MT1828 CONVEYOR OVEN SERVICE AND REPAIR MANUAL BLODGETT OVEN COMPANY www.blodgettcorp.com 50 Lakeside Avenue, Box 586, Burlington, Vermont 05402 USA Telephone (800) 331-5842, (802) 860-3700 Fax: (802)864-0183 PN M8560 Rev C (6/01) E 2001 --- G.S. Blodgett Corporation All rights reserved. Duplication of the information in this manual is prohibited without the consent of the Blodgett Service Department.
TABLE OF CONTENTS 1. INTRODUCTION Oven Specifications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Ventilation Requirements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Electrical Specifications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Gas Specifications . . . . . . . . . . . . . . . . . . . .
CHAPTER 1 INTRODUCTION
MT1828 OVEN SPECIFICATIONS VENTILATION REQUIREMENTS ELECTRICAL SPECIFICATIONS The hood should completely cover the unit with an overhang of at least 6” (15 cm) on all sides not adjacent to a wall. The distance from the floor to the lower edge of the hood should not exceed 7’ (2.1 m). The ventilation system should replace 80% of the exhaust volume with fresh make up air. TABLE 1 should be used as a guideline. NOTE: Three Phase hookup is not permitted on gas models.
MT1828 Installations outside the U.S. L1, L2, L3, neutral and ground. See FIGURE 2. Use a minimum of 8.37 mm2 copper stranded wire or larger for 3 phase and 21.15 mm2 for 1 phase. The MT1828G requires a 15 Amp, 50Hz, 1Φ, 240 VAC, 3 wire service consisting of L1, neutral and ground. See FIGURE 2. Use 90_C wire and size wire according to local codes. CE approved installations The MT1828G requires 15 Amp, 50Hz, 1Φ, 230 VAC, 3 wire service consisting of L1, neutral and ground.
MT1828 GAS SPECIFICATIONS GAS CONNECTIONS GAS REQUIREMENTS Domestic and General Export installations The firing rate for the MT1828G is 33,000 BTU/Hr. (9.7 kW/Hr.) The gas line should be large enough to accommodate the peak demand of all the gas appliances. TABLE 2 reflects a straight line, 50 foot run with no coupling restrictions and no other appliances drawing service. Gas line installations MUST conform to National Fuel Gas Code NFPA 54/ANSI Z223.1 Sec. 1.4 (Latest Edition).
CHAPTER 2 OPERATION
MT1828 COMPUTER CONTROLLER 1 2 9 3 8 7 6 5 4 FIGURE 1 CONTROL DESCRIPTION CONTROL OPERATION 1. DIGITAL DISPLAY --- Displays the time, temperature and controller related information. To turn the oven on: 1. Press and hold the ON/OFF key (2). The display reads OFF when the oven is idle. 2. The display flashes WAIT D LOW D SET D TIME D mmss. 3. The FAN and HEAT status lamps (9) light. The fans begin to run. The heat rises to the programmed temperature.
OPERATION PROGRAMMING PROCEDURES DISPLAY INFORMATION Programming the Cook Time: D 1. Press the PROGRAM/ENTER key (8). 2. Press the TIME key (7). The display reads PROG-? D SET D TIME-? D _ _ _ _. D 3. Use the NUMERIC keys (3) to enter the desired cook time. The display will read the numbers as they are entered. If an error is made, press the CLEAR key (4) and re-enter the number. D D 4. Press the PROGRAM/ENTER key (8) a second time to lock-in the new time.
MT1828 SEQUENCE OF OPERATION MT1828G DOMESTIC AND GENERAL EXPORT OVENS INTERNAL MOUNT --- M7296 REV B COMPONENT REFERENCE terminal of a single pole double throw thermal switch (5). NOTE: Refer to FIGURE 2 for component locations. 1. 2. 3. 4. 5. 6. 7. 8. 9. 10. 11. 12. 13. 14. 15. 16. 17. 18. 19. 3. When the belt stop relay (2) closes, 110 V.A.C. are sent to the motor control board (6) and the single pole single throw thermal switch (7).
FIGURE 2 2---4 19 19 12 19 19 19 17 1 5 6 2 11 3 4 13 7 18 18 8 15 14 16 9 10 OPERATION
MT1828 MT1828G DOMESTIC AND GENERAL EXPORT OVENS EXTERNAL MOUNT --- M9776 REV B COMPONENT REFERENCE motor contactor closes, power is also applied to the NIC terminal of a single pole double throw thermal switch (5). NOTE: Refer to FIGURE 2 for component locations. 1. 2. 3. 4. 5. 6. 7. 8. 9. 10. 11. 12. 13. 14. 15. 16. 17. 18. 19. 3. When the belt stop relay (2) closes, 110 V.A.C. are sent to the motor control board (6) and a single pole single throw thermal switch (7).
12 19 1 17 2 6 3 4 11 13 7 18 8 14 16 10 9 OPERATION FIGURE 3 2---6
MT1828 MT1828E DOMESTIC AND GENERAL EXPORT OVENS --- M6314 REV C COMPONENT REFERENCE OPERATION NOTE: Refer to FIGURE 4 for component locations. 1. Apply power to the oven. Program the time and temperature into the computer (1). The blower relay (2), belt stop relay (3) and heat relay (4) are energized. 1. 2. 3. 4. 5. 6. 7. 8. 9. 10. 11. 12. 13. 14. 15.
FIGURE 4 2---8 9 9 1 9 9 9 7 2 7 11 10 3 5 6 4 12 8 14 13 8 15 OPERATION
MT1828 MT1828G CE OVENS --- M6462 REV B COMPONENT REFERENCE 4. If the hi limit (9) is closed, power goes to the convection blower pressure switch (10). This switch closes when the convection blowers (11) are operating. If the switch is closed, power goes to the flame blower (12), the common terminal of the burner pressure switch (13) and terminal #7 of the latching relay (14). 5. If the burner pressure switch (13) is closed between COM and N.C., power goes to #4 and the coil of the latching relay (14).
FIGURE 5 2---10 23 23 1 23 23 7 22 6 2 24 8 3 4 5 18 9 11 20 10 17 11 13 16 12 19 21 15 14 OPERATION
MT1828 MT1828E CE OVENS --- M6453 REV A COMPONENT REFERENCE OPERATION NOTE: Refer to FIGURE 6 for component locations. 1. Apply power to the oven. Program the time and temperature into the computer (1). The blower relay (2), belt stop relay (3) and heat relay (4) are energized. 1. 2. 3. 4. 5. 6. 7. 8. 9. 10. 11. 12. 13. 14. 15.
FIGURE 6 2---12 8 8 1 8 8 8 7 2 7 10 9 3 5 6 4 11 15 13 12 15 14 OPERATION
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CHAPTER 3 CALIBRATION AND ADJUSTMENT
MT1828 CONVECTION BLOWER MOTORS TO CHECK MOTOR ROTATION TO CHECK LOW-LIMIT 1. Remove the back of the oven body and verify proper motor rotation. (See FIGURE 1) 1. Turn the oven on and let it heat up to approximately 200_F (93_C). For motor placement, the direction of rotation is viewed from the oven’s rear, working from left to right, beginning at the control box. In most cases, the motor direction is referenced to the end of the shaft (EOS).
CALIBRATION AND ADJUSTMENT REGULATED GAS PRESSURE Setting Equipment for Other Types of Gas -- CE Models 1. Let the oven run up to 510_F (266_C). Program the belt for 7 minutes. You may now verify the operational and regulated gas pressures. 1. Shut off the gas valve and turn off the operating switch. Incoming static gas pressure to the unit, with all the gas appliances drawing from the supply, should be a minimum of 5.5” W.C. (13.7 mbar) for natural gas and 11” W.C. (28 mbar) for propane gas.
MT1828 COMPUTER CONTROL CONFIGURATION INITIATING ACCESS MODE CONFIGURATION The Cooking Computer provides a special Access Mode for setting and displaying certain computer special functions. To initiate the Access Mode place the control in the OFF state, (OFF is shown in the display when power is first applied to the control). Press the following sequence of keys to set the control to Access Mode: CLEAR 1 2 3 4 5 6 ENTER. The display will show ACCESS.
CALIBRATION AND ADJUSTMENT Boost Option -- (versions 2.00 or 3.00) When the controller is in the “ACCESS” mode, press the following buttons: CLEAR 2 1 2 ENTER to enter the boost option. DISPLAY BOOST / MODE-? (Flash alternately) ACTION TAKEN Press PROG ENTER DISPLAY OPT-1 OPT-2 ACTION TAKEN or Press any numeric key to toggle between OPT-1 and OPT-2 Select OPT-1 to turn off boost mode.
MT1828 TEMPERATURE CALIBRATION TO ENTER THE CALIBRATION MODE 1. Press PROG/ENTER followed by ACT_TEMP. The display flashes either POS * OFFSET or NEG * OFFSET 1. Press the ON/OFF key until OFF is displayed. 2. Press CLEAR 1 2 3 4 5 6 ENTER to enter the access mode. The display reads ACCESS. NOTE: POS OFFSET is displayed if a value has been programmed in for a positive offset. NEG OFFSET is displayed if a value has been programmed for a negative offset.
CALIBRATION AND ADJUSTMENT BELT SPEED CALIBRATION CLOSED LOOP SYSTEM To enter the calibration mode: 3. ENTER ACTUAL TIME --- Place an object on the belt. Note the time from entrance to exit. Enter the actual measured time. 1. Press the ON/OFF key until OFF is displayed. 2. Press CLEAR 1 2 3 4 5 6 ENTER to enter the Access mode. The display reads ACCESS. 4. ENTER TEST TIME --- If the actual measured time is not within 5 seconds of the test time, repeat the belt verification test to obtain better accuracy.
MT1828 OPEN LOOP SYSTEM To enter the calibration mode: time spent on STEP---2, measure off 10” on the conveyor support. Place an object on the belt and note the travel time for the 10” measured distance. 1. Press the ON/OFF key until OFF is displayed. 2. Press CLEAR 1 2 3 4 5 6 ENTER to enter the Access mode. The display reads ACCESS. A.) The display reads STEP ---2 TIME ---?. Enter the measured travel time for STEP---2. Min: 0 Max: 59:59 (min:sec). Press the PROG/ ENTER key.
CALIBRATION AND ADJUSTMENT MOTOR CONTROL BOARD High/low speed motor control board adjustment for 180 and 130 volt DC motors COMPUTERIZED OVENS 130 Volt System NOTE: The motor control board is located on the slide out control panel. High Speed Motor Adjustment: For closed loop systems follow Belt Speed Verification through STEP 5 (see page 3---6). For open loop systems follow Belt Speed Calibration through STEP 2 (see page 3---7). 1.
MT1828 Minimum Speed Torque (current) limiting adjustment (DO NOT ADJUST) Maximum Speed Acceleration Adjustment Switches 2,4,5,6,7 ACC Yellow or Violet (pin 12) MAX Orange or Gray (pin 10) Blue Gray Violet TP2 Socket J1 Line Fuse ON DIP Switch on early models only TP1 Test Points Blue (pin 8) TORQ MIN REG Regulation Adjustment Armature Fuse FL TB1 Speed Pot L N A1 NOTE: Colors may vary between early ovens.
CHAPTER 4 ENHANCEMENTS
MT1828 BURNER NOTE: Refer to the new wiring diagram. NEW BURNER INSTALLATION 15. Install the new probes as follows: NOTE: Refer to FIGURE 1 for correct probe locations. 1. Disconnect the power to the oven. Shut off the main gas valve to the oven. 2. Disconnect the incoming gas line to the oven. 3. Remove the two screws securing the control box cover. Remove the control box cover. 4. Some ovens have a lower panel below the control box cover containing two fuses. If so, remove this panel.
ENHANCEMENTS 20. 21. 22. 23. 24. 25. 26. 28. Replace any existing schematic diagrams with the new ones provided. Schematics are provided for both integral control and remote control ovens. Be sure to use only those appropriate for the oven being upgraded. Discard the inapplicable schematics. 29. Install the new chain guard onto the chain guard bracket using the #10 pan had screws, washers and lockwashers provided.
MT1828 Reuse Gas Valve Assembly Gas Stack Union Chain Guard Bracket Burner Assembly FIGURE 2 Mount to chain guard bracket here Mount to floor of control box here FIGURE 4 FIGURE 3 4---3
ENHANCEMENTS IGNITER AND FLAME RODS FIGURE 5 illustrates the correct location of the igniter and flame rod. Gap .109 (7/64) from center of hole to edge of probe Gap .109 (7/64) from center of hole to edge of probe Both are fixed and should not move or swing.
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CHAPTER 5 TROUBLESHOOTING
MT1828 DC DRIVE SYSTEM POSSIBLE CAUSE(S) SUGGESTED REMEDY Symptom #1 --- Conveyor Belt will not run D Oven in OFF mode. D Turn to ON position. D Loose computer controller cord connection. D Adjust and retighten cables and set screws. D Time not programmed into computer. D D Emergency stop switch on OFF. D Pull switch out to ON. D Control circuit breaker tripped. D Reset breaker. D Belt hooked on something in oven. D Turn oven OFF, unhook and repair problem. D 5 amp line fuse blown.
TROUBLESHOOTING COMPUTER CONTROL SYSTEM POSSIBLE CAUSE(S) SUGGESTED REMEDY Symptom #1 --- Computer controller displays: PROBE - OPEN - PROBE - SHORT and alarm buzzer sounds D Internal problem with computer controller. D D Loose connections at computer controller. D D Shorted or open RTD probe. D Verify display integ. in the 2nd level programming. If the controller has been programmed the computer may need to be replaced. Tighten connections.
MT1828 HEATING SYSTEM POSSIBLE CAUSE(S) SUGGESTED REMEDY Symptom #1 --- Burner will not fire D Oven in OFF mode. D Turn to ON position. D Emergency stop switch on OFF. D Pull switch out to ON. D Control circuit breaker tripped. D Reset breaker. D Combustion motor not running. D D D D D D Main Temperature Controller not set above ambient temperature. Manual gas valve closed. Intermittent Ignition Device (IID) system locked out. Check transformer for primary and secondary voltage.
TROUBLESHOOTING POSSIBLE CAUSE(S) SUGGESTED REMEDY Symptom #2 --- Oven will not reach desired temperature D Gas pressure to oven is too low. D Contact local gas representatives. D Top air plates missing. D Install air plates. D Faulty RTD probe. D D Blower motor(s) running backward. D D Controller out of calibration. D D Excessive food/debris accumulation blocking the airflow. D Use the chart in the Technical Appendix (page NO TAG) to determine if probe is bad. Replace if necessary.
MT1828 CONVECTION SYSTEM POSSIBLE CAUSE(S) SUGGESTED REMEDY Symptom #1 --- Blower motor(s) not running D Oven in OFF mode. D Press ON/OFF key. D Remote emergency stop switch on OFF. D Pull switch out to ON. D No power to oven. D D Motor circuit breaker tripped. D Replace fuse. Determine amp draw. D Faulty start capacitor. D Replace capacitor. D Motor(s) burnt out. D D Motor contactor open. D D Thermal overload tripped. D Verify power to motor(s).
TROUBLESHOOTING POSSIBLE CAUSE(S) SUGGESTED REMEDY Symptom #36 --- Blower motor running backward D D Motor off by thermal overload (other fans forcing blower to spin). Faulty capacitor. D D Determine if the cooling blower (or fans) are operating. If not, verify voltage to the cooling blower. If voltage is present, replace the cooling blower motor. If voltage is not present, verify voltage through the thermal switch. If no voltage is present, replace the thermal switch. Replace capacitor.
