Vulcan-Hart MHB24G, VHX24G5, VHX24G User Manual
SERVICE MANUAL
VHX BOILER BASE SERIES
HIGH EFFI CIENCY GAS
STEAMERS
VHX24G ML-114795
VHX24G5 ML-126590
MHB24G ML-114954 (BASE ONLY)
VHX24G SHOWN
This Manual is prepared for th e use of trained Vulcan Service
Technicians and should not be used by those not properly
qu alif ied. If yo u have attend ed a Vulcan Service School for this
product, you may be qualified to perform all the procedures
described in this man ual.
Thi s manu al i s no t i nten ded to be al l en comp assi ng . I f you have
not attende d a Vulcan S ervic e School for this produ ct , 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 th e n ecessary too ls, in strument s and skills should be
performed b y a trained Vu lcan Service Technician .
Reproduction or other use of this Manual, without the express
written consent of Vulcan, is prohibited.
- NOTICE -
A product of VULCAN-HART LOUISVILLE , KY 40201-0696
F24700 (October 2001)
VHX SERIES STEAMERS
TABLE OF CONTENTS
GENERAL............................................................................. 4
Installation......................................................................... 4
Maintenance ....................................................................... 4
Cleaning .......................................................................... 4
Introduction ........................................................................ 4
Steam Cooking.................................................................. 4
Compartment Pan Capacity ........................................................ 4
Model Designations .............................................................. 4
Boiler Code Descr iptions .......................................................... 4
Boiler Control Styles.............................................................. 5
Water Conditi oning .................................................................. 6
Specifications ...................................................................... 6
Water Supply ................................................................... 6
Electrical ...................................................................... 6
Boiler Pressure.................................................................. 6
Gas Supply ..................................................................... 7
Tools ............................................................................. 7
STEAMER OPERATION.................................................................. 8
Cabinet Base Boiler .................................................................. 8
Cooking Compartment Controls......................................................... 8
Boiler Blowdown and Steamer Shut off ................................................... 9
Component Func tion ................................................................ 10
Cabinet Base Boiler Controls ...................................................... 10
Cooking Compartment Controls .................................................... 12
REMOVAL AND REPLACEMENT OF PARTS ................................................ 13
Component Locat ions ............................................................... 13
Cabinet Base Boiler Controls ...................................................... 13
Cooking Compartment Controls .................................................... 15
Water Level Controls
(Main or Auxiliary LLCO) ......................................................... 15
Relay Board....................................................................... 15
Water Level Gauge Assembly ......................................................... 16
Pressure Switches .................................................................. 16
Boiler Assembly.................................................................... 16
Boiler Fill and Cold Water Condenser Solenoi d V alves ...................................... 17
Pilot Gas Valve .................................................................... 17
Main Gas Valve.................................................................... 17
Burner Head Assembly .............................................................. 18
Complete Burner Assembly ........................................................... 18
Heat Exchanger .................................................................... 19
Cooking Compartment Door(s)......................................................... 21
SERVICE PROCEDURES AND ADJUSTMENTS .............................................. 23
Boiler............................................................................ 23
Inspection..................................................................... 23
Clean-Out ..................................................................... 23
Deliming...................................................................... 23
Descaler (Cathodic Protector ) ...................................................... 24
Water Level Probe Housing Blowdown .................................................. 24
Water Level Controls Test ............................................................ 25
Pressure Switches .................................................................. 27
Fill and Cold W ater Solenoid V alves .................................................... 28
Boiler Blowdown/drain Solenoid Valve .................................................. 29
Inline Water S trainer Cleaning ......................................................... 29
Main Burner Ignition Checks .......................................................... 30
F24700 (October 2001) Page 2 of 68
VHX SERIES STEAMERS
Air Pressure Switch Adjustment........................................................ 33
Gas Pilot Pressure Adjustment......................................................... 34
Gas Manifold Pressure Adjustment ..................................................... 36
Ignition Control Module Checks ........................................................ 37
Cooking Compartment............................................................... 39
Intake Shut-Off Valve Adjustment (Steam Flow)........................................ 39
Door Sealing Adjustment ......................................................... 39
Door Latch Adjustment........................................................... 40
ELECTRICAL OPERATION .............................................................. 41
Water Level Controls................................................................ 41
Low Level Cut-Off & Differential Control.............................................. 41
Auxiliary Low Level Cut-Off ....................................................... 42
Relay Board....................................................................... 43
Board Layout and LED Legend ..................................................... 43
Boiler Operational Status (LED Indicator) ............................................. 44
Sequence of O per ation .............................................................. 46
New Style Controls - Boiler........................................................ 46
Old Style Controls - Boiler ........................................................ 48
Cooking Compartment Controls .................................................... 50
Schematics ....................................................................... 52
Models Built After 5/25/00 (New Style Boiler Controls) ................................... 52
Models Built Befor e 5/25/00 (Old S tyle Boiler Controls) .................................. 54
Cooking Compartment Controls .................................................... 55
Wiring Diagrams ................................................................... 56
Models Built After 5/25/00 (New Style Boiler Controls) ................................... 56
Models Built Befor e 5/25/00 (Old S tyle Boiler Controls) .................................. 58
Cooking Compartment Controls .................................................... 60
TROUBLESHOOTING .................................................................. 61
CONDENSED SPARE PARTS LIST ........................................................ 68
© VULCAN 2001
F24700 (October 2001)Page 3 of 68
VHX SERIES STEAMERS - GENERAL
GENERAL
INSTALLATION
Refer to the Installation and Operation Manual for
detailed installation instructions.
MAINTENANCE
Refer to the Installation and Operation Manual for
specific maintenance instruct ions.
CLEANING
Refer to the Installation and Operation Manual for
specific cleani ng instructions.
INTRODUCTION
Steam Cooking
Convection cooking in pressure-less steaming
compartments will steam cook fresh foods or will
steam def rost and cook froz en foods prov iding the
maximum c olor, flav or and nutritional value with the
least expenditure of energy and labor. T he pr essureless steaming compartm ents on the VHX series
allows the operator to open and close the door,
anytim e during a cooking cycle. T he steam supply
will shut off when the door is opened, then re-start
when the door is closed.
Compartment P an Capacity
PAN
DEPTH
(INCHES)
MODEL
VHX24G
NUMBER OF PANS
PER COMPARTMENT
24.0
32.5
Model Desi gnations
Boiler Code Descriptio ns
Vulcan-Hart incorporates redundant c ontrols in
compliance with the CSD-1 controls and safet y
devices for boiler construction on these High
Efficienc y S team models. A Description of the c ode
is listed below.
CSD-1 Constructi on
electrical safety circuits that, i f tri pped, must
manually be reset after the condit ion causing the trip
subsides. These controls consist of - (1) dual
function water level cycling and low level cut off
control and ( 1) si ngle funct ion low water level cut-off
control ( A ux LLCO) and a high pr essure rel ief switch
in conjunction with a mechanical pr essure rel ief
valve. A dditional ly, both circuits have indi vidual
indicat or lights for low water and high pressure that
will illuminate for a visual verification of the
shutdown mode.
CSD-1 construction requires operator intervention i n
the ev ent of a shutdown. The i ndicator l ights show
the operator which safety system was shutdown.
- Redundant controls in the
61.0
34.0
VHX24G5
Pan Size 12" x 20"
F24700 (October 2001) Page 4 of 68
52.5
10 1.0
VHX SERIES STEAMERS - GENERAL
Boiler Control Styles
VHX Steamers manufactur ed usi ng the old style boiler controls ended on 5/19/00. Steamers that were in stock at
the time of the boiler contr ol changeov er were removed and equipped with the new style c ontrols without
recording t he serial number for track ing.
Refer to the pictures bel ow to differentiate between the old style and new style boiler controls.
F24700 (October 2001)Page 5 of 68
VHX SERIES STEAMERS - GENERAL
WATER CONDITIONING
Furnishing the boiler wit h treated water to reduce
scale formation is import ant. Scale format ion will
reduce steam out put, cause prematur e c omponent
failure, and shorten equi pment life. Most water
supplies contai n scale producing m inerals such as
Calcium and Magnesium. As steam is generated,
the mi nerals remai n and dissolve into the water. As
the concentrat ion of these minerals i nc r eases past a
certain point, they pr ec ipitate from the water and
coat the inside of the boi ler, heating element s, and
water level sensors. Because of the high
temperat ure of these surf ac es, the precipitated
minerals bake onto them and bec ome v er y difficult
to remove.
This may c ause several probl ems:
1. Reduced heat transf er eff iciency.
2. Premature heating element failures.
3. False readings from water l evel sensors.
These problem s are common to any manufacturer's
steamer regardless of design, but t hey c an all be
minimized by furnishing the boiler with treated
water.
Other factors affecting steam generati on ar e iron
content, amount of c hlorination and dissolved
gases.
SPECIFICATIONS
Water Supply
The fact that a water supply is potable is no
guarantee that it is suitable for steam generation.
The supply connect ion to the steam gener ator
should be “treated” water and must be within t he
guideli nes listed below. For dr ain water cooling only,
an “untreated“ water suppl y c onnec tion should be
used.
Supply pressure should be 20-60 psig
In line strainer f or suppl y 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 fact or 7 to 8
(*17.1 ppm = 1 grain of har dness)
Electrical
Voltage - 120/ 60/1
Amps - 3.0 (max)
The desired water propert ies can best be achieved
by using a
system.
The water level probes in the boiler use ions i n the
water to detect the water level.
demineralized or de-ionized water since it is
"non conductive" and the water level can not be
detected.
The use of strainers or
remove mi nerals from the water.
Water supplies vary fr om state to state and from
locati ons wit hin a state. Therefore, a
treatment specialist should be consulted
the installation of any steam generating equipment.
Steamers that operate over a long peri od of time
without the benefit of a water treatment system,
which have developed a heavy scale build up,
should be cleaned before using the system.
properly maintained water treatment
Do not use fully
non approved
filters will not
water
before
Boiler Pressu re
Operating - 8 to 10 psi
Maximum - 15 psi
F24700 (October 2001) Page 6 of 68
Gas Supply
VHX SERIES STEAMERS - GENERAL
MODEL
VHX24G
VHX24G5
MHB24G
NOTE
Standard
INPUT
(BTU/HR)
NAT. PROP. NAT. PROP. NAT. PROP.
200,000 200,000 3.0 3.0 3.5 3.5 7.0 11.0
270,000 270,000 3.0 3.0 3.5 3.5 7.0 11.0
200,000 200,000 3.0 3.0 3.5 3.5 7.0 11.0
270,000 270,000 3.0 3.0 3.5 3.5 7.0 11.0
200,000 200,000 3.0 3.0 3.5 3.5 7.0 11.0
270,000 270,000 3.0 3.0 3.5 3.5 7.0 11.0
1. Output Boiler Horsepower (BHP): 4.3 BHP for 200,000 BTU; 5.5 BHP for 270,000 BTU.
:
2. Input BTU/HR difference is based on gas orifice size and air orifi c e size.
MANIFOLD
PRESSURE
(INCHES W.C. )
PILOT
PRESSURE
(INCHES W.C. )
NATURAL PROPANE
MINIMUM
RECOMMENDED
LINE PRESSURE
(INCHES W.C. )
RECOMMENDED
TOOLS
MINIMUM
MAXIMUM
ALLOWED
14.0
Standard set of hand tools.
Volt-Ohm-Meter (VOM) with AC current tester.
(Any quality VOM wit h a sensit ivity of at least 20,000 ohm s per volt c an be used)
Gas leak checking equipment.
Gas pressure manomet er
Temperat ure meter and t her mocouple.
Special
The recommended deli ming chemical for the water treatment system in use, for deliming of the boiler.
Contact Vul c an A uthorized Service Centers.
Heat Exchanger Gasket (joi nt sealant strip, Teflon) P /N 854058-1.
F24700 (October 2001)Page 7 of 68
VHX SERIES STEAMERS - OPERATION
STEAMER OPERATION
CABINET BASE BOILER
Ensure that all utility connections to the steamer
have been made and are turned ON and t hat the
knob on the main gas valve is i n the ON positi on.
The VHX Series steam er s are CSD- 1 c ompliant and
are equipped with amber colored lights on the boiler
control panel for Hi gh P ressure and Low Water level
that illuminate and stay on until the boiler is full and
the manual reset switch pressed.
1. Turn power switch ON.
A. Amber colored lights on the boiler control
panel for High Pressure and Low Water
level will illuminate. and stay on until t he
boiler is full and the reset switch is
pressed.
B. Water will begin filling the boiler and the
blowdown solenoid v alve will close. The
boiler shoul d fill, in four to eleven minutes.
C. As water fills the boiler, observe water
level gauge glass to verify that water i s i n
boiler. See "WATER LEVEL GAUGE
ASSEMBLY" in "COMPONENT
FUNCTION” and COMPONENT
LOCATION “ under "REMOVAL AND
REPLACEMENT OF PARTS".
D. Onc e the water in the boiler reaches the
minimum level, the green ready light on
the boiler control panel will illuminate.
NOTE: If the fill has stopped, one visible inc h
of water should be in the gauge glass.
2. Press the reset switch on the boiler control
panel.
A. Low water level safety circuit will be reset
and the Low Wat er lev el light (amber) will
turn off.
B. High pressure safety circuit will be reset
and the High Pressure light (amber ) will
turn off.
C. Sparking will begin three seconds later to
light the pilot bur ner.
1) I f the pilot burner lights, a signal is
sent back through the igniti on c able
indicat ing the presence of pilot burner
flame and sparking stops.
2) I f pil ot burner flame is not
established immedi ately, sparki ng will
continue for 90 seconds. After that
duration, the ignition control module
will lock out and needs to be reset to
start the pilot and main burner li ghting
cycle again.
New Style Controls
Pilot gas valve operates on a "timer"
circuit allowing gas flow to the pilot
for approximately 15 seconds, during
ignition trial, then turns off.
D. Main gas valve opens, burner ignites and
begins to heat the water in the boil er . After
approximately 15 minutes, steam should
be present for c ook ing product. O bserve
that the boi ler pressure gauge indicates a
steam pressure of 8- 10 psi before the
burner shuts OFF.
3. The cycling pressure switch will maintain steam
pressure in the boiler by cycling the main
burner ON and OF F.
- Power to the
COOKING COMPARTMENT
CONTROLS
When the steam pressure in the c ook ing
compartment manifol d reaches approximately 3 psi,
the cooking compartment pressure switch closes,
suppling power to the ot her c ook ing compart ment
controls. The ready lights will illuminate and after
approximately one minute, the steam pressure in
the boiler will reach the upper limit of 10 psi. If the
pressure drops below approximately 3 psi, the
pressure switch will open, removing power fr om the
controls.
NOTE:
immediatel y after t he ready light c omes on, steam
solenoid chattering will be heard (oil canning) and
the ready lights will flash for several seconds. This
conditi on is caused by the mani fold steam pressure
being on the “fringe” of the pressure switch set point.
When a c ook timer is set, the compar tment steam
solenoid valve opens causing the manifold st eam
pressure to drop, slightly below the pressure switch
set point. At the same time, steam pressure is still
increasing in the boiler . This opposing condition
causes a pressure “bounce” to occur. After the
steam pressure passes approxim ately 4 psi this
conditi on subsides. Dur ing normal oper ation, this
conditi on will not be seen.
On initial startup, if a cooking ti mer is set
F24700 (October 2001) Page 8 of 68
VHX SERIES STEAMERS - OPERATION
1. With both timer knobs at the off posi tion, open
the compartment doors and observe that no
steam has entered the c ook ing compart ments,
then close the doors.
2. Set both timer knobs at 2 minutes. The r eady
lights will go off, the cooking lights will come
on, and steam will begin to enter the
compartments.
3. After one minute, open eac h door and observe
that steam has ceased to enter each
compartment, cooking lights go back to ready,
and one minut e is remaining on each cook
timer.
4. Close doors and steam generation and cook
timing will resume. Observe the floor drain to
ensure that live steam from compart ments is
being cooled by cold water fr om the cold water
condenser solenoid valve.
5. When timer k nobs reac h " 0" , buzzers will
sound, steam generation will cease, cooking
lights will go off and ready lights will come on.
To silence buz z er s, turn timer knobs to off
position.
BOILER BLOWDOWN AND
STEAMER SHUT OF F
Turn the steamer off at least once daily to bl owdown
the boiler. This will aid in the removal of sediment
and scale buil d- up in the boil er .
NOTE
: Boil er should be with-in normal operating
pressures.
1. Turn power switch OFF .
2. Boiler blowdown sequence starts.
A. The blowdown/drain solenoid valve will be
de-energized and t he boiler will begin to
drain.
B. The cold water condenser solenoid will
operate, as needed, to condense steam
and to cool the water going into the dr ain.
6. During idle t ime or a cooking cycle, the heating
system will cycle on and off as necessary to
maint ain steam pressure in t he boiler.
7. Turn power switch off to remove power from
the steamer.
A. Boiler blowdown starts.
F24700 (October 2001)Page 9 of 68
VHX SERIES STE A M E RS - COMPONENT FUNCTION
COMPONENT FUNCTION
CABINET BASE BOILER CONTROLS
Power Switch (ON/OFF)
Reset Switch (Manual)
Boiler Fill Solenoid Valve
Cold Water Condenser
Solenoid Valve
Blowdown/Drain
Solenoid Valve
Cycling P ressure Switch
High Limit Pressure Sw itch
................. Allows cold water flow into the boiler blowdown drain box to condense
................. A normally open valve (N.O.) that closes to allow boiler to fill and
......... When turned ON, supplies power to the control cir c uit.
.......... Resets the low water level safety circuit on initial startup or the
......... Controls boiler pressure between prescribed limits by turning the heat
occurrence of a low water condition and allows the boil er to fill with
water. Also, resets the high pressure lev el safety circuit on initial startup
or the occurrenc e of a high pressure condition and all ows the gas
ignition cycle to start.
........ Admits water to the boiler when dem anded by the water level control to
maintain the correct water level in the boiler.
steam and cool the hot water befor e its discharge int o the drain.
pressurize when power switch is turned ON and opens when power
switch is turned off to blowdown and drain the boiler. This valve is
plumbed into the drain line of the boiler.
source on and off.
...... Protects the boiler from pressures above 15 psi by removing power from
the heating ci rcuit. Thi s pressure setting is higher than the cycling
pressure switch in order to t ur n off the heat source before the boiler
pressure reaches its limit. A fter the pr essure drops below approximat ely
12psi, press the rest switch of the front control panel to rest the safety
circuit.
Main Water Level Control
Auxiliary Water Level Control
Transformer
Ignition Control Module
Main Gas Valve
Pilot Gas Valve
................... Provides 24VAC power to ignition control modul e and heating circ uit.
................ A gas solenoid valve that opens to allow gas flow to the main burner
................ A gas solenoid valve that opens to allow gas flow to the pilot to ignite the
........ A dual functioning control that allows water to fill and maintain the
......... Controls and m onitors gas heating. E ner gizes pilot valve coi l to supply
proper level in the boiler pr oviding dif ferenti al water level control; and
shuts off the main gas valve if the water level drops too low providing
low level cut-off protection. The water level control works by using three
different probe lengths to moni tor the water level. The probes consist of
a high level (HL) , low level (LL) and low water cut- off ( LLCO).
..... A back up to the low level cut-off on the main control. Protects the boiler
and heating system c omponents from a low water cut-off condition by
opening the 24VAC volt age path to the heati ng system circuit. Al so,
energizes the l ow water "l ight" on the front contr ol panel.
gas to pilot, generates spark to ignite gas at the pilot, monitors the
presence of flame and energizes the main and pilot valve coi ls on the
main gas valve upon a call for heat.
after the successful ignition of the pil ot burner when a call for heat is
made.
main burner when a call f or heat is made. T he valve is energized by a
tim e delay circ uit on the rel ay boar d dur ing ignit ion trial for
approximately 15 seconds. New styl e c ontrols only.
Combustion Blower
F24700 (October 2001) Page 10 of 68
............ Provides forced air to the gas/air mixture for gas pilot and m ain burner
combustion.
VHX SERIES STE A M E RS - COMPONENT FUNCTION
Relay Board
................... Provides a centralized location for wire harness connections and power
transfer through board relays (K1-K 7) to the steamer controls. Also,
provides a condition or component t r oubleshooting indicator by utilizing
seventeen LED’S on the board to represent the status of the condi tion or
component in the operation sequence. For an LED legend, see "RELA Y
BOARD" under "E LE CTRICAL OPERATION". New style c ontrols only.
: The relay’s below are mounted on the relay board and are not
NOTE
K1 Relay
...................... Energized when Aux LLCO is satisfied and turns ready light ( gr een) ON
if high limit pressure switch i s closed. Also, K1 allows K3 to be energized
when the reset switch is pressed.
K2 Relay
...................... Energized when high li mit pressure switch is closed (high limit pressure
conditi on sat isfied). When K 1 & K 2 ar e ener gized, the ready light (green)
will be ON.
K3 Relay
...................... When Aux LLCO is satisfied and the m anual reset switch is activat ed,
K3 is energized. When K 3 is energized, tur ns water error light OFF and
allows the ignition sequence to begi n. K3 must be energi z ed for ignition
sequence to begin.
K4 Relay
...................... Energized when K2 contacts are closed and manual reset switch is
activated. When K4 i s energized, the high pressure light is OFF. When
K3 and K4 are both energized, power to the ignition system is supplied.
K5 Relay
...................... Energized when operating conditions are m et and reset switch is
activated. Pr ovides power to start combustion blower.
individual ly replaceable.
K6 Relay
...................... Energized by time delay circuit for approx imately 15 seconds. When K 6
and K7 are energized, power is supplied to the pilot gas valve.
K7 Relay
...................... Energized when pilot voltage (PV) f r om the ignition module is present.
Also used in the time delay c ircuit.
......................... Ignites to light the main burner upon a call f or heat.
Pilot
Main Burner
................... Heats the water in the boiler to gener ate steam.
Water Level
Gauge Assembly
............... Permits a visual confirmation the water level is being maintained in
boiler dur ing operation. The correct water l evel is approximately one
visible inch in the glass. The manual valves at the top and bott om of this
assembly m ust be full y open and only closed if the glass tube is
damaged.
Water Inlet Valve (manual)
....... The water inlet valve is used to stop water flow to the steamer when the
steamer i s bei ng serviced. This valve should remai n open dur ing normal
operation.
Inline Water Strainer
............ A "Y" strainer is installed upstream of the blowdown solenoid valve to
prevent forei gn matter from becoming lodged in the valve. A strainer
(not supplied) shoul d also be installed in the water supply line to prevent
forei gn matter from becoming l odged in the fill or cold water condenser
solenoid valves and to keep unwanted partic les out of the system.
Pressure Relief V alve
........... A mechani c al device that opens to relieve steam pressure in the boiler if
the pressure exceeds 13 psi.
High Pressu re Relief Valve
Descaler
Boiler Pressu re Gauge
...................... Hangs below the water level inside the boi ler and is used to help cont r ol
.......... Indicates the amount of steam pressure in the boi ler.
Steam Header Assembly
....... A back-up mechanical device that opens to relieve steam pressure in
the boiler if the pressure exceeds 15 psi.
boiler surface scaling. Two descalers are used in each boiler.
......... Main steam supply line fr om the boiler to the steam header inlet in the
cooking control compar tment.
F24700 (October 2001)Page 11 of 68
VHX SERIES STE A M E RS - COMPONENT FUNCTION
COOKING COMPARTMENT CONTROLS
The upper section of the steam er c onsi sts of two separate cooking compartm ents. Each compartment functions
independently wi th its own set of contr ols. Power is supplied to the controls only after the steam pressure rises
above t he c ompartm ent pressure switch setting to close the N.O. contacts.
Ready Light (Green)
Cooking Light (Red)
Cooking Timer
Buzzer
Door Switch
Steam Solenoid Valve
Compartment P r essure Switch
Manifold Pressure Gau ge
Steam Supply Manifold
....................... Signals end of a cook cycle, must be turned off manual ly.
................... Removes electrical power to the timer. If time is dialed on the cooking
............ When lit, indicates steamer is ready to cook.
............ When lit, indicates steamer is in a cooking cycle.
................. Use to set desired cooking cycle time between 0-60 minutes. When a
........... When energi zed, opens to allow steam into the cooking compartment
........ Indicates the amount of steam pressure in manifold. The intak e shut- off
.......... Main steam supply line fr om the boiler for eac h c ook ing compart ment.
tim er is set, the steam suppl y sol enoid valve is energized to al low steam
into the cook ing compartment but only after the boiler has reached its
operating pressure. Also, energizes the buzzer when time expires.
tim er and compartments are steaming, removes power to the steam
solenoid valve when the compart ment door is opened.
(normally closed valve).
.... Supplies power to the controls only after the steam pressure ri ses above
approximately 3 psi to close the compartment pressure switch. The
switch remains closed as long as steam pressure stays above this
pressure.
valve should be adjusted so manifold pressure remains at 9 psi with both
compartments on.
Supplies steam up to the steam sol enoid valve.
Intake Shut-Off Valve
........... Main steam supply shut-off from the boiler t o the steam supply manif old.
This valve should NOT be left fully O P E N to boiler steam supply. See
“INTAKE SHUT-OFF VALVE ADJUSTMENT (STEAM FLOW)" in
“SERVICE PROCEDURES AND ADJUSTMENTS".
F24700 (October 2001) Page 12 of 68
VHX SERIES STEAMERS - REMOVAL AND REPLACEMENT OF PARTS
REMOVAL AND REPLACEMENT OF PARTS
COMPONENT LOCATIONS
Cabinet Base Bo iler Contro ls
F24700 (October 2001)Page 13 of 68
VHX SERIES STEAMERS - REMOVAL AND REPLACEMENT OF PARTS
Cabinet Base Bo iler Contro ls Contin ued
F24700 (October 2001) Page 14 of 68
VHX SERIES STEAMERS - REMOVAL AND REPLACEMENT OF PARTS
Cooking Compartment Controls
WATER LEVEL CONTROLS
(MAIN OR AUXILIARY LLCO)
WARNING:
POWER TO T HE MACHINE AT THE MAIN
CIRCUIT BO X. P LA CE A TAG ON THE CI RCUIT
BOX INDICATING THE CIRCUIT IS BEING
SERVICED.
1. Open the cabinet base door.
2. Remove the cover from the pressure switch
control box to access the water level controls.
Refer to "CABINET BASE BOILER
CONTROLS" under "COMPONENT
LOCATIONS" in "REMOVAL AND
REPLACEMENT OF PARTS".
3. Disconnect l ead wir es from the boar d being
replaced.
4. Compress the lock ing tab on the board
mounti ng "standoffs" and remove the water
level control.
5. Reverse proc edur e to install and c hec k for
proper operati on.
DISCONNECT THE ELECTRICAL
RELAY BOARD
WARNING:
POWER TO T HE MACHINE AT THE MAIN
CIRCUIT BO X. P LA CE A TAG ON THE CI RCUIT
BOX INDICATING THE CIRCUIT IS BEING
SERVICED.
1. Open the cabinet base door.
2. Remove the cover from the main control box to
access the relay board. Refer to "CAB INET
BASE BOILER CONTROLS" under
"COMPONENT LOCATIONS" in "REMOVAL
AND REPLACEMENT OF PARTS".
3. Disconnect all lead wires f r om the board.
4. Compress the lock ing tab on the board
mounti ng "standoffs" and remove the relay
board.
5. Reverse proc edur e to install and c hec k for
proper operati on.
DISCONNECT THE ELECTRICAL
F24700 (October 2001)Page 15 of 68
VHX SERIES STEAMERS - REMOVAL AND REPLACEMENT OF PARTS
WATER LEVEL GAUGE
ASSEMBLY
WARNING:
POWER TO T HE MACHINE AT THE MAIN
CIRCUIT BO X. P LA CE A TAG ON THE CI RCUIT
BOX INDICATING THE CIRCUIT IS BEING
SERVICED.
1. Open the cabinet base door 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 t he top and bottom
of the glass tube.
4. Slide t he glass tube upwards until the bottom of
the tube is clear of the fitt ing and lift it out.
NOTE
damaged or broken.
NOTE:
gauge glass may break.
5. Install the tube using new sealing washers.
6. Open the top and bottom valves.
7. Turn the power switch ON and allow boiler t o
come up to pressure.
8. Check gauge glass for water/steam leaks and i f
necessary, graduall y tighten packing nuts until
leak stops.
DISCONNECT THE ELECTRICAL
: Clean tube if dir ty or clogged and replace if
Do not ov er tighten the pack ing nuts or
PRESSURE SWITCHES
WARNING:
POWER TO T HE MACHINE AT THE MAIN
CIRCUIT BO X. P LA CE A TAG ON THE CI RCUIT
BOX INDICATING THE CIRCUIT IS BEING
SERVICED.
1. Open the cabinet base door and remove the
left side panel.
2. Remove the cover from the pressure switch
control box to access the pressure switches.
Refer to "CABINET BASE BOILER
CONTROLS" under "COMPONENT
LOCATIONS" in "REMOVAL AND
REPLACEMENT OF PARTS".
3. The pressure switches are located at the
bottom of the box . The pressure switch on the
left is the cycling
the right is the high limit
4. If replacing:
A. Cycling control - remove cov er from
DISCONNECT THE ELECTRICAL
or primary control ; the one on
control.
pressure switch and disconnect the lead
wires.
1) Remove the mounti ng screws on the
back side of the control box and lift
out the pressure switch. Proc eed to
step 5.
B. High li mit control - disconnec t the lead
wires.
5. Disconnect the pressure fittings at the bottom
of the switc h.
6. Preset the new pressure switch to the
approximate cut-out (OFF) and cut-in (O N) set
points befor e installing. Refer to "PRESSURE
SW ITCHES" in " S E RV ICE PROCEDURES
AND ADJUSTMENTS".
7. Reverse proc edur e to install .
8. Adjust the pressure switch(s) final set points as
outlined under "P RESSURE SWITCHES" in
"SERVICE PROCEDURES AND
ADJUSTMENTS".
BOILER ASSEMBLY
WARNING:
POWER TO T HE MACHINE AT THE MAIN
CIRCUIT BO X. P LA CE A TAG ON THE CI RCUIT
BOX INDICATING THE CIRCUIT IS BEING
SERVICED.
WARNING:
SERVICING THE UNIT.
WARNING:
DURING SERVI CING MUST BE CHECK E D FOR
LEAKS. CHECK WITH A SOAP AND WATER
SOLUTION (BUBBLES). DO NOT USE AN OPEN
FLAME.
1. Blowdown the boiler and, if nec essary, allow to
cool.
2. Disconnect the steam supply line, power leads
and drain lines from the cooking compartment
top to the boi ler base.
3. Refer to " HE A T EXCHANGER" and perform
steps 3 through 12A.
4. Remove bolts securing the boiler t o frame.
5. Drain any remaining water from t he boiler.
A. The suggested methods are:
DISCONNECT THE ELECTRICAL
SHUT OFF THE GAS BEFORE
ALL GAS JOINTS DISTURBED
1) Where the dr ain line exits the boiler
on the lower left side, separate the
drain line union.
2) Remove the access panel between
the boiler and the cooking
compartment on the right side.
3) Disconnect the steam supply hose
from the cooking compartment steam
manifold.
F24700 (October 2001) Page 16 of 68
VHX SERIES STEAMERS - REMOVAL AND REPLACEMENT OF PARTS
a. From t he bottom right side, raise
the boiler two to three inches so
it tilts to the left. When the
remaining water has drained out,
lower the boiler before.
proceeding.
B. Remove the drain/ scale clean-out plug
from the bottom of the boiler.
6. Slide t he boiler forward and remove it from
base frame.
7. Install a new boi ler and secure it t o frame.
8. Refer to " HE A T EXCHANGER" and perform
steps 13 through 15.
9. Reconnect all steam, water, dr ain and power
connections and check for proper operat ion.
BOILER FILL AND COLD WATER
CONDENSER SOLENOID VALVES
WARNING:
POWER TO T HE MACHINE AT THE MAIN
CIRCUIT BO X. P LA CE A TAG ON THE CI RCUIT
BOX INDICATING THE CIRCUIT IS BEING
SERVICED.
1. Turn off the water supply to the steamer.
2. Open the cabinet base door and remove the
cover from the pressure switch control box to
access the solenoid valves. Both solenoi d
valves are l oc ated side by side at the r ear of
the box with the boiler fill near the bottom and
the cold water condenser near the middle.
Refer to "CABINET BASE BOILER
CONTROLS" under "COMPONENT
LOCATIONS" in “REMOVAL AND
REPLACEMENT OF PARTS”.
3. Disconnect the power l ead wir es from the
solenoid valve being serviced.
4. Disconnect the water lines for the valve bei ng
servi ced and remove the valve.
5. Reverse proc edur e to install .
DISCONNECT THE ELECTRICAL
PILOT G AS VALVE
WARNING:
POWER TO T HE MACHINE AT THE MAIN
CIRCUIT BO X. P LA CE A TAG ON THE CI RCUIT
BOX INDICATING THE CIRCUIT IS BEING
SERVICED.
WARNING:
SERVICING THE UNIT.
DISCONNECT THE ELECTRICAL
SHUT OFF THE GAS BEFORE
WARNING:
DURING SERVI CING MUST BE CHECK E D FOR
LEAKS. CHECK WITH A SOAP AND WATER
SOLUTION (BUBBLES). DO NOT USE AN OPEN
FLAME.
NOTE:
servi ceable and should not be di sassembl ed. Once
the problem has been isolated to t his component,
replace it. Do not attempt to repair the assembly.
1. Open the cabinet door to access the Pilot gas
valve.
2. Disconnect the lead wires.
3. Remove pilot gas tubing from the top of the
valve (outlet side).
4. Remove the valve from the gas supply piping.
5. Reverse proc edur e to install and adjust pilot
pressure as outlined under "G A S P ILOT
PRESSURE ADJUSTMENT" in "SERVICE
PROCEDURES AND ADJUSTMENTS".
ALL GAS JOINTS DISTURBED
Gas combination control valves are not
MAIN GAS VALVE
WARNING:
POWER TO T HE MACHINE AT THE MAIN
CIRCUIT BO X. P LA CE A TAG ON THE CI RCUIT
BOX INDICATING THE CIRCUIT IS BEING
SERVICED.
WARNING:
BEFORE SERVICING THE UNIT.
WARNING:
DURING SERVI CING MUST BE CHECK E D FOR
LEAKS. CHECK WITH A SOAP AND WATER
SOLUTION (BUBBLES). DO NOT USE AN OPEN
FLAME.
NOTE:
servi ceable and should not be di sassembl ed. Once
the problem has been isolated to t his component,
replace it. Do not attempt to repair the assembly.
1. Open the cabinet base door to access the mai n
gas valve.
2. Disconnect the lead wires.
3. Separate the uni on above the gas valve (outlet
side).
4. Remove the valve from the gas supply piping.
5. Reverse proc edur e to install and adjust
manifold pressure as outlined under "GAS
MANIFOLD PRESSURE ADJUSTMENT" in
"SERVICE PROCEDURES AND
ADJUSTMENTS".
DISCONNECT THE ELECTRICAL
SHUT OFF THE GAS SUPPLY
ALL GAS JOINTS DISTURBED
Gas combination control valves are not
F24700 (October 2001)Page 17 of 68
VHX SERIES STEAMERS - REMOVAL AND REPLACEMENT OF PARTS
BURNER HEAD ASSEMBLY
WARNING:
POWER TO T HE MACHINE AT THE MAIN
CIRCUIT BO X. P LA CE A TAG ON THE CI RCUIT
BOX INDICATING THE CIRCUIT IS BEING
SERVICED.
WARNING:
BEFORE SERVICING THE UNIT.
1. Remove the pressure gauge tubing and power
cable f r om the rear of the control panel then
remove the panel.
2. Disconnect the spark igniti on c able from the
ignitor termi nal.
3. Disconnect pilot gas tubing from the air
pressure switch tee.
4. Separate the uni on above the main gas v alve
and remove the gas v alve piping assembly .
NOTE
assumes the use of a gas line quick connect or
union at the gas supply inlet to the steamer.
5. Remove the screws from the burner head
assembly end plate and pull the assembly out
from the complete burner assembly .
DISCONNECT THE ELECTRICAL
SHUT OFF THE GAS SUPPLY
: Removal of the gas valve piping assembly
3. Remove the four nuts from the burner tube
assembly then slowly
out from the heat exchanger.
pull the assem bly straight
6. Reverse proc edur e to install and c hec k for
proper operati on.
COMPLETE BURNER
ASSEMBLY
WARNING:
POWER TO T HE MACHINE AT THE MAIN
CIRCUIT BO X. P LA CE A TAG ON THE CI RCUIT
BOX INDICATING THE CIRCUIT IS BEING
SERVICED.
WARNING:
BEFORE SERVICING THE UNIT.
1. Refer to steps 1 thr ough 4 under "BURNER
HEAD ASSEMBLY".
2. Remove the four nuts from c ombustion bl ower
mounti ng flange and remove blower from
burner tube assembly .
DISCONNECT THE ELECTRICAL
SHUT OFF THE GAS SUPPLY
CAUTION: Use care w hile removing as to no t
damage the ceramic insulation surrounding the
burner.
4. Reverse proc edur e to install and c hec k for
proper operati on.
F24700 (October 2001) Page 18 of 68
VHX SERIES STEAMERS - REMOVAL AND REPLACEMENT OF PARTS
HEAT EXCHANGER
WARNING:
SERVICING THE UNIT.
WARNING:
DURING SERVI CING MUST BE CHECK E D FOR
LEAKS. CHECK WITH A SOAP AND WATER
SOLUTION (BUBBLES). DO NOT USE AN OPEN
FLAME.
1. Blowdown the boiler and, if nec essary, allow to
cool.
2. Disconnect the electric al power to the machine
at the main circuit box. Place a tag on the
circuit box indicating the circui t is being
serviced.
3. Remove the pressure gauge tubing and power
cable f r om the rear of the control panel then
remove the panel.
4. Disconnect the electric al lead wires exiting the
boiler control box from:
SHUT OFF THE GAS BEFORE
ALL GAS JOINTS DISTURBED
NOTE
: Removal of the gas valve piping assembly
assumes the use of a gas line quick connect or
union at the gas supply inlet to the steamer.
8. Remove the four nuts from c ombustion bl ower
mounti ng flange and remove blower from
burner tube assembly .
A. Auxiliary LLCO probe (Orange).
B. Burner ground (green).
C. Air pressure switch (yellow & yellow/white
stripe).
D. Main gas valve (purple & grey).
E. Pilot burner valve (red & grey).
F. Spar k ignition cable.
5. Remove bolts securing the boiler control box
(front ) to the base frame.
A. Lift up on left side of box and slide out.
6. Disconnect pilot gas tubing from the air
pressure switch tee.
9. Remove the four bolts connecting the
horizontal flue (left of boil er) to the flue
"transition" piece.
A. Separate the horizontal flue f rom flue
"transition" piece, leaving the horizontal
flue in place.
7. Separate the uni on above the main gas v alve
and remove the gas v alve piping assembly .
10. Rem ove the four nuts fr om the com plete
burner tube assembly then slowly
assembly strai ght out from the heat exchanger.
CAUTION: Use care w hile removing as to no t
damage the ceramic insulation surrounding the
burner.
11. Rem ove the flue "tr ansi tion" piec e from the
heat exchanger.
F24700 (October 2001)Page 19 of 68
pull the
VHX SERIES STEAMERS - REMOVAL AND REPLACEMENT OF PARTS
12. For c learance of the heat exchanger only,
remove the drain nut (petcock) and the lower
adjustment knob from the water level gauge.
A. Remove the remaining bolt s on the heat
exchanger then pull heat exchanger
straight out from the boiler.
13. To install heat exchanger:
A. Clean the m ating surfaces on the heat
exchanger and boi ler.
B. Install a new gasket on t he boiler side of
the mounting fl ange.
F24700 (October 2001) Page 20 of 68
C. Insert the heat exchanger bac k into the
boiler and line up the mounting holes
being careful not to disturb gasket.
D. At tach a 2" C-Clamp between the heat
exchanger mounting flange and the boiler
side mounting flange. Tighten clamp only
enough to allow start ing of bottom bolt into
mounti ng hole.
VHX SERIES STEAMERS - REMOVAL AND REPLACEMENT OF PARTS
: It may be necessary to use two clamps
NOTE
to draw the bottom of the heat exchanger cl ose
enough to be clamped. Start one c lamp at a 3
o’clock position then instal l other clamp near
the bottom. Once the bolts are tight enough, CClamp will fall away.
E. Install two bolts at the bott om and two
bolts at the t op on the heat exchanger
flange and tighten the bolts a few turns at
a tim e. Starti ng wi th the bottom bolts,
tighten t he bolts in an alternating pattern
between the bottom and top for a flush
mounti ng of the heat exchanger flange
and an even compression of the gasket.
NOTE:
hand, clean out the threads with the proper si z e
tap.
F. O nc e those bolts are tight, install the two
If a bolt is not threading in properly by
bolts to the left and t he two bolts to the
right on the heat exchanger flange. On the
left side, be sure to install the rectangular
flue gas pl ate then tight en the bolts in an
alternating pattern.
15. Star ting at step 12, reverse procedure t o install
the remaining components.
16. Check for water leaks and proper oper ation.
COOKING COMPARTMENT
DOOR(S)
Removal
1. Remove top cover.
2. Open the door.
3. Pull hinge rod up.
4. Reverse the procedure to install, m ak ing sure
the door bushings are in place.
Gasket
1. Open the door.
14. To install flue "transition" pi ec e:
A. Clean the m ating surfaces on the
"transition" piece and the heat exchanger
face.
B. Install new gasket on t he " transition" piece
then secure to the heat exchanger using
the remaining bolts.
2. Remove screws from t he gasket plate.
3. Pull t he gasket plate out from the door housing
and remove the gasket.
4. Position the new gasket on the gasket plate
and rever se t he pr oc edur e to install . Adjust the
door as outlined in " DOOR SEALING
ADJUSTMENT" under "COOKING
COMPARTMENT".
NOTE:
this will compress the gasket excessively and
interfere with proper door seal ing.
NOTE:
as nicks or cuts, will cause steam leakage.
Do not ov er tighten gasket plate screws as
Damage to the gasket sealing surface, such
F24700 (October 2001)Page 21 of 68
Loading...