Vulcan Hart V436S User Manual
SERVICE AND
PARTS MANUAL
SIGNATURE SERIES
MODEL MODEL MODEL
OVEN STD IGNIT ML-044905 VSB36IR ML-044936 VIR35M ML-044961
STD OVEN ML-044906 ML-044937 VIR36FM ML-044962
CONV OVEN ML-044907 VRBS48 ML-044938 VCB25M ML-044963
VCB25S ML-044908 VRBS60 ML-044939 VCB36M ML-044964
VCB36S ML-044909 VRBS72 ML-044940 VCB47M ML-044965
VCB47S ML-044910 VRBS96 ML-044941 VCB36 ML-044966
VGF18 ML-044911 VRBR36 ML-044942 VCB36C ML-044967
VS12T ML-044912 VRBR48 ML-044943 ML-044968
VS12F ML-044913 VRBR60 ML-044944 ML-044969
VS18T ML-044914 VRBR72 ML-044945 VO236 ML-044970
VS18F ML-044915 VRBR96 ML-044946 ML-044971
VS24T ML-044916 VIR36 ML-044947 ML-044972
VS24F ML-044917 VIR36C ML-044948 ML-044973
VS36T ML-044918 VIR36S ML-044949 ML-044974
VS36F ML-044919 VIR36F ML-044950 ML-044975
VS12S ML-044920 VIR36FC ML-044951 ML-044976
VS18S ML-044921 VIR36FS ML-044952 ML-044977
VS24S ML-044922 VRB36 ML-044953 ML-044978
VS36S ML-044923 VRB36C ML-044954 ML-044979
VS12M ML-044924 VRB36S ML-044955 VCM24R ML-135124
VS18M ML-044925 VRB36F ML-044956 VCM36R ML-135126
VS24M ML-044926 VRB36FC ML-044957 VCM48R ML-135127
VS36M ML-044927 VRB36FS ML-044958 VCM60R ML-135128
VFM18 ML-044928 VRB36M ML-044959 VCM72R ML-135129
VSB36R ML-044935 VRB36FM ML-044960 VCM84R ML-135130
IMPORTANT FOR YOUR SAFETY
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 PROCEDURES DESCRIBED IN THIS MANUAL.
THIS MANUAL IS NOT INTENDED TO BE ALL ENCOMPASSING. IF YOU HAVE NOT ATTENDED
A VULCAN SERVICE SCHOOL FOR THIS PRODUCT, 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-HART COMPANY IS PROHIBITED.
VULCAN-HART COMPANY, P.O. BOX 696, LOUISVILLE, KY 40201-0696, TEL. (502) 778-2791
– 1 –
FORM 31203 Rev. A (March 2002)
– 2 –© VULCAN-HART COMPANY, 2002
TABLE OF CONTENTS
INTRODUCTION .................................................................................................................................................... 4
Service Notes ........................................................................................................................................... 4
Product Features and Descriptions .......................................................................................................... 4
UNCRATING/SETUP ............................................................................................................................................. 6
INSTALLATION REQUIREMENTS ....................................................................................................................... 6
GAS CONNECTIONS ............................................................................................................................................ 7
GAS PRESSURE REQUIREMENTS .................................................................................................................... 7
GAS PRESSURE CHECK PROCEDURES .......................................................................................................... 8
Steps ......................................................................................................................................................... 8
VENTILATION REQUIREMENTS ......................................................................................................................... 9
PILOT ADJUSTMENTS........................................................................................................................................10
BURNER ADJUSTMENTS ...................................................................................................................................10
BATTERY INSTALLATION ..................................................................................................................................12
THERMOSTATS ...................................................................................................................................................15
CALIBRATION OF THERMOSTATS ...................................................................................................................16
Standard Oven with FDTO Thermostat ...................................................................................................16
Snorkel Oven and/or Electric Ignition Oven with KX Thermostat ..........................................................17
Griddles with BJWA Thermostat .............................................................................................................18
OVEN ELECTRIC IGNITION SYSTEMS .............................................................................................................20
Spark System ..........................................................................................................................................20
BRASS VALVES ..................................................................................................................................................24
DOORS, DOOR SEAL, HINGES AND COUNTERWEIGHTS .............................................................................25
Door Removal/Counterweight Replacement ............................................................................................25
CLEANING PROCEDURES ..................................................................................................................................27
Cleaning Tips ...........................................................................................................................................28
SCHEDULED MAINTENANCE .............................................................................................................................29
Recommended Service Frequency .........................................................................................................29
Inspection Items ......................................................................................................................................29
TROUBLESHOOTING ..........................................................................................................................................30
PARTS ..................................................................................................................................................................35
– 3 –
INTRODUCTION
Service Notes
The information in this manual is not intended to be all inclusive, rather it is a guide to the applications,
specifications and requirements of the Vulcan-Hart appliance.
Vulcan-Hart appliances are not any different in concept, components or application than many other appliances.
Vulcan-Hart appliances are designed to provide years of high performance. It is imperative that the installation
requirements, operating guidelines and maintenance procedures be followed to ensure long life and maximum
performance.
If the installation and/or appliance has not met the requirements outlined in this manual, please notify the VulcanHart Company, the end user and all other parties involved.
Product Features and Descriptions
The Signature Series Range line is an extra heavy-duty product, commonly referred to as hotel and/or institutional
cooking equipment.
The gas line is a 1
1
/4" front manifold, battery-type appliance. Chassis come in a variety of widths: 12", 18", 24"
and 36".
Top configurations available:
• Open burners in 12" and 18" sections
• Cast-iron hot tops in 12" and 18" sections
• Manual and thermostat griddles in 12" increments
• Graduated hot top (French top)
Standard and convection ovens are available on 36" chassis only.
On the 12", 18" and 24" chassis, the base of the oven is called a skeleton which is an open storage compartment.
The third configuration is a modular unit. It has a top section without a base and is mounted to an angle iron base
with 1 1/4" pipe legs.
OPEN BURNERS - The standard burner comes rated at 30,000 BTU/hr with a four slot, lift-off burner cap. There
are four other types of burner caps available. The no-slot types are used for large diameter cookware. There are
8-, 12- and 16-slot caps for direct centered heat used in sauté applications.
HOT TOPS - Full hot tops are rated at 35,000 BTU/hr and are available in 12" and 18" widths. Half hot tops (rear
only) are rated at 17,500 BTU/hr and are also available in 12" and 18" widths.
GRADUATED HOT TOPS - (French Top) This configuration is rated at a total of 50,000 BTU/hr. The large burner
is rated at 25,000 BTU/hr. The medium burner is rated at 14,000 BTU/hr and the small burner is rated at 11,000
BTU/hr.
GRIDDLES - Rated at 30,000 BTU/hr per burner. Manual control is standard. BJWA modulating thermostats are
available. Griddles are in 12" increments with one manual valve or thermostat per 12" section.
STANDARD OVEN - Rated at 40,000 BTU/hr. The interior dimension is 27" wide x 28 1/2" deep x 14 1/2"
high and
is supplied with one oven rack. The rack guides have four positions. The door is counterbalanced. The thermostat
is a modulating FDTO type with a temperature range of 250°F to 500°F degrees.
– 4 –
Product Features and Descriptions (Cont.)
1
SNORKEL CONVECTION OVEN - Rated at 30,000 BTU/hr. The interior dimension is 26
/4" wide x 23” deep and
14" high. The oven cavity is fully porcelainized. The door is also counterbalanced. Three oven racks are supplied
and the rack guides have four positions. The thermostat is a “snap action” KX type with a temperature range of
200°F to 500°F degrees. There is a 1/4 HP fan motor that requires 115 Volt minimum 15 amp service.
LEGS/CASTERS - Standard units are supplied with four 6" legs. For curb installation, leveling bolts are available.
Casters are available with 3" or 5" diameter wheels. Legs, casters or curb bolts are all 5/8" x 11 stems.
BACK RISERS - The standard unit is equipped with a 6" stainless steel stub riser. Also available are single and
double-deck risers with or without shelves and reenforced high shelves capable of mounting a Cheesemelter or
Salamander broiler. Another option is 48", 60" and 72" back risers in the same configurations capable of spanning
more than one unit. These wider back risers are special order only. All back risers are attached to the units via
a 2" x 4" female receiver on the top rear of the chassis and all high shelves/stub risers are interchangeable.
EXTERIOR FINISHES - The standard finish is black powder coat paint. All chassis’s are powder coated prior to
assembly. The most common exterior finish is stainless steel on the front. Stainless steel sides are available as
an option. Cast-iron open burners and grates are painted with a light coat of water based enamel. The water-based
enamel is intended to protect the raw cast iron during transit and storage only. Cast iron hot tops and steel griddle
plates are coated with a USDA-approved oil that must be removed prior to operation.
SPREADERS - These are non-functional items that are designed to offer a work surface between appliances and/
or a place to locate a pressure regulator in a battery line up. The standard spreader comes with the continuous gas
manifold, back riser and a top surface only. A front apron is available.
GAS CONNECTIONS - The standard unit is supplied with a 1
1
/4" front manifold with a male union fitting on the
left side of the appliance, and the female union fitting is on the right side of the appliance. As an option, a rear gas
tailpipe connection is available in either 1 1/4" or 3/4". Also this rear gas connection can be used to interconnect a
cheese melter or salamander broiler that is mounted to the re-enforced high shelf. Manifold caps and cover plates
are available for stand-alone units or battery end units.
MISCELLANEOUS and SPECIALS - There are many other configurations available in the Signature line including
models for back-to-back island installations. Special wide and/or long bull noses to span up to 108" in length and
8 3/4" in width. Additionally, back risers can be special ordered to span up to 72" in width.
Whenever dealing with any unit or configuration that seems unfamiliar, always secure the serial numbers and relay
that information to the factory for the specifics of the appliance.
Also available in the Signature line are double-stacked standard ovens, fryers, pasta cookers, single and doubledeck top-fired broilers and refrigerated bases. Only Vulcan-Hart Cheesemelters and Salamander broilers can be
mounted to the Signature line.
– 5 –
UNCRATING/SETUP
All Vulcan-Hart appliances are inspected and tested for function before leaving the factory. The transportation
company assumes responsibility for safe delivery of the shipment. Should an appliance arrive with apparent and/
or hidden damage, see the freight damage section of this manual.
• Uncrate the appliance; carefully remove all tie-down straps and packing material.
• Locate and identify any and all loose pieces such as oven racks, rack guides, casters, legs, pressure
regulator, back shelves and owner's manual.
• Locate the rating plate and check the specifications (gas type/electrical). If they do not match the utility
connections, do not proceed with the installation. Contact the dealer and/or Vulcan-Hart Customer Service.
• Note the model and serial number of the appliances and retain for future reference.
• Place the appliance in the proximity of its final location, install legs/casters and then inspect gas
connection points for obstructions and/or debris.
• Place the unit in its final location. Using a carpenter’s level, on the oven bottom or a solid portion of the
chassis, check the appliance to ensure it is level from side to side and front to back. Using the bullet foot,
level as necessary.
• For multiple unit installations (battery installations) see the battery installation section of this manual.
• Casters are non-leveling. If the floor is more than
1
/8" out of level, it is recommended that casters not be
used.
INSTALLATION REQUIREMENTS
The installation must allow for adequate clearances for service and operation with a minimum of 36" in front of the
appliance.
Models with 30,000 BTU burners must maintain 20" on the left and right sides as well as 2" in the rear to combustible
materials. The older models with 20,000 BTU burners require 6" on the left and right sides as well as 2" in the rear
to combustible materials. For non-combustible locations the clearances, are 0" left, right and rear.
Snorkel convection oven models require additional clearances in the rear for the fan motor to be able to cool itself,
with a minimum of 2". When snorkel ovens are mounted on curbs and/or without legs, there must be at least 6"
of airspace behind the appliance.
There must be an adequate supply of fresh air, based on BTU consumption and exhaust volume to ensure proper
combustion as well as maximum performance.
The appliance or line up must be installed so the flow of combusted air/flue gasses are not obstructed or disturbed
in any way. Make up air, fans or drafts directed at the rear of the appliance will obstruct, inhibit or disturb the flow
of flue gasses. This will affect the oven and/or griddle performance, cause poor combustion and can damage the
operating components, which will void the appliance warranty. Do not place wall mounted objects over the
appliance.
Wall-mounted objects, appliances or shelves above the appliance will block the natural path of the flue gasses,
which can slow or stop the appliance from fluing. This will cause problems and damage to operating components,
which will void the appliance warranty.
Make up air, fans or drafts directed at the top or front of the appliance will cause problems with open burners, such
as delayed ignition and poor performance.
– 6 –
Installation Requirements (Cont.)
All appliances must be vented to the outside. Depending on local codes, the specifics may vary. Check with local
authorities. Fluing occurs because heat rises vertically, which has no force behind it. Any obstruction or
disturbance will negatively affect the appliances ability to flue itself. Make up or fresh air should be present low
and in the front of the appliance.
Gas connector hoses shall be commercial grade and have the capability of supplying at least 10% more fuel than
the maximum BTU consumption of the appliance or line up. Furthermore, gas connector hoses shall be no smaller
than 3/4" inside diameter.
When units are mounted on casters, the gas connector hose must comply with the current standard for movable
gas appliances. Furthermore, the installation must provide for a restraining cable/chain device to limit the
movement of the appliance or line up.
GAS CONNECTIONS
CAUTION: ON ALL GAS SUPPLY CONNECTIONS ANY PIPE JOINT COMPOUND USED MUST BE RESISTANT
TO THE PROPERTIES OF PROPANE (LP) GAS.
Before making any gas connections, be sure to check for obstructions or debris in the manifold pipe and union
fitting. Once the appliance has been connected and the air has been purged from the system all the fittings and
connections must be tested for leaks using a soap solution, or an appropriate gas leak-sensing instrument.
WARNING: DO NOT USE AN OPEN FLAME TO CHECK FOR GAS LEAKS.
If a gas leak is detected and cannot be stopped, shut off gas supply to the appliance or line up and contact your
local gas provider or an Authorized Servicer.
GAS PRESSURE REQUIREMENTS
Natural gas pressure should be 5" Water Column (W.C.) plus or minus 1/2" W.C.
Propane (LP) gas pressure should be 10" W.C. plus or minus 1/2" W.C.
On units that have infra-red burners such as Salamanders and Cheesemelters, the gas pressure variables are
slightly different, plus 1/2" W.C. minus .2" W.C. Example: on natural gas, 4.8" to 5.5" W.C., on propane (LP) 9.8"
to 10.5" W.C.
All gas appliances must have a gas pressure regulator installed. In order for the pressure regulator to perform
properly, the supply pressure must be greater than the operating pressure. For example, most cities supply 7" to
9" W.C. of natural gas pressure to a building.
Propane (LP) systems should supply 11" to 12" W.C. The appropriate pressure regulator will provide the correct
pressure to the unit or line up.
Sometimes even though the gas pressure is correct, the appliance may not be able to function properly because
the gas supply piping may be too small and is not able to supply the volume of gas required. It is recommended
that the piping be able to supply a minimum of 10% more fuel than the maximum BTU consumption of the appliance
or line up.
Because of the size of the Signature manifold (1 1/4") when a 1 1/4" pressure regulator is used, up to three appliances
may be connected to one pressure regulator. For example, a battery line up of six units must be connected to two
gas pressure regulators. A single appliance can be connected to a 3/4" gas pressure regulator.
– 7 –
GAS PRESSURE CHECK PROCEDURES
Steps
1. Connect the manometer to the main gas manifold pipe of the appliance, or in a battery the center unit of
the line up. If the pressure reading is taken at the oven burner or anywhere other than the main gas manifold
pipe, the pressure drop can be 1" W.C. or greater and the test is invalid.
2. Fire up one burner and take a reading.
3. Fire up all the burners on the appliance and take a reading.
4. Fire up all the gas appliances on that supply line and take a reading.
5. At no time should the pressure drop more than 1/2" W.C.
If the pressure is set at the recommended setting and the pressure drop is slightly under, or 1/2" W.C., the regulator
can be adjusted up to the maximum, for example, a 5.5" W.C. for natural and 10.5" W.C. for propane (LP). However,
if the pressure drop is greater than 1/2" W.C., it is likely a lack of volume due to too small of a supply line. Check
with the gas provider for the proper size gas line.
– 8 –
VENTILATION REQUIREMENTS
Depending on local codes, ventilation requirements may vary. A basic formula is as follows: 100 to 150 CFM (cubic
feet per minute) per square foot of floor space that the appliance or line up occupies. For example, one standard
six burner unit, which measures 36" wide by 38" deep, equals approximately 9 square feet of floor space, therefore
900 to 1,350 CFM of exhaust is required.
Units with charbroilers may require more CFM exhaust; check with local authorities.
The hood should extend a minimum of 6" over all exposed sides of an appliance or line up. Seldom can the units
be without rear clearance, so figure 4" in the rear.
For every cubic foot of gas that is burned, 11 cubic feet of by-products are produced. These by-products must be
vented to the outside.
Ventilation systems need to be properly balanced to ensure that all the by-products are exhausted. There must
be an adequate supply of fresh air for proper combustion and still a very slight negative pressure in the kitchen.
Sometimes a hood system will be operating perfectly as per its manufacturer’s specifications, however there is
still a problem with the gas-cooking appliance. The hood system may not be compatible with the gas appliance
under it. In these instances, the service contractor for the hood system and the appliance Servicer will have to
work together to attempt to correct the problem. If it is determined that the hood system is not compatible with
the appliances under it, it is imperative that this information be communicated to the end user, the dealer and all
parties involved, especially the Vulcan-Hart Company.
If the fresh air system (make up air) is such that ovens and griddles are experiencing fluing problems, there will
be component failures due to excessive heat. If the open burners are fluttering or blowing around due to make up
air being directed at the top or front of the unit delayed, no ignition will occur, and the appliance’s performance will
be severely affected. If it is determined that any of these conditions exist, the appliance warranty will be voided.
Some cities allow the use of a direct vent system in lieu of a motor-driven exhaust system to vent a bake oven.
Check with local authorities.
To increase appliance performance and minimize energy consumption of the ventilation system:
• Add side panels on canopy hoods.
• Avoid make up air diffusers close to hood or re direct air away from top and/or rear of appliance.
• Add multi-or variable-speed exhaust and make up air fan controls.
– 9 –
PILOT ADJUSTMENTS
After all connections/fittings have been checked for gas leaks and no leaks are found, the pilots can be lit. Locate
each pilot and the corresponding pilot adjustment valve. Light the pilots and adjust them up or down as necessary.
The flame should be only high enough to ignite the corresponding burner within 3 or 4 seconds maximum.
Mushroom head-type pilots are used on open burners, griddles and hot tops. The flame should be only about the
size of a dime. This type of pilot will burn yellow; that is the reason they should be as small as possible and still
be able to ignite the burner, within 3 or 4 seconds, maximum (Diagram #2).
Orifice pilots with thermocouples or flame switches are used on ovens. The flame should be large enough to
completely engulf the tip of the thermocouple/sensor and make the tip of the thermocouple/sensor glow red-hot.
Orifice pilot flames should be sharp, well-defined, two-tone blue when burning natural gas. However, when burning
propane (LP) there may be a tiny yellow tip to the flame. This yellow tip should be no more than 10% of the total
flame size (Diagram #1).
All gas burners should ignite within 3 to 4 seconds, maximum. All burners are tested at the factory prior to shipment.
However, fine tuning adjustments may be necessary to accomplish 3 to 4-second ignition at the installation site.
Most gas burners have an air shutter. There are two types of air shutters, the cap or disk type (Diagram #3) and
the sleeve type (Diagram #4). The cap or disk type is used on burners with cast iron venturis. The sleeve type is
used on tubular steel burners and/or burners with tubular steel venturis. All burners are tested and the air shutters
are set at the factory prior to shipment. However the factory cannnot make the fine tuning adjustments that may
be necessary at the actual installation.
DIAGRAM #1
DIAGRAM #3
DIAGRAM #2
DIAGRAM #4
– 10 –
BURNER ADJUSTMENTS
When using natural gas, the air shutter will be approximately 50% open. On propane (LP) the air shutter will be
approximately 90% open.
If the flame is soft, lazy or yellow, there is not enough primary air and the air shutter needs to be opened up. In
the event this does not solve the situation, check the burner for obstructions and clear as necessary. If the flame
is lifting off the burner, there is too much primary air and the air shutter needs to be closed down (Diagram #5).
If grates, hot tops or oven bottoms have been removed, be sure to recheck flame adjustments with these items
in place as the flame characteristics may change and additional adjustments may be necessary. Always recheck
burner flames after the grates, hot tops and oven bottoms are in their proper place.
DIAGRAM #5
– 11 –
BATTERY INSTALLATION
1. Remove grates, hot tops, knobs, front manifold cover and bull nose (Diagram #6).
2. Slide open burners and/or hot tops off the orifice/valve, but do not remove them from burner box. It is not
necessary to remove griddle burners unless the griddle plate is already off the unit. Be careful that the
weight of the griddle burner or burners does not cause the manifold pipe to rotate when the manifold
mounting clamps are loosened.
3. Loosen manifold mounting clamps enough that the manifold pipe is free to move (Diagram #7).
4. Slide units together and level with bullet feet, as necessary, so that the manifold pipes mate up. If the pipes
do not mate up, the units are not level. Do not use the manifold mounting clamps to compensate for
anything other than very minor adjustments (1/8" or less). Units on casters will not level up if floor is not
level. Casters must be installed wrench tight.
3. Engage the union nut with the opposing male union fitting and hand-tighten as much as possible until units
are mated up (Diagram #7).
4. Locate mounting holes in the riser and top frame, then bolt the units together using the appropriate length
1
/4" bolts (Diagram #8 on page14).
5. When all the units in the battery are connected, use a backup wrench on the manifold pipe to begin
tightening the unions.
CAUTION: DO NOT ALLOW THE MAIN MANIFOLD PIPE TO ROTATE, AS THIS WILL DAMAGE THE
PILOT LINES AND/OR VALVES AND MAY CAUSE GAS LEAKS.
6. Once all the units are bolted together and the unions are tight make sure all the valves are in the original
level position. Retighten the manifold pipe mounting clamps.
7. Reinstall and bolt bull noses together (Diagram #6).
8. Reinstall any burners that were removed. Reattach the pilots that were removed. Check that burners and/
or pilot lines and fittings are in their original position and have not been damaged.
9. Install pressure regulators as needed. No more than three units are to be connected to any one,11/4" gas
pressure regulator.
10. Connect battery to gas supply. Purge the air from the system. Check for leaks using a soap solution.
WARNING: DO NOT USE AN OPEN FLAME TO CHECK FOR GAS LEAKS.
11. Check and adjust gas pressure if necessary (see gas pressure adjustment and gas pressure check
sections of this manual).
12. Thoroughly check all units for packing material, protective coatings and manuals before lighting any pilots.
13. Begin lighting and adjusting pilot flames (see pilot adjustment section of this manual).
14. Check and adjust all burners as necessary (see burner adjustment section of this manual). All burners
should light within 3 or 4 seconds, maximum. It may be necessary to remove grates, hot tops, oven
bottoms and possibly the griddle plate to make the necessary adjustments.
15. At this point if no problems are noted the battery is ready to be started up. If any problems are noted they
must be corrected before the battery can be put into operation. AN AUTHORIZED SERVICER MUST
MAKE ALL REPAIRS to ensure the factory warranty is not compromised.
– 12 –
DIAGRAM #6
DIAGRAM #7
– 13 –
DIAGRAM #8
– 14 –
THERMOSTATS
The standard oven uses an FDTO-type, modulating thermostat. When first turned on, the flame comes on full
speed, approximately 1 1/4" to 1 1/2" tall. As the temperature approaches the set point, the flame slowly reduces
in size. When the temperature is achieved, the flame should be in bypass, approximately 1/8" tall. The bypass flame
will keep the oven temperature constant unless the door is opened and heat is lost.
When the oven needs to recover heat loss, the thermostat will allow the flame to slowly increase in size until the
temperature is again at the set point. Usually the thermostat does not require calibration, however it may need to
have the bypass flame set at the time of installation. The temperature accuracy of this thermostat is 25°F. For
calibration and/or bypass adjustment, see thermostat calibration section of this manual.
Snorkel and electric ignition ovens use a KX-type snap action thermostat. When first turned on, the flame comes
on full speed. When it achieves the set temperature, it shuts off. When 10°F to 15°F is lost, the thermostat will
come on full speed to recover the heat loss. Due to the fact the thermostat shuts completely off and the oven is
constantly venting heat off through the flue, the thermostat will cycle on and off throughout the cooking process.
The temperature accuracy of the KX thermostat is 15°F to 20°F. If calibration is required, see the calibration section
of this manual.
The thermostat used on griddles is a BJWA modulation type. When first turned on the flame comes on full speed,
approximately 3/4" to 1" tall. As the temperature approaches the set point, the flame is slowly reducing in size. When
the temperature is achieved, the flame should be in bypass. Bypass flame for griddles should only be big enough
to keep the burner lit all the way around, with little blue dots of flame.
This type of thermostat by design will allow the temperature to creep if the griddle is left idling, with no product
on the griddle, for a minimum of 50°F an hour. Therefore it is imperative that the bypass flame be correct. If the
bypass flame is not correct, the temperature will creep to 100°F to 200°F an hour. Temperature accuracy of the
BJWA thermostat is 25°F. For calibration/bypass adjustments see the calibration section of this manual.
NOTE: Calibrations and/or bypass adjustments require a good working knowledge of the components and system
as well as specific test instruments and should only be performed by authorized service personnel. When checking
calibrations on the BJWA griddle thermostat, it is necessary to begin the procedure when the griddle is cold.
Attempting to calibrate the BJWA griddle thermostat from other than a cold start is extremely difficult, as well as
time consuming, and can cause the temperature to be incorrect at a later time.
– 15 –
CALIBRATION OF THERMOSTATS
Field recalibration is very seldom necessary on new appliances, however older thermostats may require
calibration. Recaibration should only be considered when cooking results definitely indicate the thermostat is not
maintaining the set temperature. Before attempting recalibration, the temperature should should be checked with
temperature test instrument or a reliable thermometer.
Standard Oven with FDTO Thermostat
1. Place the test instrument sensor or thermometer in the center of the oven cavity and close the door.
2. Turn oven on, set the thermostat dial to 300 degrees and allow the oven to cycle several times (at least
20 minutes).
3. Turn the thermostat dial back to the lowest temperature setting. Check the bypass flame; it should be
1
/8" tall. Adjust bypass as necessary (Diagram #9).
4. Turn thermostat dial back to 325°F and allow 5 minutes for temperature to stabilize. If temperature is more
than 20°F different from the dial setting, calibrate as follows.
A. Remove dial and loosen the calibration plate screws until the calibration plate moves freely. Gently
attach dial and turn until the dial setting matches the actual oven temperature (Diagram #9).
B. Hold calibration plate. Gently remove dial and tighten calibration plate mounting screws. Apply
adhesive material to calibration screws
C. Replace dial and increase temperature 50°F. Allow 10 minutes and recheck the temperature.
D. If temperature is still more than 20°F different from the dial setting, the thermostat may need to be
replaced.
BYPASS SCREW
CALIBRATION SCREWS
CALIBRATION SCREW
DIAGRAM #10DIAGRAM #9
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