Garland MCO-GD-10E User's Manual
Contents
1. 7 REAR GAS INLET p a L s 1 716 813mm 37mm 2 38 x 5 n b 3 4 N P T 60mm x 127mm 19mm 813mm 1 2 L P FI GAS INLET n 43 1 4 DEEP 54 9 16 1099mm DEEP amp 70 1 2 Fe 1461mm r r 1386mm 39 1 45 0 Prema 1791mm 997mm STD 3 mm 2 po 1813 38 RUN 35 9 16 648 813mm 903mm Uu 17 3 4 19 451mm Z gt 483mm 38 E 165mm N 65m Lo FE t r Single Deck Front View Top View Double Deck Front View Model Ww W H wlg D Lb KG Cu Ft MCO GS 10 MCO GS 20 610mm 24 610mm MCO GD 10 610mm 28 711mm MCO GD 20 29 36mm 24 610mm 28 711mm 965mm INPUT CHART Natural or Propane Gas ELECTRICAL CHARACTERISTICS Model KW BTU HR Fo amas 120V 1 Phase 240V 1 Phase mm Ye HP One E 9 NPT Y HP SECTION 2 OVERVIEW OF OPERATIONAL SEQUENCES Understanding the sequence of operation is necessary in properly trouble shooting this appliance In this section the sequence of operation will be covered first as well as calibration and operation of components and ba2. 9 USER PREFERENCE OFFSET FOR THE ELECTRONIC 10 GOM6000 DPO EE 11 ier rea occ EI 11 ELECTRONIC PILOT amp MAIN BURNER IGNITION SEQUENCE u u u nacer nr 12 FIRST STAGE TRIAL FOR PILOT 12 SECOND STAGE MAIN BURNER OPERATION enn 12 SAFETY LOCKOUT TIME tete iie teet A 12 SERVICE E 13 PRELIMINAR Y CHE O etd ete pete tee Peter 13 SYSTEM TROUBLE SHOOTING icit cec tte rait dtt 13 S86 CHECKOUT AND TROUBLE SHOOTING 14 CHECK SPARK IGNITION CIRCUIT 15 CONTROL MODULE FLAME SENSOR 15 SECTION 3 COMPONENT ACCESS OF FUNCTIONAL COMPONENTS 16 DOOR GASKET REPLACEMENT eereeeeeenee eene nnne eee ea 17 TO REMOVE DOORS FROM THE U u u uuu uuu uuu uuu 18 INSTALLATION OF OVEN DOORS omic 19 INSTALLING AND ADJUSTMENT OF THE DOOR CHAIN I U u u uu uuu u 19 DISASSEMBLY OF THE LE
3. CONTROLLER CALLS STAGE 1 SPARK GENERATOR POWERED TRIAL FOR First valve pilot operator opens IGNITION PILOT BURNER OPERATION Pilot burner lights OR Pilot burner does not light Module senses flame After 90 second system current locks out must be manually reset Shutoff lockout timing is stamped on module MU EGER FLAME CURRENT SENSED Spark generator off POWER INTERRUPTION OPERATION System shuts off restarts Second valve operation main opens y to when power is restored MAIN BURNER OPERATION PILOT FLAME FAILURE Module monitors pilot flame current Main valve closed Module starts trial for ignition THERMOSTAT CONTROLLER SATISFIED END Valves close pilot and main burners are off SERVICE PRELIMINARY CHECK The following visual checks should be made before trouble shooting and after installation or maintenance 1 Check power to appliance and S86 2 Manual shutoff cocks in gas line to appliance must be open 3 Make certain all wiring connections are clean and tight 4 First de energize the system and wait at least one 1 minute This resets the module allowing a return to start condition Then energize the system 5 Review the S86 system normal sequence of operation SYSTEM TROUBLE SHOOTING Start the system by setting the thermostat or controller above required temperature Observe system response Establish type of malfunction or deviation from normal operation Use the
4. S86 Intermittent Pilot System Trouble Shooting Table to check for normal system operation Use table by following instruction questions in box If the condition is true or okay answer yes go down to next box underneath If the condition is not true or not okay answer no go right to the next box alongside Continue checking 13 and answering conditions in each box encountered until a problem and or the repair is explained After any maintenance or repair the trouble shooting sequence should be repeated until the trouble shooting procedure ends with a normal system operation START NOTE Before troubleshooting familiarize yourself ith the startup and checkout procedure TURN GAS SUPPLY OFF TURN THERMOSTAT CONTROLLER TO CALL Check line voltage power low voltage transformer limit controller thermostat FOR HEAT controller and wiring O MODU AV NOMINAL Pull ignition lead and heck spark at module SPARK ACROSS IGNITOR SENSOR GAP YES POWER On models with vent damper plug make sure vent damper had not been installed then remove Replace vent damper if necessary On other models replace module Check ignition cable ground wiring ceramic insulator and gap and correct Check boot of the ignition cable for signs of melting or buckling Take protective action to shield cable and boot from excessive temperature Check that all manual gas valves are open supply tubing and pressure are g
5. be steady If the reading is below the value designated or the reading is unsteady check the pilot flame and electrical connections as described above Also replace the ignitor sensor if the ceramic insulator is cracked EXAMPLES OF UNSATISFACTORY PILOT FLAMES 15 APPEARANCE CAUSE SMALL BLUE FLAME Check for lack of gas from e Clogged orifice filter e Clogged pilot filter e Low gas supply pressure e Pilot adjustment at minimum LAZY YELLOW FLAME Check for lack of air from e Large orifice e Dirty lint screen if used e Dirty primary air opening if there is one e Pilot adjustment at minimum Check for e Excessive draft at pilot locations e Recirculating products of combustion Check for e High gas pressure HARD SHARP FLAME This flame is characteristic of manufactured gas Check for e High gas pressure e Orifice too small SECTION 3 ACCESS OF FUNCTIONAL COMPONENTS 16 This section will give you the best way to access component for replacement COMPONENT LOCATIONS Top Front Center Door Chain Door Catch Right Front Control Panel 24v Transformer Ignition module Redundant gas valve Lower Front Door Micro Switch Data Plate Burner Package Inside Oven Oven Convection Motor Oven Interior Lights Door Gasket Replacement 1 Open oven doors 17 Single Deck Front View 2 Locate stai
6. cycle together To cancel depress the Cancel Timer key on the control This controller will remain in this COOK n HOLD program until removed see User Preference Programming in the following pages OPERATION OF THE PULSE FUNCTION When Pulse Program has been entered in the controller the AUX relay will open for 30 seconds and close for 30 seconds The 30 seconds open amp closed is a factory preset time and cannot be altered in the field The controller will remain in this Pulse Program until removed see User Preference Programming in the following pages USER PREFERENCE OFFSET FOR THE ELECTRONIC CONTROLLERS 10 The User Preference Offset is designed to enable the user to adjust the controlling temperature There are two different styles of controllers used by GARLAND at the present time They are the Robertshaw COM6000 and COM6700 Series To determine which of the controllers you are working on look at the back of the controller and you will see a sticker with a printed number like 100 289 03 below this number is the controller style number For example COMA 6704 GL This indicates that controller is in the COM6700 Series Or if the number was 6000 GA it would indicate that it is a COM 6000 COM6000 UPO MODE UPO User Preference Offset Used by the user to adjust the controlling temperature 50 in 1 increments Set the time digits to 00 00 Depress the Set the temperature digits to X10 Can
7. is enabled when not cooking If this failure code appears in the display the cook relay may be on even if the control is not cooking The control should be replaced Over temperature alarm If this failure code appears in the display the control is sensing an oven temperature 50 or more above the maximum set temperature 5009 This failure may be caused by a faulty sensor Check the sensor connection for loose wires Replace the sensor and check for proper operation If failure continues replace the control Open sensor circuit If this failure appears in the display the control is sensing an open circuit at the sensor input This failure is most often caused by a poor connection or broken sensor Check sensor connection and leads for broken wires of loose connections Replace sensor and check for proper operation If failure continues replace control Shorted sensor circuit If this failure appears in the display the control is sensing a short circuit at the sensor input This failure is most often caused by loose wires at the connection of shorted sensor leads Check sensor connection and leads for loose wires Replace sensor and check for proper operation If failure continues replace control Relay outputs not enabled when cooking If this failure appears in the display the control cannot turn the relays on even when cooking The control should be replaced No 60 Hz input The control does not sense the input power This failure mode
8. is most often the result of a failed component in the control However this failure may also be the result of a very noisy power line Look for any large electrical noise producing machinery such as mixers compressors dishwashers etc If possible turn these machines off Reapply power to the oven If the failure repeats replace the control If the failure does not repeat an electronic control may not work in this application because of noise You must isolate the supply circuit The control has detected that calculated EEPROM check sum is not the same as the expected check sum retrieved from the EEPROM When the control detects this error code it will disable outputs before the alarm sounds RESISTANCE vs TEMPERATURE CHART FOR INTERNAL OVEN TEMPERATURE SENSOR The chart below will provide the Ohms at various temperatures This will enable you to determine if the temperature probe is operable The chart is in Degrees Fahrenheit How to use chart for 350 read down to 300 then across to 50 answer is 1654Ohms of resistance 0 932 953 974 995 1016 1038 1059 1080 1101 1122 100 1143 1163 1184 1205 1226 1247 1267 1288 1309 1329 200 1350 1370 1391 1411 1432 1452 1472 1493 1513 1533 300 1553 1574 1594 1614 1634 1654 1674 1694 1714 1733 500 1949 1969 1988 2008 2027 2046 2065 2085 2104 2123 ROBERTSHAW COM600
9. 0 CONTROLLER The controller needs voltage to operate and is capable of operating on three 3 different line voltages 115 Vac 208 Vac 240 Vac On the back of the Robertshaw COM6000 there are several 1 4 male spade terminal or pin connections The below is a drawing of the rear of a Robertshaw COM6000 Controller along with a definition of each of the pin connections 240V 208V 120V NEUTRAL GROUND PROBE REAR VIEW FRONT VIEW OPERATION OF THE TEMPERATURE FUNCTION When the controller is powered up the LED will be illuminated To enter a cook temperature rotate the right dial The digits will go up as you rotate the dial to the right and decrease if rotated to the left The controller determines if the oven is at set temperature by the RTD sensing probe If the controller senses that the oven is below the displayed set temperature the controller activates the bake relay calling for heat At the same time the temperature digits begin to blink indicating that the controller is calling for heat Once the controllers set temperature is satisfied the temperature digits will stop flashing and remain constant and deactivating the bake relay NOTE The temperature digits will remain constant unless the set temperature is altered If altered the digits will again blink until the new set temperature is reached The controller will hold a tolerance of 5 To access the actual oven temperature depress the start key for three 3 seconds a
10. FT DOOR 2 kunde 19 DISASSEMBLY OF THE RIGHT DOOR W O WINDOW rana 20 TO REPLACE OR ADJUST DOOR LATCH MECHANISM u 22 TO REPLACE CONVECTION OVEN MOTOR ASSENBLY u u uu uuu u 22 CONVECTION OVEN MOTOR ASSEMBLY U 23 MAIN BURNER PILOT BURNER amp DOOR MICRO SWITCH LOCATION 24 SECTION 4 COMMON WIRE DIAGRANS S J J 25 SECTION 1 SPECIFICATION amp DIMENSIONS 3 GAS CONVECTION OVEN GAS SPECIFICATIONS MAIN PILOT GAS BURNER ORIFICE PILOT ORIFICE PRES W C ORIFICE AMT ORIFICE AMT NAT PRO pro 0781 Pro a TER 0781 es 0781 Gas pressure measured at burner manifold Gas pressure measured at redundant gas valve pressure tap All models single deck ovens amperage rating is 6 2 each oven Manifold size is 34 N P T National Pipe Thread NOTE Two speed motor 1140 and 1725 R P M 60 Hz clock wise motor rotation looking into oven cavity NOTE Each deck supplied with a 6 ft power supply cord for 120 volt units DIMENSIONS amp SPECIFICATIONS 1 12 38mm 7 1 1 2 1 2 138mm 7 13mm Zu 1 78 7 34 GAS INLET F 48mm 197mm
11. GARLAND A WELBILT COMPANY BUILT TO LEAD BUILT TO LAST SERVICE MANUAL THE MASTER GAS CONVECTION OVENS Models covered in this manual are MCO GS 10M MASTER CONVECTION Oven GAS STANDARD DEPTH 10 SINGLE DECK Manual CONTROL MCO GS 10E MASTER CONVECTION OVEN GAS STANDARD DEPTH 10 Single DECK ELECTRONIC CONTROL MCO GD 10M MASTER CONVECTION Oven GAS DEEP DEPTH 10 SINGLE DECK Manual CONTROL MCO GD 10E MASTER CONVECTION Oven GAS DEEP DEPTH 10 SINGLE DECK ELECTRONIC CONTROL GARLAND Commercial Industries Inc 185 East South Street Freeland Pennsylvania 18224 DIRECT ON SITE SERVICE 1 800 451 1165 GENERAL INFORMATION 1 800 424 2411 FORM GCI MCOVN PRINTED IN THE U S A This service manual is designed to answer questions related to model operational requirements troubleshooting and disassembly assembly procedures It contains electronic ignition operation trouble shooting and electronic control operations that include diagnostic codes ladder diagrams wire diagrams and troubleshooting It also includes BTU ratings orifice size and gas pressure technical data for each model For example if you need to know information on manual controls manual controls controls the oven with hydraulic thermostat electric mechanical timer refer to SECTION 2 OVERVIEW OF OPERATIONAL SEQUENCES Sequence of Operation This book is broken down into sections each section will list the applicable
12. OTES ELECTRONIC CONTROLS E Sequence of Operation With the Oven Doors Closed 1 Line Voltage is supplied to the Mode Switch Door Switch and the Momentary Light Switch Set Mode Switch to COOK and close the oven doors Line Voltage is sent from Mode Switch to power up the Controller and to the AUX relay on the controller With the oven doors closed Line Voltage is sent to the 24 volt transformer Set desired temperature The controller s relays now close The AUX relay sends Line Voltage to the motor relay coil closing the circuit to the Hi Lo Fan Switch The motor now operational causes the centrifugal switch to close and send the Neutral Voltage to the 24 Volt Transformer G2 Temp 0 12 HOUR 140 500F The bake relay completes the circuit from the 24 volt transformer to the ignition module and ignition occurs heating the oven Below is a simplified power diagram 24 Volt Motor Transformer Centrifuqal Switch Thermostat Door Sw Ign Module Hi Speed Motor Relay Lo Speed Neutral AUX Mode Sw COM6000 Light Sw ELECTRONIC CONTROL FAILURE CODES The GARLAND digital control has a self diagnostic program If a problem occurs within the digital controller you may see one of the codes Below is a listing of the codes with explanations F1 F2 F3 F4 F5 F6 F7 Relay output
13. OWN To disassemble left door 1 Once the door has been removed from the oven refer to instructions on the previous page remove the 12 truss head 10 x Y Phillips screws O 2 Remove 2 allen head cap screws from the door handle amp Carefully pry off the door panel from the door window bezel Remove 2 hex head m s 1 4 20 x from the door liner that attach hold down straps O to the door liner Lift out the door frame Carefully pry off the door window for door liner To remove door catch remove 2 pan head Phillips screws To reassemble reverse above procedure ONDU NOTE There is a seam one side of the bezel that is part of the door window reinstall working from the opposite side that the seam is on and work around the window towards that seam Disassembly of the Right Door w o window 20 NOTICE DEPENDENT RIGHT HAND DOOR SHOWN M Y 1 1 lt MC 2 A bu b N 3 y RN Sed 4 SoH 1 Once the door has been removed from the oven refer to instructions on page 19 remove 9 truss head s m s 10 x Y from the top bottom and left side as shown from the door panel 2 Pry the door liner apart from the door panel This will expose the door frame 3 To reassemble reverse above procedure 21 To R
14. cel button to Depress both the Start and Cancel buttons for five seconds lock in TO CHANGE FAHRENHEIT TO CELSIUS and vise versa Set the time digits to 00 00 Depress the Set the temperature digits to X20 Cancel button to Depress both the Start and Cancel buttons for five seconds lock in Rotate either dial to display FFF or CCC in the temperature display TIMER RESOLUTION CHANGING Set the time digits to 00 00 Depress the Set the cook temp to X30 Cancel button to Depress both the Start and Cancel buttons for five seconds lock in Rotate either dial to display HR or MN CHANGE THE HERTZ Set the time digits to 00 00 Depress the Set the cook temp to X40 Cancel button to Depress both the Start and Cancel buttons for five seconds lock in Rotate either dial to display 50 or 60 Hz Set the time digits to 00 00 Depress the Set the cook temp to X50 Cancel button to Depress both the Start and Cancel buttons for five seconds lock in The word hold will now be displayed in the time display Rotate either dial to set hold temperature Set the time digits to 00 00 and temperature digits to 000 Depress the Depress both the Start and Cancel buttons Cancel button to Rotate either dial to display con for continuous operation or cyc for cycling lock in fan on amp off COM6700 UPO MODE 11 UPO User Preference Offset Used by the user to adjust the controlling t
15. ding they can be proven accurate Regardless of the type instrument used it is most desirable to double check it just before making an oven temperature check This can be done simply and quickly by placing the thermocouple tip or immersing the entire mercury thermometer in boiling water Note Mercury oven thermometers should be the total immersion type The resulting reading should be within several degrees of 212 depending on the altitude Generally a mercury thermometer can drop in excess of 25 when the doors are opened to check oven tem perature This condition makes it extremely difficult to get a true temperature reading Almost all ranges today have oven burners which cycle on and off The high and low points of the resulting temperature swing differential in the oven must be measured and averaged to determine the true operating temperature A thermocouple type test instrument is best suited to measure these temperature changes quickly and accurately and without opening the oven door With an accurate thermocouple test instrument or mercury thermometer it is still difficult to measure these changing oven temperatures and then average them correctly This is why we recommend that the thermocouple tip or the bulb of the thermometer be weighted Weighting adding mass to the test instrument compensates for oven temperature changes by making the test instrument less sensitive to these constant changes in temperature Note How thi
16. emperature 50 in 1 increments Set the time digits to 00 00 2 Depress the Set the temperature digits to X10 Actual Temp Depress amp hold the Start button for five seconds button to lock in UPO amp Current UPO will be displayed Turn TEMP or TIME dial to adjust TO CHANGE FAHRENHEIT TO CELSIUS and vise versa Set the time digits to 00 00 Depress the Set the temperature digits to X20 Actual Temp Depress amp hold the Start button for five seconds button to lock in Rotate either dial to display FFF or CCC in the temperature display TIMER RESOLUTION CHANGING Set the time digits to 00 00 Depress the Set the cook temp to X30 Actual Temp Depress amp hold the Start button for five seconds button to lock in Rotate either dial to display HR or MN CHANGE THE HERTZ Set the time digits to 00 00 Depress the a Set the cook temp to X40 Cancel button to Depress amp hold the Start button for five seconds lock in 1 Rotate either dial to display 50 or 60 Hz CHAIN PROGRAMMING 1 Press Pgm Mode on off A Press Pgm Select Pgm 1 5 Mode on off to Enter Event 1 parameters time temp fan speed etc Press Event key to exit program chain 2 event mode Enter Event 2 parameters Continue procedure up to six events FIRST STAGE TRIAL FOR PILOT IGNITION On every call for heat system start the S86 performs an internal safe start check shows that a flame simulating c
17. eplace or Adjust Door Latch Mechanism Open doors and remove all oven racks Open oven doors Remove 2 pan head Phillips screws Lift door latch mechanism up and out of door assembly To adjust latch mechanism loosen lock nut 8 and adjust by tightening or loosening adjustment nut To Replace Convection Oven Motor Assembly Drawing Below Remove 4 10 sheet metal screws that secure air baffle and remove air baffle Remove six hex nut 1 4 20 7 16 2A and lock washers gt 4A from motor mounting studs Place a piece of cardboard on oven floor to protect from scratching or chipping Pull entire motor assembly 1A away from rear oven wall into oven cavity and place on cardboard Disconnect wiring be sure to note wire locations To reinstall reverse above procedure Ex 47 FILE NAME JIT00024 Convection Oven Motor 22 2j Assembly FILE NAME JIT00012 1 Assemble Y motor mount plate insulation motor mount plate inner together by fastening four flat head m s 1 4 20x217 into the four holes noted on the above drawings 2 Secure each flat head m s 1 4 20x27 with a flat washer and three hex nuts 1 4 20 3 Attach motor mounting plate to motor Insert the four flat head m s 1 4 20 2 amp through the mounting tabs on motor as shown Secure with two hex nuts 1 4 20 4 Insert shaft of motor
18. nd the temperature will now display the actual oven temperature OPERATION OF THE TIMER FUNCTION To enter a desired cook time rotate the left time dial The digits will display in the first hour minutes amp seconds Above the first hour the timer will display in hours amp minutes The diplay will continue to blink until the START TIMER key is depressed The resolution of the timer can be altered to display only hours and minutes if desired see User Preference Programming in the following pages At the end of the timed period an alarm will sound until operator depresses the Cancel Timer key The timer in standard mode has no effect on the bake relay OPERATION OF THE COOK n HOLD FUNCTION When the controller has a HOLD temperature programmed the controller operates a little differently As noted earlier set cook temperature and time When the timer counts down to 00 00 the alarm will sound for five 5 seconds and the word HOLD will now be displayed in the time side of the LED display The AUX relay will also be deactivated at this time and stop the oven fan At the same time the cook temperature will change to the new hold temperature that was preprogrammed in the controller This new temperature will now blink indicating that a new set temperature must be reached Once this new set temperature is reached the digit will go constant After reaching the new set temperature the AUX relay oven fan and Bake relay heat will
19. nless steel door gasket mounted to oven front frame 3 Remove the 10 Phillips sheet metal screw that attach the retainer to the oven s front frame 4 Remove stainless steel door gasket 5 Replace stainless steel door gasket and to reverse above procedure to re install N N N FILE NAME N Dems JITO3418 2 To Remove Doors from the Oven 1 Remove top front cap veneer 18 2 Remove door chain assembly NOTE The A model does not come equipped with door chain Remove flat head metal screw 1 4 20 1 2 from bearing retainer Push the door toward hinge and lift up NOTE Bottom bearing retainer will stay in place Remove the right door in the same manner Que A m i FILE NAME en WR Ry u ER JIT03459 ER D MA 4 p wA To Reinstall Doors onto Convection Oven 1 Reverse procedure above 2 Close doors 3 Reinstall the door chain Installing and Adjusting Door Chain 4 Make sure two links are between sprocket and door rod and there should be 8 regular links plus one master link on the forward side of each chain 5 Tighten up turn buckles the right door should close approximately 1 2 before the left door 6 Secure the turnbuckles by tightening Locking 5 lock nuts S Door Stop BoltS T rnbuckles Disassembly of the Left Door 19 ZN _s NOTICE DEPENDENT DOOR SH
20. ondition is present During a normal start the S86 opens the pilot valve in the gas control This allows gas to flow to the pilot burner Simultaneously the electronic spark generator in the S86 produces a 15 000 volt spark pulse output This voltage produces a spark at the pilot burner ignitor sensor rod igniting the gas flowing around the electrode If the pilot flame is not detected during the trial for pilot ignition the S86H contains a safety lockout timer 90 Seconds to limit the trial for pilot ignition period SECOND STAGE MAIN BURNER OPERATION When the pilot flame is established a flame rectification circuit is completed to the burner ground The S86 flame sensing circuit detects the flame current and shuts the spark generator off At the same time the second operator main gas valve is opened in the gas control allowing gas flow to the main burners The pilot flame ignites the main burner conventionally SAFETY LOCKOUT TIME 12 The safety lockout timer circuit starts timing the moment the trial for pilot ignition starts When the timing period runs out the trial for ignition ends and the control module goes into lockout Before another attempt to start can be made the S86 must be reset Reset by adjusting the thermostat or controller or to its OFF position An alternate method is to shut the system power OFF If normal ignition does not occur use the trouble shooting table to determine the problem START THERMOSTAT
21. ood TURN GAS SUPPLY ON and pilot burner orifice is not blocked Check electrical connections between module and pilot operator on gas control PILOT BURNER LIGHTS Check for 24 Vac across PV MV PV terminals on module If voltage is okay replace gas control if not replace module NOTE If S8600B H S8610B H goes into lockout reset system For S8600M wait 6 minutes nominal for retry or reset system Check continuity of ignition cable to ground wire Clean flame rod Check electrical connection between flame rod and module Check for cracked ceramic flame rod insulator Check that pilot flame covers rod and is steady and blue Adjust pilot flame If problem persists replace module SPARK STOPS WHEN PILOT IS LIT Check for 24 Vac ac Check electrical con gas control or gas co NO MAIN BURNER LIGHTS YES NOTE If S8600B H wait 6 minutes nomin e Check continuity of ig NOTE If ground is p SYSTEM RUNS UNTIL CALL FOR HEAT LOSS If checks are okay rd OR HEAT ENDS WSHUISO CALL F No TROUBLESHOOTING ENDS S86 CHECKOUT AND TR CHECK GROUNDING A common ground is required for the pilot burner the ignitor sensor the GND terminal of the S86 and the main burner The main burner generally serves as the common ground If the ground is poor or erratic safety shutdowns may occur occasionally even though operation is normal at the time of the check
22. out Therefore if nuisance shutdowns have been reported be sure to check the grounding NOTE f the ground circuit path is incomplete the S86H system control will allow one trial for ignition before going into safety lockout Electrical grounding connections at the pilot burner ignitor sensor and S86 must be clean and tight If lead wire is damaged or deteriorated use only No 14 of 18 gauge moisture resistant thermoplastic insulated wire with 105 C 221 F minimum rating as replacement Excessive temperature at the ceramic flame rod insulator can also permit electrical leakage to ground Examine the flame rod and mounting bracket and correct if bent out of position Replace ignitor sensor of insulator is cracked CHECK SPARK IGNITION CIRCUIT The electronic module and step up transformer in the S86 provides spark ignition at 15 000 Volts open circuit This circuit can be checked at the S86 module as follows 1 Turn off the manual gas cock to prevent the flow of gas 2 Disconnect the ignition cable at the S86 stud terminal to isolate the circuit from the pilot burner ignitor sensor and prepare a short jumper lead using heavily insulated wire such as ignition cable 3 Energize the S86 Touch one end of the jumper firmly to the S86 ground terminal GND Do not disconnect the existing ground lead Move the free end slowly toward the stud terminal to establish a spark and then pull the lead wire slowly away from the stud Note
23. s weighting can be done is discussed later Measuring these changing high and low temperatures points in an oven is possible with either type of test device without weighting but is subject to possible inaccuracies This is most true at low temperature setting because in this area the function of time becomes a factor The simple averaging of temperatures then may not produce the true operating temperature Weighting provides the compensation for both time and temperature that is necessary We produced next page test curves showing actual results in the low temperature area showing the difference in results when using an unweighted and a weighted thermocouple or thermometer Tests were made with the same control same oven and dial at 170 mark not move d Chart No 1 Chart No 2 Unweighted Thermocouple dial setting 170 F Weighted Thermocouple Dial Setting 170F From the above it can be seen that an error of 15 is possible Chart 1 unweighted thermocouple indicates an erroneous average oven temperature of 185 Chart 2 weighted thermocouple indicates the average or true temperature to be 170 2 WEIGHTING A thermocouple can be weighted by clamping the tip between two one inch squares of 1 16 thick aluminum The thermocouple can also be weighted just as successfully by using a letter size sheet of aluminum foil Fold the foil 6 five times doubling the thickness with each fold After the fifth fold place the thermocouple
24. sic trouble shooting techniques for that specific model Follow each sequence carefully and get to understand its operation before moving on to trouble shooting MANUAL CONTROLS Sequence of Operation Starting with the oven doors in closed position E 1 Turn the Mode Switch to the Cook position This sends line voltage to the timer COOK power And with the doors closed line voltage is sent via the door switch to the thermostat A and the Hi Lo Fan switch 2 Select Hi or Lo speed the motor will now be operational 3 Rotate the temperature dial to desired temperature The thermostat will now call for heat sending line voltage to the 24 volt transformer With the motor operating the centrifugal switch is closed completing the neutral circuit to the transformer 4 The 24v transformer now sends 24 volts to the ignition module 5 The ignition sequence starts and oven temperature begins to rise See Ignition Sequence later in this manual Below is a simplified power diagram Hi Lo Sw Hi Speed Hi Lo Sw Door Sw Mode Sw Timer N Thermostat Neutral 24 Volt Motor Transformer Centrif Sw Line Light Sw Ign Module CALIBRATION OF THERMOSTAT INSTRUMENTATION A thermocouple type test instrument is preferred for measuring oven temperatures accurately Mercury thermometers are acceptable provi
25. the length of the gap at which arcing stops CAUTION Do not touch either stripped end of jumper or stud terminal This is a very high voltage circuit and electrical shock can result Perform the test immediately upon energizing the system before the S86H goes into safety lockout and interrupts the spark circuit 4 arc length of 1 8 3 2 mm or more indicates satisfactory voltage output Replace the S86 if no arc can be established or the maximum gap is less than 1 8 3 2 mm and the fuse and power to the S86 input terminal was okay CONTROL MODULE FLAME SENSOR CIRCUIT The control module provides AC power to the ignitor sensor which the pilot burner flame rectifies to direct current If the flame signal back to the control module is not at least 1 0 DC the system will lockout The output of the flame sensing circuit cannot be checked directly so check the flame sensing circuit indirectly by checking the flame sensing current from the ignitor sensor to the control module as follows 1 Connect a meter DC micrometer scale in series with the flame signal ground wire Burner Ground Terminal Disconnect the ground wire at the control module Connect the red positive lead of the meter to the free end of the ground wire Connect the black negative meter lead to the quick connect ground terminal on the control module 2 Restart the system and read the meter The flame sensor current must be at least 1 0 uA and the reading must
26. through the hub of the blower wheel Space the blower wheel 4 away from the inner motor mounting plate 5 Secure the blower wheel to the shaft of the motor by tightening the two set screws on the blower wheel hub Use a torque wrench and tighten to 180 inch pounds for proper securing For warranty replacement we require that you use the motor assembly Order motor assembly part CK1003090 2 Speed 115 Vac or CK1003091 2 Speed 208 240 Vac Export or Special CK1003092 1 Speed 115 208 240 Vac 23 Main Burner Pilot Burner Removal amp Door Micro Switch Location lt To access the Burners Pilot or Door Switch remove the lower combustion chamber not show This exposes these components also you will note that the rating or data plate is on the inside of the combustion shroud For ovens that are 80 000 B T U s there are four burners 60 000 B T U s there are three burners as shown in the above illustration and 40 000 B T U s there are two burners On 40 000 B T U models the pilot is located where the left or first burner usually is The two main burners are located in the center of the burner manifold By centering the burners it provides more uniform heating of the oven cavity 24 SECTION 4 COMMON WIRE DIAGRAMS 25 26 27 28
27. tip in the center of the aluminum piece and fold once more Finally fold in the sides so that the foil clings to the thermocouple tip A mercury thermometer can be weighted in much the same way by wrapping several layers of aluminum foil around the bulb end thus creating the necessary mass This procedure is a must if you open an oven door to check temperature THERMOSTAT OPERATION It is normal for a hydraulic thermostat cycling with a temperature swing of 45 to 50 When checking calibration first allow the thermostat to cycle a minimum of four 4 times second place your temperature sensor in the geometric center of the empty oven Once the oven has been allowed to preheat record the temperature at which the burners cycle ON and OFF Average the two readings that average should be 20 of the set point temperatu Example Thermostat set point at 300 first cycle Off at 325 Cycle back ON at 291 The average of 325 and 291 is 308 This thermostat is with the 20 to lerance If the thermostat is cycling beyond the 20 tolerance and the appliance is under warranty recalibrate the thermostat or if not under warranty consult owner for proper action If the thermostat is out of calibration more than fifty 50 it will not likely hold an attempt of recalibration we suggest that the thermostat be replaced lt B Dial Shaft Increase A Calibration Screw m Decrease 1 4 Tur CALIBRATION N
28. topics Use the Table of Contents to locate the topic and function that you are attempting to trouble shoot Table of Contents SECTION 1 SPECIFICATION amp DIMENSIONS sees 3 GAS CONVECTION OVEN GAS SPECIFICATIONS U u u u u u 4 DIMENSIONS amp SPECIFICATIONS uu 020022000200000000nnnnnnnnnnnnn nun nnnnannnnnnnnnnnnnnnannnnnnnnnnnnnnnnnnnnannnnnannnnnnnnnannennannnnnann 4 SECTION 2 OVERVIEW OF OPERATIONAL SEQUENCES cene 4 MANUAL CONTROLS MU e 5 Sequence Opera u m cei fag Ree ce de Fay Poet a a edu 5 Manual Ladder Diagram u u u een Reken 5 CALIBRATION OF THERM STAT aa uu uu u uu u T 5 Instrumentation s ernennen e ein hin 5 ba Ie E 6 REED 7 ELECTRONIC CONT ROUS E c 8 Sequence of Operation With the Oven Doors Closed 8 Electonic Ladder Wire DI89r8m _uu l a a pssqa a uay 8 ELECTRONIC CONTROL FAILURE CODES 9 CHART FOR INTERNAL OVEN TEMPERATURE SENSQOR u u u u u 9 ROBERTSHAW COM6000 CONTROLLER u u u u uu u u u u u u u u u
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