Vulcan-Hart ML-044937, ML-044936, ML-044962, ML-044969, ML-044961, ML-044939, ML-04494 Thermostats

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THERMOSTATS

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.

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Contents IMPORTANT FOR YOUR SAFETY SERVICE AND PARTS MANUALSIGNATURE SERIES VULCAN-HART COMPANY Snorkel Oven and/or Electric Ignition Oven with KX Thermostat TABLE OF CONTENTSINTRODUCTION Service NotesProduct Features and Descriptions Product Features and Descriptions Cont INSTALLATION REQUIREMENTS UNCRATING/SETUPGAS CONNECTIONS GAS PRESSURE REQUIREMENTSInstallation Requirements Cont Steps GAS PRESSURE CHECK PROCEDURESVENTILATION REQUIREMENTS DIAGRAM #4 PILOT ADJUSTMENTSDIAGRAM #1 DIAGRAM #3 DIAGRAM #2DIAGRAM #5 BURNER ADJUSTMENTSBATTERY INSTALLATION DIAGRAM #6 DIAGRAM #7 DIAGRAM #8 THERMOSTATS Standard Oven with FDTO Thermostat DIAGRAM #9DIAGRAM #10 CALIBRATION OF THERMOSTATSSnorkel Oven and/or Electric Ignition Oven with KX Thermostat Griddles with BJWA Thermostat BYPASS SCREW CALIBRATION SCREW DIAGRAM #11 DIAGRAM #12Spark System OVEN ELECTRIC IGNITION SYSTEMSSIGNATURE OVEN W/SPARK PILOT DIAGRAM #13DIAGRAM #14 SIGNATURE CONVECTION OVENW/ELECTRIC IGNITION SIGNATURE OVEN W/ELECTRIC IGNITION DIAGRAM #15DIAGRAM #16 BRASS VALVESVALVE DIAGRAM #19 DOORS, DOOR SEALS, HINGES AND COUNTERWEIGHTSDIAGRAM #17 DIAGRAM #18ORIFICE, LP BURNERORIFICE, NAT All sizes are rated for sea levelCLEANING PROCEDURES Cleaning Tips SCHEDULED MAINTENANCE Recommended Service FrequencyInspection Items TROUBLESHOOTING ProblemProbable Cause Griddle will not heat evenly Product sticking to griddle TROUBLESHOOTING Gas odor Charbroiler will not heat evenly Repeated component failure Stainless steel turning blue Stainless steel turning brown Standard Burners PARTSStandard Burner Parts 426745-1KNOB CONTROL Hot Tops/Fry Tops Hot Tops/Fry Tops Parts 426745-1KNOB CONTROL French Top French Top Parts 426745-1KNOB CONTROL Convection Oven Standard Oven788278A 788276PANEL Oven PartsControl System Convection Oven Control System Standard Oven S TYPE Control System Parts ListBody Parts/Shelves Risers 788382A Body Parts/Shelves Risers Parts List 788382A1 788382A2 788382A3Riser Kit Without Shelf P/N 788266A Riser Kit With Single Shelf P/N 788365A Double Deck Riser Kit Without Shelves P/N 788368A Double Deck Riser Kit With Shelves P/N 788368A FORM 31203 Rev. A March