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SERVICE MANUAL
HEAVY DUTY GAS GRIDDLES
MODELS
924RX MSA24
936RX MSA36
948RX MSA48
960RX MSA60
972RX MSA72
948RX
This Manual is prepared for the use of trained Vulcan Service
Technicians and should not be used by those not properly qualified.
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 s
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GENERAL TABLE OF CONTENTS GENERAL ................................................................................ 3 Introduction ............................................................................ 3 Installation ............................................................................ 3 Operation ............................................................................. 3 Cleaning .............................................................................. 3 Specifications ....
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GENERAL GENERAL The griddle and its parts are hot. Use care when operating, cleaning or servicing the griddle. monitored by thermocouples and pilot safety valves. INTRODUCTION If the pilot goes out, the safety valve will shut-off the gas supply to the pilot and main burners. In the event This Service Manual covers specific service of a failure of the electronic ignition system, it is information related to the models listed on the front possible to ignite the pilots with an outside source cove
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GENERAL TOOLS • Standard set of hand tools. • VOM with A/C current tester (any quality VOM with a sensitivity of at least 20,000 ohms per volt can be used). • Temperature tester (thermocouple type). • U-Tube or Digital Manometer. • Thread sealant suitable for use with natural or propane gas. 924RX SHOWN • Aluminum Foil Tape - McMaster Carr Part 1. Burner assembly No.7631421 or equivalent. 2. Electric igniter (RX only) • Adapter to test thermocouple, Johnstone Supply Part No. H23-226 or equivalen
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REMOVAL AND REPLACEMENT OF PARTS REMOVAL AND REPLACEMENT OF PARTS Back Panel COVERS AND PANELS Front Panel NOTE: It will be necessary to remove the back panel 1. Turn all thermostats to off position, loosen set when changing a burner or to remove excessive screw securing thermostat knobs and pull off grease build up from flue area. knobs. 1. Disconnect gas supply at griddle. 2. Remove screws securing back panel to griddle. 3. Install in reverse order. MOMENTARY POWER SWITCH (900RX) NOT IN OFF P
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REMOVAL AND REPLACEMENT OF PARTS 2. Measure distance between manifold pipe and ELECTRIC IGNITER (900RX) valve for reassembly later. NOTE: Ignition wires must be routed in front of valves as shown to prevent them from touching hot heat shield. 1. Remove FRONT PANEL. 2. Push tab to release igniter from frame and pull out of unit. 3. Disconnect all gas lines and thermocouple from valve. 4. Remove valve from unit. 5. Transfer fittings from old valve to new valve. Use thread sealant on assembly. 6.
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REMOVAL AND REPLACEMENT OF PARTS 3. Remove screws securing thermostat mounting 10. Carefully insert orifice into burner and secure bracket to frame. thermostat mounting bracket to frame. 4. Pull capillary tube out from underneath griddle plate. 5. Transfer fittings from old thermostat to new 11. Inlet to burner must be straight. Adjust thread thermostat. Use thread sealant. on orifice and/or extension to close gap 6. Transfer thermostat mounting bracket to new between orifice and burner to 1/16
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REMOVAL AND REPLACEMENT OF PARTS BURNER PILOT, THERMOCOUPLE ASSEMBLY 1. Remove FRONT PANEL. 2. From underneath the front of the griddle, remove screw securing pilot assembly bracket. 1. Remove FRONT PANEL and REAR PANEL. 2. Disconnect gas supply at griddle. 3. Remove screw securing burner to wall. VIEW FROM REAR OF UNIT TO SEE PARTS 3. Carefully lift to disengage bracket from slot and work assembly down to access parts. 4. Service assembly as required and assemble in reverse order being sure br
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SERVICE PROCEDURES AND ADJUSTMENTS SERVICE PROCEDURES AND ADJUSTMENTS 2. Set thermostats to 350°F and allow to stabilize. CALIBRATION 3. Record the temperature tester readouts for Level each zone for 3 cycles. The griddle must be level (side-to-side and Temperature Temperature Turn-Off + front-to-back) during operation to ensure proper Tester turn-off Tester turn-on Turn-On divide performance. Improper leveling can result in uneven deg F deg F by 2 = average temperature distribution, cold spots
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SERVICE PROCEDURES AND ADJUSTMENTS GAS PRESSURE MEASUREMENT 1. Turn the gas supply off at a manual shutoff valve. 2. Remove the control panel. 3. Remove the pressure tap plug and attach manometer. 4. Turn gas back on. Never adjust the screw in the center of the thermostat shaft. This will ruin the factory calibration; 5. Light pilot(s). the thermostat will no longer operate properly and 6. Turn all thermostats on to the maximum setting will need to be replaced. so that all burners are on. 8. On
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SERVICE PROCEDURES AND ADJUSTMENTS The supply pressure (upstream of the regulator) should be 7-9” W.C. for natural gas and 11-12” W.C. for propane gas. At no time should the griddle be connected to supply pressure greater than ½ psig (3.45 kPa) or 14” W.C. Graphic shows pressure plug location. NOTE: MSA models are in same locations. There are no shut off valves. BURNER ADJUSTMENT For efficient burner operation, it is important that a proper balance of gas volume and primary air supply is maintai
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SERVICE PROCEDURES AND ADJUSTMENTS 8. Verify thermocouple output voltage. THERMOCOUPLE TEST A. If 25 - 35 millivolts is measured, the 1. Unscrew thermocouple fitting from safety valve. thermocouple is functioning properly. B. If less than 17 millivolts is measured, install a replacement thermocouple. 9. Remove test adapter. 2. Install thermocouple test adapter finger tight plus a quarter turn. 3. Install thermocouple into test adapter finger tight plus a quarter turn. NOTE: Over tightening can
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ELECTRICAL OPERATION ELECTRICAL OPERATION ELECTRICAL DIAGRAM Page 13 of 16 F25383 (510)
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ELECTRICAL OPERATION F25383 (510) Page 14 of 16
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TROUBLESHOOTING TROUBLESHOOTING SYMPTOMS POSSIBLE CAUSES No spark to ignite pilot gas. 1. Power cord unplugged. 2. Igniter switch malfunction. 3. Shorted electrode on ignitor. 4. Ignitor cable malfunction. 5. Interconnecting wiring malfunction. 6. Electric Igniter Module malfunction. Sparks but gas does not ignite. 1. Service gas valve closed. 2. Gas supply not purged of air. Depress pilot safety button until air is purged. 3. Gas supply off or insufficient gas pressure. 4. Adjust pilot valve t
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TROUBLESHOOTING F25383 (510) Printed in USA
