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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 ELE
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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 co
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SECTION 3: COMPONENT ACCESS OF FUNCTIONAL COMPONENTS..................................16 DOOR GASKET REPLACEMENT............................................................................................................................ 17 TO REMOVE DOORS FROM THE OVEN................................................................................................................ 18 INSTALLATION OF OVEN DOORS .....................................................................................
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GAS CONVECTION OVEN "GAS SPECIFICATIONS” MAIN PILOT GAS TOTAL BURNER ORIFICE PILOT ORIFICE PRES. W/C B.T.U.'S ORIFICE AMT. ORIFICE AMT. NAT PRO * NAT PRO NAT PRO ** 4.5" 5 40,000 / ” #55 2 .020" .012" 1 10.0" MCO 64 (.0781”) 5.0” 4.5" 5 60,000 / ” #55 3 .020" .012" 1 10.0" MCO 64 (.0781”) 5.1” 4.5" 5 80,000 / ” #55 4 .020" .012" 1 10.0" MCO 64 (.0781”) 5.5” * - Gas pressure measured at burner manifold. ** - Gas
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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.) HIG
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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
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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 i
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ELECTRONIC CONTROLS - “E” Sequence of Operation (With the Oven Doors Closed) COOK HIGH 1. Line Voltage is supplied to the Mode Switch, Door Switch and the Momentary Light HEAT O F Switch. F COOL LOW 2. Set Mode Switch to COOK and close the oven doors. Line Voltage is sent from Mode DOWN 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. Set desired temperature. The controller’s
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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- 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. -F2- Over temperature alarm. If this failure code appears in the
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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. 240V 208V 120V NEUTRAL E5 E4 E3 E2 E9 AUX GROUND E1 E10 - + - + E11 BAKE E6 E12 PROBE START CANCEL TIMER TIMER E7 DOOR E8 REAR VIEW FR
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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 th
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Entry Exit UPO - User Preference Offset. Used by the user to adjust the controlling temperature +/- 50º in 1º increments. 1. Set the time digits to 00:00. 1. Depress the 2. Set the temperature digits to X10º. Actual Temp 3. Depress & hold the Start button for five seconds. button to lock-in. 4. “UPO” & Current UPO will be displayed. Turn TEMP or TIME dial to adjust. TO CHANGE FAHRENHEIT TO CELSIUS (and vise versa) 1. Set the time digits to 00:00. 1. Depress the 2. Set t
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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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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 with the startup and checkout procedure. TURN GAS SUPPLY OFF. TURN THERMOSTAT NO Check line voltage power, low voltage transformer, limit controller, thermostat (CONTR
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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 wi
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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 LAZY YELLOW FLAME Check for lack of air from: • Large orifice • Dirty lint screen, if used • Dirty primary air opening, if there is one • Pilot adjustment at minimum WAVING BLUE FLAME Check for : • Excessive draft at pilot locations • Recirculating products of combustion NOISY LIFTING BLO
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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
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2. Locate stainless 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. 1 2 FILE NAME JIT03418 2 3 To Remove Doors from the Oven 1. Remove top front cap veneer. 18
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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 3 JIT03459 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
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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 to the door liner
