Garland MCO GD 10E User Manual

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.  
SECTION 3: COMPONENT ACCESS OF FUNCTIONAL COMPONENTS..................................16  
DOOR GASKET REPLACEMENT............................................................................................................................ 17  
TO REMOVE DOORS FROM THE OVEN................................................................................................................ 18  
INSTALLATION OF OVEN DOORS ......................................................................................................................... 19  
INSTALLING AND ADJUSTMENT OF THE DOOR CHAIN..................................................................................... 19  
DISASSEMBLY OF THE LEFT DOOR..................................................................................................................... 19  
DISASSEMBLY OF THE RIGHT DOOR (W/O WINDOW)....................................................................................... 20  
TO REPLACE OR ADJUST DOOR LATCH MECHANISM...................................................................................... 22  
TO REPLACE CONVECTION OVEN MOTOR ASSEMBLY.................................................................................... 22  
CONVECTION OVEN MOTOR ASSEMBLY............................................................................................................ 23  
MAIN BURNER, PILOT BURNER & DOOR MICRO-SWITCH LOCATION ............................................................ 24  
SECTION 4: COMMON WIRE DIAGRAMS .................................................................................25  
SECTION 1: SPECIFICATION & DIMENSIONS  
3
GAS CONVECTION OVEN "GAS SPECIFICATIONS”  
MAIN  
BURNER  
ORIFICE  
PILOT  
ORIFICE  
AMT.  
GAS  
PRES. W/C  
NAT PRO  
TOTAL  
B.T.U.'S  
ORIFICE  
AMT.  
PILOT  
ORIFICE  
*
NAT  
PRO  
NAT  
PRO  
**  
4.5"  
40,000  
60,000  
80,000  
5/64”  
#55  
2
3
4
.020" .012"  
.020" .012"  
.020" .012"  
1
1
1
10.0"  
10.0"  
10.0"  
MCO  
MCO  
MCO  
(.0781”)  
5.0”  
4.5"  
5/64”  
(.0781”)  
#55  
#55  
5.1”  
4.5"  
5/64”  
(.0781”)  
5.5”  
* - 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 ¾" 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 & SPECIFICATIONS  
1-1/2  
[38mm]  
1-1/2  
1/2 N.P.T.  
[13mm]  
[38mm]  
1-7/8  
7-3/4  
GAS INLET  
[48mm]  
[197mm]  
REAR GAS INLET  
32  
[813mm]  
32  
1-7/16  
[37mm]  
3/4 N.P.T.  
[19mm]  
2-3/8 x 5  
[813mm]  
[60mm x 127mm]  
FLUE  
GAS INLET  
43-1/4 DEEP  
57-1/2  
38-1/4  
54-9/16  
[1099mm] DEEP  
39-1/4 STD  
70-1/2  
[1461mm]  
[972mm]  
[1386mm]  
[1791mm]  
32  
[997mm] STD  
38  
[813mm]  
[965mm]  
35-9/16  
32  
25-1/2  
[903mm]  
[813mm]  
[648mm]  
19  
17-3/4  
[483mm]  
[451mm]  
6-1/2  
38  
[165mm]  
[965mm]  
38  
Single Deck  
(Front View)  
(Top View)  
[965mm]  
Double Deck  
(Front View)  
SHIP WEIGHT/DIM  
INTERIOR DIMENSIONS (per oven)  
EXTERIOR DIMENSIONS  
H (w/legs)  
Model #  
W
H
D
W
D
Lb./KG  
510/232  
1020/464  
510/232  
1020/464  
Cu. Ft.  
42 cu. ft.  
84 cu. ft.  
42 cu. ft.  
84 cu. ft.  
MCO-GS-10  
MCO-GS-20  
MCO-GD-10  
MCO-GD-20  
29”(736mm)  
29”(736mm)  
29”(736mm)  
29”(736mm)  
24”(610mm)  
24”(610mm)  
24”(610mm)  
24”(610mm)  
24”(610mm)  
24”(610mm)  
28”(711mm)  
28”(711mm)  
38”(965mm)  
38”(965mm)  
38”(965mm)  
38”(965mm)  
57½”(1460mm)  
70½”(1791mm)  
57½”(1460mm)  
70½”(1791mm)  
39”(991mm)  
39”(991mm)  
43”(1092mm)  
43”(1092mm)  
INPUT CHART - Natural or Propane Gas  
KW  
ELECTRICAL CHARACTERISTICS  
Model #  
BTU/HR  
60,000  
120,000  
60,000  
Equiv.  
17.6  
35.2  
17.6  
35.2  
Gas Inlet  
120V/1 Phase  
240V/1 Phase  
One @ 3.1 Amps  
Two @ 3.1 Amps  
One @ 3.1 Amps  
Two @ 3.1 Amps  
Motor  
½ HP  
½ HP  
½ HP  
½ HP  
MCO-GS-10  
MCO-GS-20  
MCO-GD-10  
MCO-GD-20  
One @ ¾” NPT  
One @1” NPT  
One @ ¾” NPT  
One @ 1” NPT  
One @ 6.2 Amps  
Two @ 6.2 Amps  
One @ 6.2 Amps  
Two @ 6.2 Amps  
120,000  
SECTION 2: OVERVIEW OF OPERATIONAL SEQUENCES  
4
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 basic 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 - "M"  
Sequence of Operation (Starting with the oven doors in closed position.)  
HIGH  
LOW  
COOK  
POWER  
ON  
1.  
Turn the Mode Switch to the “Cook” position. This sends line voltage to the timer.  
And with the doors closed, line voltage is sent via the door switch to the thermostat  
and the Hi/Lo Fan switch.  
O
F
F
COOL  
DOWN  
2.  
3.  
Select Hi or Lo speed, the motor will now be operational.  
TIMER  
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.  
5.  
The 24v transformer now sends 24 volts to the ignition module.  
The *ignition sequence starts and oven temperature begins to rise.  
*See “Ignition Sequence” later in this manual.  
TEMP  
Below is a simplified power diagram:  
Hi/Lo Sw.  
Hi/Lo Sw.  
Timer  
Hi Speed  
Lo Speed  
Door Sw. Mode Sw.  
Neutral  
Motor  
Centrif. Sw.  
24 Volt  
Transformer  
Line  
Thermostat  
Light Sw.  
Ign. Module  
CALIBRATION OF THERMOSTAT  
INSTRUMENTATION  
5
A thermocouple type test instrument is preferred for measuring oven temperatures accurately. Mercury thermometers  
are acceptable providing 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 this  
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  
260  
240  
220  
200  
180  
160  
140  
120  
100  
260  
240  
220  
200  
180  
160  
140  
120  
100  
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°.  
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 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 re.  
Example: Thermostat set point at 300°, first cycl e 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.  
"B" Dial Shaft  
"A" Calibration Screw Head  
Increase  
Decrease  
1/4" Turn  
- CALIBRATION NOTES -  
7
ELECTRONIC CONTROLS - “E”  
Sequence of Operation (With the Oven Doors Closed)  
COOK  
HIGH  
LOW  
1.  
2.  
Line Voltage is supplied to the Mode Switch, Door Switch and the Momentary Light  
Switch.  
HEAT  
O
F
F
COOL  
DOWN  
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.  
3.  
4.  
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.  
START  
TIMER  
CANCEL  
TIMER  
TIMER  
TEMP  
0-12 HOUR  
140-500F  
5.  
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  
Centrifugal Switch  
Transformer  
24 V  
Thermostat  
Ign. Module  
Door Sw.  
Hi Speed  
Lo Speed  
Motor Relay  
Neutral  
AUX  
Mode Sw.  
Light Sw.  
COM6000  
8
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 "F" codes.  
Below is a listing of the "F" codes with explanations:  
-F1-  
-F2-  
Relay output 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 (500°). 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.  
-F3-  
-F4-  
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.  
-F5-  
-F6-  
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 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.  
-F7-  
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.  
TEMP  
0°  
0°  
932  
10°  
953  
20°  
974  
30°  
995  
40°  
1016  
50°  
1038  
60°  
1059  
70°  
1080  
80°  
1101  
90°  
1122  
1329  
1533  
1733  
1930  
2123  
1143  
1350  
1553  
1753  
1949  
1163  
1370  
1574  
1773  
1969  
1184  
1391  
1594  
1793  
1988  
1205  
1411  
1614  
1813  
2008  
1226  
1432  
1634  
1832  
2027  
1247  
1452  
1654  
1852  
2046  
1267  
1472  
1674  
1871  
2065  
1288  
1493  
1694  
1981  
2085  
1309  
1513  
1714  
1911  
2104  
100°  
200°  
300°  
400°  
500°  
ROBERTSHAW COM6000 CONTROLLER  
9
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 ¼” 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.  
120V  
240V 208V  
NEUTRAL  
E5  
E4 E3  
E2  
E9  
AUX  
GROUND  
E1  
E10  
E11  
- +  
- +  
BAKE  
DOOR  
E6  
E7  
PROBE  
START  
TIMER  
CANCEL  
TIMER  
E12  
E8  
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 and 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 & seconds.  
Above the first hour, the timer will display in hours & 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 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 & 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 “PN: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 “COM-  
6000-GA” it would indicate that it is a COM 6000.  
COM6000 UPO MODE  
Entry  
Exit  
UPO - User Preference Offset. Used by the user to adjust the controlling temperature +/- 50º in 1º  
increments.  
1.  
2.  
3.  
Set the time digits to 00:00.  
Set the temperature digits to X10º.  
Depress both the Start and Cancel buttons for five seconds.  
1.  
Depress the  
Cancel button to  
lock-in  
TO CHANGE FAHRENHEIT TO CELSIUS (and vise versa)  
1.  
2.  
3.  
4.  
Set the time digits to 00:00.  
Set the temperature digits to X20º.  
Depress both the Start and Cancel buttons for five seconds.  
Rotate either dial to display FFF or CCC in the temperature display  
1.  
Depress the  
Cancel button to  
lock-in.  
TIMER RESOLUTION CHANGING  
1.  
2.  
3.  
4.  
Set the time digits to 00:00.  
Set the cook temp to X30º  
Depress both the Start and Cancel buttons for five seconds.  
Rotate either dial to display “HR” or “MN”.  
1.  
1.  
1.  
Depress the  
Cancel button to  
lock-in.  
CHANGE THE HERTZ  
1.  
2.  
3.  
4.  
Set the time digits to 00:00.  
Set the cook temp to X40º  
Depress both the Start and Cancel buttons for five seconds.  
Rotate either dial to display “50” or “60” Hz.  
Depress the  
Cancel button to  
lock-in.  
TO SET HOLD TEMPERATURE  
1.  
2.  
3.  
4.  
Set the time digits to 00:00.  
Set the cook temp to X50º  
Depress both the Start and Cancel buttons for five seconds.  
The word “hold” will now be displayed in the time display. Rotate either dial to  
set hold temperature.  
Depress the  
Cancel button to  
lock-in.  
TO SET OVEN INTO PULSE MODE  
1.  
Depress the  
Cancel button to  
lock-in.  
1.  
2.  
3.  
Set the time digits to 00:00 and temperature digits to 000°.  
Depress both the Start and Cancel buttons.  
Rotate either dial to display “con” for continuous operation or “cyc” for cycling  
fan on & off.  
COM6700 UPO MODE  
11  
Entry  
Exit  
UPO - User Preference Offset. Used by the user to adjust the controlling temperature +/- 50º in 1º  
increments.  
1.  
2.  
3.  
4.  
Set the time digits to 00:00.  
Set the temperature digits to X10º.  
Depress & hold the Start button for five seconds.  
“UPO” & Current UPO will be displayed. Turn TEMP or TIME dial to adjust.  
1.  
1.  
1.  
1.  
1.  
Depress the  
Actual Temp  
button to lock-in.  
TO CHANGE FAHRENHEIT TO CELSIUS (and vise versa)  
1.  
2.  
3.  
4.  
Set the time digits to 00:00.  
Set the temperature digits to X20º.  
Depress & hold the Start button for five seconds.  
Rotate either dial to display FFF or CCC in the temperature display  
Depress the  
Actual Temp  
button to lock-in.  
TIMER RESOLUTION CHANGING  
1.  
2.  
3.  
4.  
Set the time digits to 00:00.  
Set the cook temp to X30º  
Depress & hold the Start button for five seconds.  
Rotate either dial to display “HR” or “MN”.  
Depress the  
Actual Temp  
button to lock-in.  
CHANGE THE HERTZ  
1.  
2.  
3.  
4.  
Set the time digits to 00:00.  
Set the cook temp to X40º  
Depress & hold the Start button for five seconds.  
Rotate either dial to display “50” or “60” Hz.  
Depress the  
Cancel button to  
lock-in.  
CHAIN PROGRAMMING  
1.  
2.  
3.  
Press Pgm Mode on/off.  
Select Pgm # (1-5).  
Press Pgm  
Mode on/off to  
exit program  
mode.  
Enter Event 1 parameters (time, temp, fan speed etc.). Press Event # key to  
chain 2nd event.  
4.  
5.  
Enter Event 2 parameters.  
Continue procedure up to six events.  
ELECTRONIC PILOT & MAIN BURNER IGNITION SEQUENCE  
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  
condition 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.  
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THERMOSTAT (CONTROLLER) CALLS  
FOR HEAT  
START  
STAGE 1  
TRIAL FOR  
IGNITION  
2
3
SPARK GENERATOR POWERED  
First valve (pilot) operator opens  
PILOT BURNER OPERATION  
Pilot burner lights.  
OR  
Pilot burner does not light.  
After 90 seconda system  
locks out; must be manually  
reset.  
Module senses flame  
current.  
a Shutoff/lockout timing is stamped on module.  
STAGE 2  
MAIN BURNER  
OPERATION  
4
FLAME CURRENT SENSED  
Spark generator off.  
POWER INTERRUPTION  
System shuts off, restarts  
when power is restored.  
Second valve operation (main) opens.  
PILOT FLAME FAILURE  
Main valve closed.  
Module starts trial for ignition.  
5
MAIN BURNER OPERATION  
Module monitors pilot flame current.  
6
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 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  
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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.  
NOTE: Before troubleshooting, familiarize yourself  
with the startup and checkout procedure.  
START  
TURN GAS SUPPLY OFF.  
TURN THERMOSTAT  
(CONTROLLER) TO CALL  
FOR HEAT  
NO  
Check line voltage power, low voltage transformer, limit controller, thermostat  
(controller) and wiring.  
POWER TO MODULE (24v  
NOMINAL)  
Pull ignition lead and  
check spark at module.  
On models with vent damper plug, make sure vent  
damper had not been installed, then remove.  
Replace vent damper if necessary.  
YES  
NO  
SPARK ACROSS  
IGNITOR/SENSOR GAP  
NO  
Spark okay?  
On other models, replace module.  
YES  
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.  
YES  
Check that all manual gas valves are open, supply tubing and pressure are good,  
and pilot burner orifice is not blocked.  
Check electrical connections between module and pilot operator on gas control.  
Check for 24 Vac across PV-MV\PV terminals on module. If voltage is okay,  
replace gas control; if not, replace module.  
TURN GAS SUPPLY ON  
PILOT BURNER LIGHTS?  
NO  
YES  
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.  
SPARK STOPS WHEN  
PILOT IS LIT?  
NO  
YES  
If problem persists, replace module.  
Check for 24 Vac acr
Check electrical conn
gas control or gas co
MAIN BURNER  
LIGHTS?  
NO  
YES  
NOTE: If S8600B,H;
wait 6 minutes nomin
Check continuity of ig
NOTE: If ground is p
though operation is no
Check that pilot flame
If checks are okay, re
SYSTEM RUNS UNTIL  
NO  
CALL FOR HEAT  
LOSS?  
YES  
CALL FOR HEAT ENDS  
SYSTEM SHUTS OFF?  
NO  
YES  
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 checkout. Therefore, if nuisance  
shutdowns have been reported, be sure to check the grounding.  
NOTE: If 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 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. An 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 µA 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 µA, and the reading must  
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:  
Clogged orifice filter  
Clogged pilot filter  
Low gas supply pressure  
Pilot adjustment at minimum  
Check for lack of air from:  
LAZY YELLOW FLAME  
Large orifice  
Dirty lint screen, if used  
Dirty primary air opening, if there is one  
Pilot adjustment at minimum  
Check for :  
WAVING BLUE FLAME  
Excessive draft at pilot locations  
Recirculating products of combustion  
Check for:  
NOISY LIFTING BLOWING FLAME  
High gas pressure  
This flame is characteristic of manufactured gas  
Check for:  
HARD SHARP FLAME  
High gas pressure  
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  
Single Deck  
(Front View)  
Door Gasket Replacement  
1.  
Open oven doors  
17  
2.  
3.  
Locate stainless steel door gasket, mounted to oven front frame.  
Remove the #10 Phillips sheet metal screw that attach the retainer to the oven's front  
frame.  
4.  
5.  
Remove stainless steel door gasket.  
Replace stainless steel door gasket and to reverse above procedure to re-install.  
1
2
FILE NAME  
JIT03418  
2
3
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).  
3. Remove flat head metal screw 1/4”-20x1/2” from bearing retainer.  
4. Push the door toward hinge and lift up. NOTE: Bottom bearing retainer will stay in place.  
5. Remove the right door in the same manner.  
1
2
FILE NAME  
JIT03459  
3
4
To Reinstall Doors onto Convection Oven  
1. Reverse procedure above.  
2. Close doors.  
3. Reinstall the door chain.  
2 Links  
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.  
8 Links  
5. Tighten up turn buckles, the right  
door should close approximately ½”  
before the left door.  
Turnbuckles  
6. Secure the turnbuckles by tightening  
lock nuts.  
Locking Nuts  
Door Stop Bolt  
Disassembly of the Left Door  
19  
NOTICE: DEPENDENT DOOR SHOWN  
6
3
7
4
5
8
2
7
1
7
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 ½ Phillips screws  
2. Remove 2 allen head cap screws from the door handle  
3. Carefully pry off the door panel from the door window bezel  
4. Remove 2 hex head m.s. ¼ -20 x ½ from the door liner that attach hold down straps  
the door liner  
5. Lift out the door frame  
6. Carefully pry off the door window  
7. To remove door catch remove 2 pan head Phillips screws.  
.
.
.  
to  
.
.
for door liner  
.  
8. To reassemble - reverse above procedure.  
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.  
5
1
2
3
4
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 ½ from the top, bottom and left side (as shown) from the door panel  
.
2. Pry the door liner  
3. To reassemble, reverse above procedure.  
apart from the door panel  
. This will expose the door frame  
.  
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