)
Steam Supply
Dry steam must be provided to the steamer for
suitable use. If the steam is heavy with condensate, a
Ball Float Trap must be used in the line and plumbed
in before the pressure reducing valve. To ensure rapid
heat up of heavy cold loads, the steam supply line
must be sized to maintain pressure as outlined below.
DIRECT STEAM
STEAMERS
(POTABLE)
REGENERATED
STEAMERS -
OLDER MODELS
(*NON-
POTABLE)
Supply
Pressure
Input
15 psi (min.) 15 psi (min.)
Flow Rate 50 lb. per hour
per compartment 125 lb. per hour
Pressure
Reducing
Valve Output
10 psi
(furnished)
set accordingly for
good steam
generation (10- 12
psi)
*Potable steam is not required for regenerated
models but could be used.
VL BOILER BASE SERIES CONVECTION STEAMERS - GENERAL
F24650 Rev. A (1017) Page 6 of 93

Gas Steamers
Electric Steamers
AMPERAGE
1 PHASE 3 PHASE 3 PHASE - 4 WIRE
MODEL TOTAL
KW 208V 240V 208V 240V 480V 220/380V & 240/415V
VL2EPS
24* 116 100 67 58 29 34
36 100 87 44 50
42 117
48 116 58 67
VL2EMS
24* 116 100 67 58 29 34
36 100 87 50
42 117
48 116 58 67
VL2ESS
24* 116 100 67 58 29 34
36 100 87 44 50
42 117
48 116 58 67
VL2EAS
24* 116 100 67 58 29 34
36 100 87 44 50
42 117
VL BOILER BASE SERIES CONVECTION STEAMERS - GENERAL
Page 7 of 93 F24650 Rev. A (1017)

AMPERAGE
1 PHASE 3 PHASE 3 PHASE - 4 WIRE
MODEL TOTAL
KW 208V 240V 208V 240V 480V 220/380V & 240/415V
48 116 58 67
*Standard
STEAMER OPERATION
Ensure that all utility connections to the steamer have
been made and are turned on.
On models that are CSD-1 equipped, amber colored
lights for high pressure and low water level will
illuminate and stay on until the boiler is full and the
manual reset switch pressed.
Gas Powered Steam Boiler
Open the cabinet door and turn main power switch
ON. The red light will illuminate, water will begin filling
the boiler and the blowdown solenoid valve will close.
The boiler should fill in four to eleven minutes.
Observe water level gauge glass to verify that water
is in boiler and that the level in the gauge glass is about
half full. Both valves on gauge glass assembly must
be open to fill the gauge. Older models equipped with
a manual “ball” type blowdown valve must be closed
for the boiler to fill. The cycling pressure switch will
maintain the proper steam pressure in the boiler by
cycling the heating system on and off to generate
steam pressure.
1. On Models with Manual Ignition - The knob on the
gas combination control valve has three
positions (On-Pilot-Off) for control of main
burners and pilot. Turn knob on gas combination
valve to PILOT then depress and light pilot burner
with a lit taper. Maintain knob in depressed
position for about 30 seconds and release.
Observe that pilot burner flame stays on. If the
flame should go out, wait 5 minutes before
relighting. Turn knob on gas combination control
valve to ON. If the water level in the boiler has
reached the minimum level, burners will ignite
and begin to heat the water in the boiler. After
approximately 15 minutes, steam should be
present for cooking product. Observe that the
boiler pressure gauge indicates steam pressure
of 9-11 psi for models with a pressure regulating
valve or 4-6 psi for models without the valve.
2. On Models with Automatic Ignition - The knob on
the gas combination control valve has two
positions (On-Off) for control of main burners and
pilot. For the automatic ignition system to work,
the knob must be set in the ON position or gas
for the pilot and main burners will not flow. Also,
the ignition control module ON/OFF/RESET
switch must be in the ON position to operate. This
switch is located on the upper left side of the
electrical control box for the ignition control
module. A red light will illuminate when the switch
is in the ON position. DO NOT ATTEMPT TO
MANUALLY LIGHT THE PILOT IN AN
AUTOMATIC TYPE IGNITION SYSTEM.
After the main power switch is turned ON and the
ignition control modules RESET switch is in the
ON position, sparking will begin three seconds
later to light the standing pilot. If the pilot lights, a
signal is sent back through the ignition cable
indicating the presence of pilot flame and
sparking stops. If the water level in the boiler has
reached the minimum level, the burners will ignite
and begin to heat the water in the boiler. After
approximately 15 minutes, steam should be
present for cooking product. Observe that the
boiler pressure gauge indicates a steam
pressure of 9-11 psi for models with a pressure
regulating valve or 4-6 psi for models without the
valve. If a pilot flame is not established
immediately, sparking will continue for 90
seconds. After that duration, the ignition control
module will lock out, and will need to be reset to
start the pilot and burner lighting cycle again.
Electrically Powered Steam Boiler
Open the cabinet door and turn main power switch
ON. The red light will illuminate, water will begin filling
the boiler and the blowdown solenoid valve will close.
The boiler should fill in approximately 11 minutes.
Observe water level gauge glass to verify that water
is in boiler and that the level in the gauge glass is about
half full. Both valves on gauge glass assembly must
be open to fill the gauge. Older models equipped with
a manual “ball” type blowdown valve must be closed
for the boiler to fill. If the water level in the boiler has
reached the minimum level, the heater contactors will
close, the heaters will energize and begin to heat the
VL BOILER BASE SERIES CONVECTION STEAMERS - GENERAL
F24650 Rev. A (1017) Page 8 of 93

water in the boiler. After approximately 15 minutes,
steam should be present for cooking product. Observe
that the boiler pressure gauge indicates steam
pressure of 9-11 psi for models with a pressure
regulating valve or 4-6 psi for models without the
valve.
Regenerated Steam Powered Boiler
Open the cabinet door and turn main power switch
ON. The pilot light will illuminate, water will begin filling
the boiler and the blowdown solenoid valve will close.
Models equipped with a manual “ball type” blowdown
valve need to be closed for the boiler to fill. The boiler
should fill in approximately 15 minutes.
Observe water level gauge glass to verify that water
is in boiler and that the level in the gauge glass is about
half full.
Both valves on the gauge glass assembly must be
open to fill the gauge. When the water reaches the
minimum level, the steam solenoid valve will open,
allowing steam to enter the steam coil in the heat
exchanger tank and begin heating the water. After
approximately 20 minutes, a sufficient amount of
pressurized steam should be present for cooking
product.
Direct Steam Powered Cooker
1. Open the cabinet door and turn main power
switch ON.
A. The red light on the switch will illuminate.
B. If steam pressure is above the minimum
setting on the cooking compartment
pressure switch then the switch will close,
ready light will come ON and power to the
other controls will be supplied.
C. Observe that the steam pressure gauge in
the cabinet base indicates 10-12 psi.
2. Steamer is ready to cook product.
Boiler Blowdown and Steamer Shut off
Turn the steamer off at least once daily and blow down
the boiler to remove sediments, scalants and lime
build-up in the boiler. Always blowdown the boiler
when it is under maximum pressure and no steam is
being used.
1. Automatic blowdown
A. Newer Models - Open the cabinet door and
turn main power switch OFF. The switch's
red light will go out, the blowdown/drain
solenoid valve will be deenergized and the
boiler will begin to drain. The cold water
condenser solenoid will continue to operate,
as needed, to condense steam and to cool
the water going into the drain.
B. Older Models - Turn power switch OFF and
depress blowdown timer button. Blowdown
timer will operate for 4 minutes. At the end
of blowdown, turn fill switch ON and allow
boiler to fill.
2. Manual blowdown
A. All Models - Turn power switch OFF. Open
blowdown valve located on the bottom front
of the cabinet base. After the boiler has
completely drained, close blowdown valve
and turn fill switch to ON and allow boiler to
fill.
Cooking Compartment Controls
Close the compartment door and turn the screw
handle clockwise until the gasket touches the
compartment surface then ½ turn further to
adequately seal the compartment. If steam leaks
occur after compartment heat up and pressurization,
turn handle clockwise again to increase the sealing
force until the leak stops.
Proceed to the cooking compartment control
instructions that apply to the steamer in use.
1. Manual
A. Set the manual timer to the desired cooking
time. If preheating is desired, allow five to
ten minutes (recommended) of additional
time at the beginning of the cook cycle. The
length of time will vary with the type, size,
temperature and condition (frozen or
thawed) of the product and must be
determined from experience. Pull the steam
control arm handle forward and lock it by
pulling the handle down. This closes the
steam exhaust gate valve and opens the
steam inlet gate valve, allowing steam to
enter the compartment. During preheat,
cooler air and condensate are exhausted
from the compartment through the steam
trap (condenser) until the temperature
reaches 180°F, closing the internal bellows.
Throughout the cooking cycle, the
compartment pressure should be 6 psi if
VL BOILER BASE SERIES CONVECTION STEAMERS - GENERAL
Page 9 of 93 F24650 Rev. A (1017)

equipped with a compartment pressure
regulating valve. On models without the
compartment pressure regulating valve, the
compartment pressure cycles with the boiler
pressure between 4 and 6 psi.
B. When the timer bell rings to signal the end
of a cook cycle, turn it OFF. Lift the steam
control arm handle to unlatch team control
arm. An internal spring will automatically pull
the arm to the rear. This closes the steam
inlet gate valve and opens the steam
exhaust gate valve, allowing steam and
pressure to exit the compartment.
C. Wait approximately 30 seconds for the
steam to exhaust from the compartment and
to depressurize. Turn the screw handle on
the compartment door counterclockwise
until the gasket no longer seals against the
compartment surface. After the remaining
steam escapes, move the latch paddle to
the left and open the door.
2. Standard
A. Set the timer to the desired cooking time.
The timer must be set past five minutes to
change the state of the timer control micro
switch contacts. If preheating is desired,
allow five to ten minutes (recommended) of
additional time at the beginning of the cook
cycle. The length of time will vary with the
type, size, temperature and condition
(frozen or thawed) of the product and must
be determined from experience.
B. Pull the steam control arm handle forward
and lock it by pulling the handle down. This
closes the steam exhaust gate valve and
opens the steam inlet gate valve, allowing
steam to enter the compartment.
C. Press the compartment power switch to
energize the timer and red light. The
balance of the cooking sequence is
automatic. During preheat, cooler air and
condensate are exhausted from the
compartment through the steam trap
(condenser) until the temperature reaches
180°F, closing the internal bellows.
Throughout the cooking cycle, the
compartment pressure should be 6 psi if
equipped with a compartment pressure
regulating valve. On models without the
compartment pressure regulating valve, the
compartment pressure cycles with the boiler
pressure between 4 and 6 psi.
D. Approximately one minute before timer
reaches zero, the steam control solenoid is
energized to unlatch the steam control arm.
An internal spring will automatically pull the
arm to the rear. This closes the steam inlet
gate valve and opens the steam exhaust
gate valve, allowing steam and pressure to
exit the compartment. When the timer
reaches "0" the red light shuts off and a
buzzer sounds indicating the end of the
cook cycle. Turn the compartment power
switch OFF to silence the buzzer and
remove power from the compartment
controls.
E. Turn the screw handle on the compartment
door counterclockwise until the gasket no
longer seals against the compartment
surface. After the remaining steam escapes,
move the latch paddle to the left and open
the door.
3. Automatic
A. Set the timer to the desired cooking time.
The timer must be set past five minutes to
change the state of the timer control micro
switch contacts.
B. Pull the steam control arm handle forward
and lock it by pulling the handle down. This
closes the steam exhaust gate valve and
opens the steam inlet gate valve, allowing
steam to enter the compartment.
C. Press the compartment power switch to
supply power to the compartment controls.
The automatic compartment controls
feature load compensated cooking time by
utilizing a thermal switch. With this feature,
when the compartment temperature
reaches 180°F (the temperature at which
preheating or defrosting is complete) the red
light will then come on and the timer will
start. For a small food load, the delay time
before the timer starts might be a minute or
less. For a large food load, the delay time
could be four to five minutes. During
preheat, cooler air and condensate are
exhausted from the compartment through
the steam trap (condenser) until the
temperature reaches 180°F, closing the
internal bellows. Throughout the cooking
cycle, the compartment pressure should be
6 psi if equipped with a compartment
VL BOILER BASE SERIES CONVECTION STEAMERS - GENERAL
F24650 Rev. A (1017) Page 10 of 93

pressure regulating valve. On models
without the compartment pressure
regulating valve, the compartment pressure
cycles with the boiler pressure between 4 to
6 psi.
D. Approximately one minute before timer
reaches zero, the steam control solenoid is
energized to unlatch the steam control arm.
An internal spring will automatically pull the
arm to the rear. This closes the steam inlet
gate valve and opens the steam exhaust
gate valve, allowing steam and pressure to
exit the compartment. When the timer
reaches "0" the red light shuts off and a
buzzer sounds indicating the end of the
cook cycle. Turn the compartment power
switch OFF to silence the buzzer and
remove power from the compartment
controls.
E. Turn the screw handle on the compartment
door counterclockwise until the gasket no
longer seals against the compartment
surface. After the remaining steam escapes,
move the latch paddle to the left and open
the door.
4. Prevent
A. Set the timer to the desired cooking time.
The timer must be set past five minutes to
change the state of the timer control micro
switch contacts.
B. Pull the steam control arm handle forward
and lock it by pulling the handle down. This
opens the steam inlet gate valve, allowing
steam to enter the compartment.
C. Press the compartment power switch to
supply power to the compartment controls.
The prevent compartment controls feature
load compensated cook times by utilizing a
thermal switch. With this feature, when the
compartment temperature reaches 180°F
(the temperature at which preheating or
defrosting is complete) the red light will
come on and the timer will start. For a small
food load, the delay time before the timer
starts might be a minute or less. For a large
food load, the delay time could be four and
five minutes. During preheat, the steam
exhaust solenoid valve (N.O.) is open to
allow the full free venting of cooler air and
condensate from the compartment. When
the temperature reaches 180°F, the exhaust
solenoid valve is energized and closes. The
compartment should then pressurize to 6
psi.
D. Approximately one minute before timer
reaches zero, the steam control solenoid is
energized to unlatch the steam control arm.
An internal spring will automatically pull the
arm to the rear. This closes the steam inlet
gate valve and opens the steam exhaust
gate valve, allowing steam and pressure to
exit the compartment. When the timer
reaches "0" the red light shuts off and a
buzzer sounds indicating the end of the
cook cycle. Turn the compartment power
switch OFF to silence the buzzer and
remove power from the compartment
controls.
E. Turn the screw handle on the compartment
door counterclockwise until the gasket no
longer seals against the compartment
surface. After the remaining steam escapes,
move the latch paddle to the left and open
the door.
COMPONENT FUNCTION
CABINET BASE BOILER CONTROLS
Water Level Gauge
Assembly .............
Permits a visual confirmation the water level is being maintained in boiler during
operation. The correct water level is a point one-half of the height of the glass. The manual
valves at the top and bottom of this assembly must be fully open and only closed if the
glass tube is damaged.
Water Level Control
and Level Sensing
Probes ................
These controls allow water to enter the boiler to fill and maintain the proper water level.
They will also shut off the heat source to the boiler if the water level drops too low. The
VL BOILER BASE SERIES CONVECTION STEAMERS - GENERAL
Page 11 of 93 F24650 Rev. A (1017)

water level control works by using three different probe lengths to monitor the water level.
The probes consist of a high level (HL), low level (LL) and low water cut-off (LLCO).
Boiler Fill Solenoid
Valve .................
Admits water to the boiler when demanded by the water level control to maintain the
correct water level in the boiler.
Cold Water Condenser
Solenoid Valve .......
Allows cold water flow into the boiler blowdown drain box to condense steam and cool
the hot water before its discharge into the drain.
Cycling Pressure
Switch ................
Controls boiler pressure between prescribed limits by turning the heat source on and off.
High Limit Pressure
Switch ................
A switch of identical design to the cycling pressure switch but used as a high limit. The
pressure settings are at higher and lower limits than the cycling pressure switch in order
to turn off the heat source before the boiler pressure reaches its limit and automatically
resets after the pressure drops below the lower limit set point.
Blowdown/Drain
Solenoid Valve .......
This valve is plumbed into the drain line of the boiler. Newer steamer models will
automatically blowdown when power is turned off by using a normally open solenoid
valve. Older models can have a solenoid valve that is activated by depressing a separate
blowdown timer button, or have a manual “ball” type valve.
Inlet Water Strainer ... A strainer is used in the water inlet line to prevent foreign matter from becoming lodged
in the fill or cold water condenser solenoid valves, and to keep unwanted particles out of
the system. A "Y" strainer should be inserted upstream of the fill solenoid valve. On
models using a direct steam supply, a strainer is also used in the pressure regulating
valve.
Power Switch ......... When turned ON, power is supplied to the controls and the steam generating process is
started in the boiler. The power switch is located on the front of the boiler control box.
Water Inlet Valve ..... The water inlet valve is used to stop water flow to the steamer when the steamer is being
serviced. Newer models will have a small Petcock type valve while older models will be
a “ball” type valve. This valve should remain open during normal operation.
High Limit
Thermostat ...........
A protective device that shuts off the heat source if the boiler temperature exceeds a
specified limit. All standard models are equipped with a surface high limit.
Descaler .............. Hangs submerged in water inside the boiler and is used to help control boiler surface
scaling. Two descalers are used in each boiler.
Handhole Cover
Assembly .............
When unbolted and removed, allows internal examination and cleaning of boiler shell and
its components if required.
Boiler Pressure
Gauge ................
Indicates the amount of steam pressure in the boiler.
Check Valve .......... On models with the delime piping assembly option, prevents the ejection of hot water and
steam out of the delime funnel if the manual delime fill valve were to be opened.
Delime Port
Assembly .............
On models with the delime piping assembly option, allows the boiler and other internal
components to be delimed, easily removing calcium, lime and rust build up.
Gas Pilot .............. Should always remain lit to light the main burners upon a call for heat unless the steamer
will not be in use for an extended period. If the pilot flame goes out, wait 5 minutes before
relighting.
Gas Burners .......... Heats the water in the boiler to generate steam.
Gas Combination
Control Valve .........
A gas solenoid valve that opens to allow gas flow when a call for heat is made. Also
regulates the manifold gas pressure and supplies the gas pilot.
Transformer .......... Provides 24VAC power to ignition control module. (Gas models with electronic ignition.)
Ignition Control
Module ...............
Controls and monitors gas heating. Energizes pilot valve coil to supply gas to pilot,
generates spark to ignite gas at the pilot, monitors the presence of flame and energizes
VL BOILER BASE SERIES CONVECTION STEAMERS - GENERAL
F24650 Rev. A (1017) Page 12 of 93

main valve coil upon a call for heat to supply gas to the main burners. The pilot and main
solenoids are part of the gas combination control valve. (Gas models with electronic
ignition.)
Ignition Control
Module Reset (ON/
OFF) Switch ..........
Controls power to the ignition control module and allows a reset of the module if the gas
ignition exceeds trial time. (Gas models with electronic ignition.)
Heater Contactor
(Electric Boilers) ......
When coil is energized, supplies power to the electric heating elements.
Heating Elements
(Electric Boilers) ......
Heats the water in the boiler to generate steam.
Steam Header
Assembly .............
Main steam supply line from the boiler to the steam header inlet in the cooking control
compartment.
Pressure Relief
Valve .................
A mechanical device that opens to relieve steam pressure in the boiler if the pressure
exceeds 15 psi.
Compartment
Pressure Regulating
Valve .................
Reduces steam pressure form the boiler or building steam (direct and regenerated
models) to supply the compartments a steam pressure of 6 psi. Standard on PS, option
on MS, SS and AS compartment controls.
COOKING COMPARTMENT CONTROLS
The top half of the steamer consists of two to three separate cooking compartments depending on the model. Each
compartment functions independently with its own set of controls. Power is supplied to the controls through the
compartment power switch and the cooking timer control micro switch contacts. Prevent and Automatic models
have a load compensating thermal switch that prevents the controls from receiving power until the compartment
reaches 180°F to close the switch.
Compartment Power
Switch ................
Supplies power to the cooking compartment controls.
Cooking Light
(Red) ..................
When lit, indicates steamer is in a cooking cycle. (All models except manual.)
Cooking Timer ........ Use to set desired cooking cycle time between 0-60 minutes. Energizes the buzzer when
time expires (all models except manual). On Prevent models, also de-energizes the
steam exhaust solenoid valve one minute before the end of a cook cycle to allow
compartment venting.
Buzzer ................ Signals end of a cook cycle; must be turned off manually. (All models except manual.)
Steam Exhaust
Solenoid Valve .......
A normally open valve that allows full compartment venting of air and condensate up to
180°F during compartment heat up and “limited free venting” after energized by the
closing of the thermal switch. The valve remains closed to allow compartment
pressurization to 6 psi until one minute before the end of a cook cycle at which point the
timer control micro switch contacts (SW2) change state and de-energize the valve to vent
the compartment of pressure and steam. (Prevent models.)
Steam Header Inlet
(manifold) .............
Main steam supply line from the boiler for each cooking compartment. Supplies steam to
the manual steam gate valves.
Compartment
Pressure Gauge ......
Indicates the amount of steam pressure in cooking compartments.
VL BOILER BASE SERIES CONVECTION STEAMERS - GENERAL
Page 13 of 93 F24650 Rev. A (1017)

Steam Control Arm
Solenoid ..............
When energized, engages the lift arm (plunger) to raise the steam control arm off of the
catch, allowing it to return to its rear position. This closes the steam inlet gate valve and
opens the steam exhaust gate valve. (Prevent, automatic and standard models.)
Thermal Switch (Load
Compensator) ........
Controls power to the preheat cycle components. Turns the cooking light on, energizes
the steam exhaust solenoid valve and energizes the cooking timer motor to start timing,
after the compartment reaches 180°F. (Prevent and automatic models.)
Steam Gate Valves ... Manual valves actuated by the steam control arm. Allows steam to flow into the cooking
compartment through the inlet steam gate valve when the arm is in a forward position
and exhaust the steam through the exhaust steam gate valve when the arm is at the rear.
Prevent models use a steam exhaust solenoid valve to exhaust the steam and a single
steam gate valve as the steam inlet. The automatic, standard and manual models use
one steam gate valve to exhaust the steam and one additional steam gate valve as the
steam inlet.
Steam Trap
(Condenser) ..........
Exhausts air and condensate from compartment during preheat until the compartment
temperature reaches approximately 180°F. The bellows then close, stopping the exhaust.
(All models except prevent.)
VL BOILER BASE SERIES CONVECTION STEAMERS - GENERAL
F24650 Rev. A (1017) Page 14 of 93

REMOVAL AND REPLACEMENT OF PARTS
COMPONENT LOCATIONS
Fig. 4
VL BOILER BASE SERIES CONVECTION STEAMERS - REMOVAL AND REPLACEMENT OF PARTS
Page 15 of 93 F24650 Rev. A (1017)

Fig. 5
VL BOILER BASE SERIES CONVECTION STEAMERS - REMOVAL AND REPLACEMENT OF PARTS
F24650 Rev. A (1017) Page 16 of 93

Fig. 6
COOKING COMPARTMENT CONTROLS - COMPONENT CONFIGURATIONS
1. Prevent (shown above) Thermal switch, inlet steam gate valve, steam exhaust solenoid valve, steam control
arm solenoid, timer, buzzer and power switch with light. Does not use a steam trap.
2. Automatic Same as prevent except does not include steam exhaust solenoid valve but does include
an exhaust steam gate valve and two steam traps.
3. Standard Same as automatic except does not include thermal switch.
4. Manual Manual and exhaust steam gate valves and a manual timer. Includes two steam traps.
WATER LEVEL CONTROLS - LOW
LEVEL CUT OFF AND
DIFFERENTIAL
DISCONNECT THE ELECTRICAL
POWER TO THE MACHINE AT THE
MAIN CIRCUIT BOX. PLACE A TAG
ON THE CIRCUIT BOX INDICATING
THE CIRCUIT IS BEING SERVICED
Solid State
1. Open the cabinet base doors.
2. Remove the two screws at the top of the boiler
control box and allow cover to drop down.
3. Water level control is mounted on the back side
of cover.
4. Disconnect lead wires from the board and
remove the water level control.
5. Reverse procedure to install and check for proper
operation.
Electro Mechanical
1. Open the cabinet base doors.
2. Remove the two screws from the left and right
side of the water level control box and lift cover
off.
3. Disconnect lead wires from the control being
replaced and remove.
4. Reverse procedure to install and check for proper
operation.
WATER LEVEL GAUGE ASSEMBLY
DISCONNECT THE ELECTRICAL
POWER TO THE MACHINE AT THE
MAIN CIRCUIT BOX. PLACE A TAG
ON THE CIRCUIT BOX INDICATING
THE CIRCUIT IS BEING SERVICED.
1. Open the cabinet base doors and remove the
right side panel.
2. Close the valve at the top and at the bottom of
the gauge assembly.
3. Unscrew the packing nuts at the top and bottom
of the glass tube.
VL BOILER BASE SERIES CONVECTION STEAMERS - REMOVAL AND REPLACEMENT OF PARTS
Page 17 of 93 F24650 Rev. A (1017)

4. Slide the glass tube upwards until the bottom of
the tube is clear of the fitting and lift it out.
5. When reinstalling the tube use new sealing
washers. Do not overtighten the packing nuts; it
could break the gauge glass.
6. Open the top and bottom valves and check for
proper operation.
CYCLING AND HIGH LIMIT
PRESSURE SWITCHES (GAS AND
ELECTRIC MODELS)
DISCONNECT THE ELECTRICAL
POWER TO THE MACHINE AT THE
MAIN CIRCUIT BOX. PLACE A TAG
ON THE CIRCUIT BOX INDICATING
THE CIRCUIT IS BEING SERVICED.
1. Open the cabinet base doors and remove the left
side panel.
2. Remove the two screws at the top of the boiler
control box and allow cover to drop down.
3. The pressure switches are located at the rear of
the box. The pressure switch on the right is the
cycling or primary control; the one on the left is
the high limit control. They are identical switches,
differing only in their settings.
4. Remove the cover from the pressure switch
being replaced and disconnect the lead wires.
5. Disconnect the pressure fittings at the bottom of
the switch.
6. Remove the mounting screws on the back side
of the control box and lift out the pressure switch.
7. Preset the new pressure switch to the
approximate cut-out (off) and cut-in (on) set
points before installing. See the boiler pressure
chart under CYCLING AND HIGH LIMIT
PRESSURE SWITCHES (GAS AND ELECTRIC
MODELS).
8. Reverse procedure to install.
9. Adjust the pressure switch(es) final set points as
outlined under CYCLING AND HIGH LIMIT
PRESSURE SWITCHES (GAS AND ELECTRIC
MODELS) in and check for proper operation.
BOILER ASSEMBLY
DISCONNECT THE ELECTRICAL
POWER TO THE MACHINE AT THE
MAIN CIRCUIT BOX. PLACE A TAG
ON THE CIRCUIT BOX INDICATING
THE CIRCUIT IS BEING SERVICED.
SHUT OFF THE GAS BEFORE SERVICING THE
UNIT.
ALL GAS JOINTS DISTURBED DURING
SERVICING MUST BE CHECKED FOR LEAKS.
CHECK WITH A SOAP AND WATER SOLUTION
(BUBBLES). DO NOT USE AN OPEN FLAME.
1. Blow down the boiler and allow to cool, if
necessary.
2. Ensure that all utilities to the steamer are off and
disconnected. Drain any excess water from the
boiler.
3. Disconnect the steam supply line, power leads
and drain lines from the cooking compartment
top to the boiler base.
4. Disconnect all plumbing connections and power
leads from the components inside the control
boxes that would obstruct the removal of the
boiler through the front of the base, then remove
those control boxes.
5. Disconnect the remaining plumbing and
electrical connections from the boiler to the
controls.
6. Remove the screws holding the flue and flue
collector to the base.
7. Remove the anchor screws holding the boiler to
the frame. Slide the boiler forward. The burner
box, anchored only by the boiler, must be
prevented from sliding forward with the boiler.
8. Reverse procedure to install a new boiler and
check for leaks and proper operation.
VL BOILER BASE SERIES CONVECTION STEAMERS - REMOVAL AND REPLACEMENT OF PARTS
F24650 Rev. A (1017) Page 18 of 93

HIGH LIMIT THERMOSTAT
DISCONNECT THE ELECTRICAL
POWER TO THE MACHINE AT THE
MAIN CIRCUIT BOX. PLACE A TAG
ON THE CIRCUIT BOX INDICATING
THE CIRCUIT IS BEING SERVICED.
1. Open the cabinet base doors.
2. Electric models only - for gas models proceed to
step 3.
A. Newer Models - Not equipped with a high
limit thermostat but rely on the high limit
pressure switch instead.
B. Older Models - The high limit thermostat is
located behind the contactor box cover. On
electric boilers with two heating elements,
the thermostat is connected to one of the
heating element lugs. On electric boilers
with four heating elements, the thermostat
is located on an aluminum plate between
the center pair of elements at the top of the
elements. Remove the thermostat lead
wires and mounting nuts, replace
thermostat and check for proper operation.
3. Gas Models only.
A. Remove the thermostat cover which is
located on the front of the boiler. Disconnect
the thermostat lead wires and remove the
nuts securing the high limit thermostat to the
boiler surface.
4. Reverse procedure to install and check for proper
operation.
BOILER FILL AND COLD WATER
CONDENSER SOLENOID VALVES
DISCONNECT THE ELECTRICAL
POWER TO THE MACHINE AT THE
MAIN CIRCUIT BOX. PLACE A TAG
ON THE CIRCUIT BOX INDICATING
THE CIRCUIT IS BEING SERVICED.
1. Turn off the water supply to the steamer.
2. Open the cabinet base doors and remove the two
screws at the top of the boiler control box and
allow cover to drop down. Both solenoid valves
are located side by side near the front of the boiler
control box with the boiler fill on the right and the
cold water condenser to the left.
3. Disconnect the power lead wires from the
solenoid valve being serviced.
4. Disconnect the water lines for the valve being
serviced and remove the valve.
5. Reverse procedure to install.
PILOT AND THERMOCOUPLE
ASSEMBLY (GAS MODELS)
DISCONNECT THE ELECTRICAL
POWER TO THE MACHINE AT THE
MAIN CIRCUIT BOX. PLACE A TAG
ON THE CIRCUIT BOX INDICATING
THE CIRCUIT IS BEING SERVICED.
SHUT OFF THE GAS BEFORE SERVICING THE
UNIT.
ALL GAS JOINTS DISTURBED DURING
SERVICING MUST BE CHECKED FOR LEAKS.
CHECK WITH A SOAP AND WATER SOLUTION
(BUBBLES). DO NOT USE AN OPEN FLAME.
1. Open the cabinet doors to access the pilot and
thermocouple assembly. The assembly is
located to the right of the center burner and half
way back from the front.
2. Disconnect thermocouple and pilot gas supply
tubing from the combination control valve.
3. Remove the two screws holding the pilot to its
bracket.
4. Replace the thermocouple or pilot assembly and
check for proper operation.
VL BOILER BASE SERIES CONVECTION STEAMERS - REMOVAL AND REPLACEMENT OF PARTS
Page 19 of 93 F24650 Rev. A (1017)

GAS COMBINATION CONTROL
VALVE
DISCONNECT THE ELECTRICAL
POWER TO THE MACHINE AT THE
MAIN CIRCUIT BOX. PLACE A TAG
ON THE CIRCUIT BOX INDICATING
THE CIRCUIT IS BEING SERVICED.
SHUT OFF THE GAS SUPPLY BEFORE
SERVICING THE UNIT.
ALL GAS JOINTS DISTURBED DURING
SERVICING MUST BE CHECKED FOR LEAKS.
CHECK WITH A SOAP AND WATER SOLUTION
(BUBBLES). DO NOT USE AN OPEN FLAME.
NOTE: Gas combination control valves are not
serviceable and should not be disassembled. Once
the problem has been isolated to this control, replace
it. Do not attempt to repair the assembly.
1. Open the cabinet base doors and remove the two
screws at the top of the boiler control box and
allow cover to drop down.
2. Disconnect electrical supply wires and conduit
running to the combination control valve.
3. Disconnect the thermocouple lead (if applicable),
pilot gas supply tube from control and pipe
connections on each side of the control.
4. Reverse procedure to install.
5. Set manifold pressure as outlined under GAS
MANIFOLD PRESSURE ADJUSTMENT .
6. Check for proper operation.
COMPARTMENT GASKET AND
DOOR SCREW NUT, DOOR AND
BUSHINGS
Gasket
1. Open the compartment door to be replaced.
2. Remove screws securing the gasket retaining
plate to the gasket.
Fig. 7
3. Lift the gasket off the inner door plate.
4. Position the new gasket on the inner door plate
and reverse procedure to install.
NOTE: Damage to the gasket sealing surface, such
as nicks or cuts, will cause steam leakage.
Door Screw Nut
1. Open compartment door to be serviced.
2. Turn screw handle fully clockwise to extend inner
door plate assembly.
3. Lift the inner door plate assembly up, until the
mounting pins are out of the holes in the pressure
bar and set the assembly aside.
Fig. 8
VL BOILER BASE SERIES CONVECTION STEAMERS - REMOVAL AND REPLACEMENT OF PARTS
F24650 Rev. A (1017) Page 20 of 93