SERVICE MANUAL GAS COMBI OVENS MODEL ML VC10FGP 52444 VC10HGP 52441 VC20HGP 52442 VC10HGP SHOWN - 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.
COMBI OVEN TABLE OF CONTENTS GENERAL . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3 Lubrication . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
COMBI OVEN - GENERAL GENERAL INTRODUCTION TOOLS The procedures in this manual apply to all models unless specified otherwise. Standard • Standard set of hand tools. • Metric set of hand tools. • VOM with AC current tester (any quality VOM with a sensitivity of at least 20,000 ohms can be used). • Gear puller (to remove fan). • Temperature tester (thermocouple type). • Manometer Special • Red High Temperature RTV (544313 or 542949) for door seal and probes.
GAS COMBI OVEN - REMOVAL AND REPLACEMENT OF PARTS REMOVAL AND REPLACEMENT OF PARTS RACK GUIDE/ FILTER /EXHAUST ASSEMBLY 7. 20 level only. Loosen the wing nuts and lower the filler panel at the top of the exhaust assembly. Remove the racks (if equipped). 8. Push the rack guide to rear of oven to remove the rack guide tabs from from slots in the exhaust assembly (10 level). Lift up on exhaust assembly then pull forward at bottom to clear the dowel pins. 9.
GAS COMBI OVEN - REMOVAL AND REPLACEMENT OF PARTS COVERS AND PANELS 3. Lower the control panel, when the location pin is aligned with the slot, move forward . WARNING: DISCONNECT THE ELECTRICAL POWER TO THE MACHINE AT THE MAIN CIRCUIT BOX AND SHUT THE WATER SUPPLY AND GAS VALVE OFF. PLACE A TAG ON THE CIRCUIT BOX INDICATING THE CIRCUIT IS BEING SERVICED. Control Panel (10 Level) 1. Open the door. 2. Remove fuse access panel. 3.
GAS COMBI OVEN - REMOVAL AND REPLACEMENT OF PARTS Rear Panel 1. Remove 3 screws along the bottom of the panel. 2. Pull the left rear corner away from the oven and disconnect the ground wire from the panel. 3. Lower the panel to clear alignment pins and remove from the oven. 4. OVEN TEMPERATURE PROBE WARNING: 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.
GAS COMBI OVEN - REMOVAL AND REPLACEMENT OF PARTS CONTROL BOARD RELAY BOARD WARNING: 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. WARNING: 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. CAUTION: Certain components in this system are subject to damage by electrostatic discharge during field repairs.
GAS COMBI OVEN - REMOVAL AND REPLACEMENT OF PARTS Installation 1. Mount the motor to the back of the oven. Tighten the bolts enough to hold the motor in place, but allow some movement. BLOWER AND MOTOR Removal WARNING: 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. Remove the rack guide, filter and exhaust assembly as outlined under “RACK GUIDE/ FILTER/EXHAUST ASSEMBLY”. 2.
GAS COMBI OVEN - REMOVAL AND REPLACEMENT OF PARTS 6. Apply red high temperature RTV to the outer edge of the seal to help hold it in the recess and install the seal with the seal cover toward the oven cavity opening. 6. CAUTION: Remove all traces of motor seal grease from the motor shaft. 7. Remove the burner from inside oven cavity. NOTE: Seal the burner mounting plate with high temperature sealant.
GAS COMBI OVEN - REMOVAL AND REPLACEMENT OF PARTS BALL VALVE MOTOR 4. Remove the rear panel as outlined under “COVERS AND PANELS”. WARNING: 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. 5. Disconnect the lead wires to the water level probes. 6. Remove the hose from the water level regulator. 7. Remove the probe assembly from the top of the water level regulator. 8. Reverse procedure to install. 1.
GAS COMBI OVEN - REMOVAL AND REPLACEMENT OF PARTS NOTE: When installing the flue, seal the edges of the metal with high temperature sealant. VENT MOTOR WARNING: 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. 5. Disconnect the lead wires from the electrodes and the ground. 6. Disconnect the gas line. 1. Remove the right side panel as outlined under “COVERS AND PANELS”. 7.
GAS COMBI OVEN - REMOVAL AND REPLACEMENT OF PARTS Disassembly BOILER WARNING: 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. WARNING: SHUT OFF SERVICING THE UNIT. THE GAS BEFORE 1. Turn water supply to the boiler off and drain the boiler. 2. Remove the right side and rear panels as outlined under “COVERS AND PANELS”. 3. Remove the boiler burner as outlined under “BOILER BURNER”. 1.
GAS COMBI OVEN - REMOVAL AND REPLACEMENT OF PARTS OVEN DOOR HINGES DOOR HANDLE SWITCH WARNING: 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. WARNING: 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. Remove and disassemble the door as outlined under “OVEN DOOR”. 1.
GAS COMBI OVEN - REMOVAL AND REPLACEMENT OF PARTS DOOR LOCKING MECHANISM 2. Remove the motor, gear box and switch assembly from the locking mechanism. 3. Remove the two bolts from mechanism. 4. The springs, locking arm and bushings can be removed. 5. Reverse procedure to install. WARNING: 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. Replacement 1.
GAS COMBI OVEN - REMOVAL AND REPLACEMENT OF PARTS OVEN CAVITY SEAL OVEN CAVITY DRAIN SEAL WARNING: 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. WARNING: 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 door. 1. Open the door. 2. Pull the seal from the groove around the oven cavity. 2.
COMBI OVEN - SERVICE PROCEDURES AND ADJUSTMENTS SERVICE PROCEDURES AND ADJUSTMENTS WARNING: CERTAIN PROCEDURES IN THIS SECTION REQUIRE ELECTRICAL TEST OR MEASUREMENTS WHILE POWER IS APPLIED TO THE MACHINE. EXERCISE EXTREME CAUTION AT ALL TIMES. IF TEST POINTS ARE NOT EASILY ACCESSIBLE, DISCONNECT POWER, ATTACH TEST EQUIPMENT AND REAPPLY POWER TO TEST. COMBI STEAM OPERATION The combi mode is used when steam needs to be added to a bake mode.
COMBI OVEN - SERVICE PROCEDURES AND ADJUSTMENTS 4. 5. The RELAY test consist of selecting a particular relay (numbered between 1 and 11) with the temperature up and down keys. The selected relay is then energized for a maximum of 2 seconds when the temperature set key is pressed. The test may be exited at any time by pressing the “off” key and holding for a minimum of 3 seconds.
COMBI OVEN - SERVICE PROCEDURES AND ADJUSTMENTS CONTROL CONFIGURATION MODE • • The configuration mode can be entered only when the oven is off. Returning to the normal operating mode can be done at any time by pressing the “off” key. The selection are performed in a fixed sequence of: 1. Number of fan motors. (1 = 10 levels and 2 = 20 levels) 2. Degrees Celsius or Fahrenheit. 3. Date code of software version. 4. Total running time of the oven is displayed in the temperature display. 5.
COMBI OVEN - SERVICE PROCEDURES AND ADJUSTMENTS OVEN DOOR ADJUSTMENT 1. Turn the oven off. 2. Loosen the hinge screws enough that you can move the door but the door will stay in position when not being moved. 3. Position the door square with the oven, then tighten the hinge screws. 6. With the door in the closed position the roller should be cradled in the door lock arm hook. 7. Close the handle.
COMBI OVEN - SERVICE PROCEDURES AND ADJUSTMENTS SERVICE LIGHTS ELECTRODE GAP SETTINGS There are four lights at along the bottom of the control. When lit, they tell the operator that the oven needs service. The lights are, from left to right: WARNING: 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. Air Intake: Air flow to cavity burner is restricted, check filter. Turn oven off to reset light. 2.
COMBI OVEN - SERVICE PROCEDURES AND ADJUSTMENTS PRESSURE SWITCH CHECK 1. Set the pressure switch dial on 2. 2. Remove the screw from the test port and attach a manometer. 3. Check for 2"W.C. 4. Move the dial to obtain the 2"W.C. GAS PRESSURE ADJUSTMENT WARNING: 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.
COMBI OVEN - ELECTRICAL OPERATION ELECTRICAL OPERATION COMPONENT FUNCTION 1A Oven Control . . . . . . . Manages all functions of oven, takes input signals and performs outputs as required. 2A Relay Board . . . . . . . . Takes inputs from control to operate relays that control power to the components. 3A Cavity Burner Ignition Module Controls and monitors the cavity burner operation. 4A Boiler Ignition Module Controls and monitors the boiler burner operation. 5A Gas Valve (Cavity) . . .
COMBI OVEN - ELECTRICAL OPERATION 1SW Cavity Motor Reset Resets relay K10. 2SW Door Mech Switch . Allows door motor to operate to unlock door. 3SW Door Mech Switch . Allows door motor to operate to lock door. 4SW Cavity Vent Switch . Signals control, vent is opened or closed. 5SW Ball Valve Switch . . Signals control, ball valve is open. 6SW Ball Valve Switch . . Signals control, ball valve is closed. 7SW Air Pressure Switch Prevents the cavity burner from operating until 2"W.C.
COMBI OVEN - ELECTRICAL OPERATION COMPONENT LOCATION 10 Level 24
COMBI OVEN - ELECTRICAL OPERATION 20 Level 25
COMBI OVEN - ELECTRICAL OPERATION 4. SEQUENCE OF OPERATION - OVEN 5. Powering Control 1. Conditions A. Oven installed correctly B. High limit thermostats closed C. 120 VAC to oven 1) 18 VAC to control 2) 240 VAC to control D. Fuses good E. Door in closed position, but not locked. Handle positioned over door handle switch. F. Cavity vent closed G. Gas and water “on” 2. Turn Oven on. A. Door closing motor energized; door locked. B. Ball valve motor operates and positions ball valve in open position. C.
COMBI OVEN - ELECTRICAL OPERATION 1. The control can be in any mode and the door can be in any position. When the S87 goes into safety lockout, the spark ignition circuit is de-energized and the gas valve closes. The S87 will stay in safety lockout for 30 seconds. 2. Press the off key. 1. Power supplied from 24 volt transformer when thermostat calls for heat. 2. A 30 second purge time is initiated. 3. A “Trial for Ignition” cycle begins. A. Power to spark ignition circuit. B.
COMBI OVEN - ELECTRICAL OPERATION WIRING DIAGRAMS (10 LEVEL) 28
COMBI OVEN - ELECTRICAL OPERATION 29
COMBI OVEN - ELECTRICAL OPERATION WIRING DIAGRAMS (20 LEVEL) 30
COMBI OVEN - ELECTRICAL OPERATION 31
COMBI OVEN - TROUBLESHOOTING TROUBLESHOOTING OVEN TROUBLESHOOTING SYMPTOM POSSIBLE CAUSES Oven inoperative. Control displays do not light. 1. 2. 3. 4. Check main circuit breaker. F1, F2, F4, F6 or F7 open. Main transformer malfunction. Control inoperative. Service indicator on control lights. 1. 2. 3. 4. Blower motor inoperative. Air intake filter or motor malfunction. Cavity burner ignition circuit malfunction. Boiler burner ignition circuit malfunction. Temperature display flashes 1.
COMBI OVEN - TROUBLESHOOTING No spark at boiler burner. 1. 2. 3. 4. 5. 6. 7. Water level below earth probe Ignition transformer malfunction. Fuse on ignition module open. Ignition module in safety lockout. Ignitor probe out of position. Ceramic insulator on either electrode cracked. Ignition module malfunction. Pressure switch Service Light on. 1. Pressure switch not closing. A. Air intake filter plugged. B. Air intake motor inoperative. C. Ball valve in closed position. D. Pressure switch malfunction.
COMBI OVEN - TROUBLESHOOTING BURNER TROUBLESHOOTING 34
COMBI OVEN 35
COMBI OVEN Form 24578 (1/97) Printed in USA