Thermador Pro Grand PRD304EG User manual

Service Manual for Thermador Pro Grand Dual Fuel Ranges: PRD304EG, PRD364EDG, PRD364EDPG, PRD364ELG, PRD366EG, PRD366EPG, PRD484ECG, PRD484EEG, PRD486EDG, PRD486EDPG, PRD486ELG
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TABLE OF CONTENTS
1General .....................................................................................................5
1.1 Applicable Models......................................................................................... 5
1.2 Data Rating Plate.......................................................................................... 5
1.3 Wiring Diagram ............................................................................................. 5
1.4 Technical Documents to Read Prior to Servicing.......................................... 6
1.5 Recommended Tools and Supplies .............................................................. 6
1.6 Important Safety Information......................................................................... 6
1.6.1 Safety Symbols Used In This Manual .................................................... 6
1.6.2 Safety Precautions to Know Prior to Servicing....................................... 6
2Operation.................................................................................................. 9
2.1 Knobs and Controls....................................................................................... 9
2.1.1 Standard Burner Knob ........................................................................... 9
2.1.2 ExtraLow Burner Knob........................................................................... 9
2.1.3 Griddle Control Knob ............................................................................. 9
2.1.4 Grill Control Knob................................................................................. 10
2.1.5 Temperature Selector Knob................................................................. 10
2.1.6 Five-Position Oven Function Selector Knob......................................... 10
2.1.7 Six-Position Oven Function Selector Knob .......................................... 10
2.1.8 Oven Lamp Switch............................................................................... 11
2.2 LED Indicators............................................................................................. 11
2.3 Automatic Re-Ignition.................................................................................. 11
2.4 Operation During a Power Outage.............................................................. 11
2.5 Maintop Components and Burner Assembly............................................... 11
3Testing, Adjusting, Troubleshooting Burners and Ignition .............. 12
3.1 Before Testing............................................................................................. 12
3.2 Rangetop Burner Characteristics................................................................ 12
3.3 Rangetop Flame Characteristics................................................................. 13
3.4 Testing Rangetop Burner Ignition................................................................ 14
3.4.1 Testing Ignition for HI, Medium, and Low Settings............................... 14
3.4.2 Testing Ignition for XLO Setting........................................................... 14
3.5 Adjusting Grill Burner Flame with the Air Shutter........................................ 14
3.6 Adjusting Rangetop Burner Valves Manually.............................................. 15
3.6.1 Special Tools Needed.......................................................................... 15
3.6.2 Adjusting the Bypass Screws............................................................... 15
3.7 Troubleshooting Burner, Flame, Ignition, and Elements ............................. 16
3.7.1 Burner and Flame Diagnostics for Rangetop Burners.......................... 16
3.7.2 Ignition Diagnostics for Rangetop Burners........................................... 16
3.7.3 Element Diagnostics............................................................................ 18
3.7.3.1 Safety Practices for Element Diagnostics..................................... 18
3.7.3.2 Element Diagnostic Tips............................................................... 18
3.7.3.3 Element Cycle/Circuit Specification .............................................. 18
3.8 Fault Codes................................................................................................. 19
4Service and Repair ................................................................................ 21
4.1 Preparing the Range for Servicing .............................................................. 21
4.2 Accessing Components under the Maintop................................................. 21
4.2.1 Removing Knobs, Grates, Trim, Burner Assemblies............................ 21
4.2.2 Removing Spill Trays........................................................................... 23
4.2.3 Removing Heat Shields ....................................................................... 23
4.2.4 Removing the Burner Support Rail ...................................................... 24
4.3 Griddle Removal and Replacement ............................................................ 26
4.3.1 Griddle with Removable Brackets – Removal and Replacement......... 26
4.3.2 Griddle with Fixed Brackets – Removal and Replacement .................. 30
4.4 Grill Components – Removal and Replacement ......................................... 32

Service Manual for Thermador Pro Grand Dual Fuel Ranges: PRD304EG, PRD364EDG, PRD364EDPG, PRD364ELG, PRD366EG, PRD366EPG, PRD484ECG, PRD484EEG, PRD486EDG, PRD486EDPG, PRD486ELG
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4.4.1 Grill Flame Spreader Removal and Replacement................................ 33
4.4.2 Grill Burner Removal and Replacement............................................... 34
4.4.3 Grill Hot Surface Igniter Removal and Replacement............................ 35
4.4.4 Grill Electrode Removal and Replacement .......................................... 35
4.4.5 Grill Thermostat Removal and Replacement ....................................... 36
4.4.6 Grill Orifice and Elbow Connector Removal and Replacement............ 37
4.5 Removal and Replacement of Top-Accessible Components ...................... 38
4.5.1 Jet Holder Assembly Removal and Replacement................................ 38
4.5.2 Standard Valve Removal and Replacement ........................................ 40
4.5.3 Microswitch Removal and Replacement.............................................. 41
4.5.4 Solenoid Valve for XLO Burner – Removal and Replacement............. 42
4.5.5 Solenoid Valve for Grill – Removal and Replacement ......................... 43
4.5.6 XLO Valve Removal and Replacement................................................ 44
4.5.7 Potentiometer Removal and Replacement........................................... 47
4.5.8 Manifold Removal and Replacement ................................................... 48
4.5.9 Oven Lamp Transformer Removal and Replacement.......................... 50
4.5.10 Oven Temperature Selector Removal and Replacement..................... 51
4.5.11 Five-Position Oven Function Selector Removal and Replacement...... 52
4.5.12 Oven Temperature Gauge Removal and Replacement....................... 53
4.5.13 Regulator Removal and Replacement ................................................. 54
4.5.14 Control Board Removal and Replacement........................................... 55
4.5.14.1 Control Board Removal and Replacement (Large Oven).............. 55
4.5.14.2 Control Board Removal and Replacement (Small Oven).............. 56
4.5.15 Simmer Control Board Removal and Replacement ............................. 57
4.5.16 Hot Surface Igniter Board Removal and Replacement ........................ 58
4.5.17 LED Indicator Removal and Replacement........................................... 59
4.5.18 Ignition (Spark) Module Removal and Replacement............................ 59
4.5.19 Door Latch Removal and Replacement ............................................... 60
4.5.20 Plunger Switch Removal and Replacement......................................... 62
4.5.21 Griddle and Grill Thermostat Removal and Replacement.................... 63
4.5.22 Control Panel and Bullnose Removal and Replacement ..................... 64
4.6 Removal and Replacement of Back-Accessible Components .................... 68
4.6.1 Backguard and Island Trim Removal and Replacement...................... 68
4.6.2 Back Panel Removal and Replacement............................................... 69
4.6.3 Crossmember Cover Removal and Replacement................................ 70
4.6.4 Terminal Block Removal and Replacement......................................... 70
4.6.5 Electrical Wiring Connections at the Terminal Block............................ 71
4.6.6 Cooling Fan Removal and Replacement ............................................. 71
4.6.6.1 Air Interlock Switch Removal and Replacement ........................... 72
4.6.7 Thermal Fuse Removal and Replacement........................................... 73
4.7 Removal and Replacement of Front-Accessible Components.................... 74
4.7.1 Oven Temperature Sensor Removal and Replacement ...................... 74
4.7.2 Oven Lamp and Bulb Removal, Replacement, and Diagnostics.......... 75
4.7.2.1 Oven Light Diagnostics................................................................. 75
4.7.3 Oven Door Removal, Installation, and Alignment................................. 77
4.7.3.1 Removing the Door....................................................................... 77
4.7.3.2 Installing the Door......................................................................... 77
4.7.3.3 Aligning the Door .......................................................................... 78
4.7.4 Convection Components – Removal and Replacement....................... 79
4.7.5 Broil Burner Removal and Replacement.............................................. 83
4.7.6 Bake Element Components – Removal & Replacement (Large Oven) 86
4.7.7 Bake Element Components – Removal & Replacement (Small Oven) 88
4.7.8 Door Handle Components – Removal and Replacement .................... 89
4.7.9 Door Hinge Removal and Replacement............................................... 90
4.7.10 Door Gasket Removal and Replacement............................................. 93
4.7.11 Kick Panel Removal and Replacement................................................ 94

Service Manual for Thermador Pro Grand Dual Fuel Ranges: PRD304EG, PRD364EDG, PRD364EDPG, PRD364ELG, PRD366EG, PRD366EPG, PRD484ECG, PRD484EEG, PRD486EDG, PRD486EDPG, PRD486ELG
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5Before Returning Appliance to Service...............................................94
6Clean-Up.................................................................................................95
7Additional Resources............................................................................95
7.1 QuickFinder................................................................................................. 95
7.2 Technical Support ....................................................................................... 95

Service Manual for Thermador Pro Grand Dual Fuel Ranges: PRD304EG, PRD364EDG, PRD364EDPG, PRD364ELG, PRD366EG, PRD366EPG, PRD484ECG, PRD484EEG, PRD486EDG, PRD486EDPG, PRD486ELG
58300000157422_ARA_EN_A Page 5 of 95
1 GENERAL
Thermador Pro Grand dual fuel ranges may include such features as
convection bake and convection broil, a 6-pass / 1630-watt electric
griddle, a gas grill, 6-pass bake and 8-pass broil elements for the
large oven, 6-pass bake and broil elements for the small oven,Star®
burners, and two ExtraLow® simmer burners. Compatible with natural
gas, the range is convertible to LP gas using the PLPKIT kit.
1.1 Applicable Models
This manual contains information that is necessary for servicing the
following Thermador Pro Grand dual fuel ranges:
PRD304EG
PRD364EDG
PRD364EDPG
PRD364ELG
PRD366EG
PRD366EPG
PRD484ECG
PRD484EEG
PRD486EDG
PRD486EDPG
PRD486ELG
■Due to the complexity and the risk of high-voltage electrical shock,
customers should not service their appliances.
■The information provided in this document is intended for trained,
qualified personnel only. The proper function and the safety of the
appliance can be affected by an improper repair, and even serious
threats to life or physical condition may arise. BSH Home
Appliances Corporation is not liable for damages caused by
improper repairs performed by unauthorized parties. Local codes
and standards apply and must be observed. Contact Technical
Support for further assistance at [phone].
1.2 Data Rating Plate
The data rating plate which shows the model, serial, and FD number
is located at the bottom of the range behind the kick panel, as shown
in Figure 1. Remove the kick panel to access it. The information on
the data rating plate is required when calling for technical or customer
service.
The first two digits of the FD number indicate the year the appliance
was produced. To get the year, add 20 to the first two digits (for
example, an FD number beginning with 87 was produced in 2007; a
number that begins with 88 was produced in 2008). The last 2 digits of
the FD number indicate the month the product was produced (for
example, 06 indicates the appliance was produced in June).
1.3 Wiring Diagram
The wiring diagram is located at the back side of the kick panel
(see Figure 1).
Figure 1: Data Rating Plate and Wiring Diagram Locations
1 Data rating plate (behind kick panel)
2 Wiring diagram (back side of kick panel)

Service Manual for Thermador Pro Grand Dual Fuel Ranges: PRD304EG, PRD364EDG, PRD364EDPG, PRD364ELG, PRD366EG, PRD366EPG, PRD484ECG, PRD484EEG, PRD486EDG, PRD486EDPG, PRD486ELG
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1.4 Technical Documents to Read Prior to Servicing
Before you start servicing, check QuickFinder for all documents and
information associated with this specific appliance and/or parts.
1.5 Recommended Tools and Supplies
The following are recommended to use when servicing this appliance:
mCaution
Power Drivers
If using a power driver, set the clutch to the lowest setting
Phillips screwdrivers
Flat blade screwdrivers: large, small
Precision flat-blade screwdriver with a high-strength blade,
1/8-inch [3.0mm] wide, .020-inch [0.50mm] thickness tip
Drivers: T-27, T-20, T-10
1/4 inch nut driver or 1/4 inch socket wrench / ratchet
20 mm socket
Adjustable wrenches (2)
Open-end wrench sizes: 1/4 inch, 9 mm, 11 mm, 1/2 inch,
9/16 inch, 5/8 inch, 3/4 inch, 5/16 inch, 11/32 inch,
Pipe wrench
Socket wrench / ratchet 11/32 inch
Swivel head driver with an 11/32 inch, deep-well socket
Needle-nose pliers
Hammer
Protective gloves
Gas leak test equipment
Pipe sealant
Small mirror
Air sled or dolly
Protective eye wear (such as glasses, goggles)
Flashlight
Amp meter
Thermometer with thermocouple leads
Multimeter
1.6 Important Safety Information
Before starting to service an appliance, familiarize yourself with all
safety information and precautions contained in this manual.
1.6.1 Safety Symbols Used In This Manual
Warnings alert you to dangers that may result in bodily injury or death.
mCaution
Cautions alert you to actions that may result in damage to the product,
or property.
1.6.2 Safety Precautions to Know Prior to Servicing
Before You Start Servicing the Appliance
Before disassembly, removal or installation of any component, do the
following:
■Turn off electrical power by removing the power cord from the
electrical outlet, and putting the circuit breaker in the OFF position
(or removing the fuse)
■Turn off the gas supply to the appliance
■Make sure the range and components are cool before removing or
servicing them
■Wear protective clothes: long sleeves, gloves, safety glasses
Replacement Parts
Use only authorized replacement parts for this appliance. Use of
substitutions may defeat compliance with safety standards set for
home appliances, will void the warranty, and may create safety
hazards resulting in bodily injury, death, or damage.

Service Manual for Thermador Pro Grand Dual Fuel Ranges: PRD304EG, PRD364EDG, PRD364EDPG, PRD364ELG, PRD366EG, PRD366EPG, PRD484ECG, PRD484EEG, PRD486EDG, PRD486EDPG, PRD486ELG
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Fire / Explosion Hazards
■Make sure the gas valve at the wall is closed before removing and
installing any gas components.
■Do not store or use any flammable vapors, liquids, or combustible
materials in the vicinity of this appliance.
■Do not use water on grease fires. Turn appliance off and smother
the fire with baking soda or use a dry chemical or foam-type
extinguisher.
Griddle and Grill Hazard
The griddle / grill plate must always be correctly in place when it is on.
What to Do If You Smell Gas
■Do not try to light any appliance
■Do not touch any electrical switch
■Do not use any phone or cell phone in the building
Installation and service must be performed by a qualified installer,
service agency, or the gas supplier.
Testing for Gas Leaks
■Do not ever use a flame to test for gas leaks, as doing so may
result in explosion, injury, death, and/or damage to the appliance
and property.
■With electrical power off, carefully check for gas leaks at each gas
component that was removed, replaced, or otherwise serviced
using a gas leak detector or bubble test. The only exceptions that
may require the electrical power to be on are for the XLO valves –
for these, use extreme caution when performing gas leak testing.
Electrical Hazards
■Before servicing the appliance, remove electrical power by
disconnecting the power cord from the wall receptacle, by shutting
off the circuit breaker, or by disconnecting the proper fuse.
■If tests have to be conducted while the appliance is live, always
use a residual-current-operated circuit-breaker. The protective
conductor connection must not exceed the recommended values.
■When repairs are complete, perform a function test in accordance
with the appropriate regulations.
■Do not under any circumstances cut or remove the separate
ground wire or the third (ground) prong from the power cord plug.
■Improper grounding or reverse polarization will cause malfunction
(such as continuous sparking of the igniters), which can damage
the appliance and create an electrical shock hazard. Make sure
the circuit is properly grounded and polarized in accordance with
applicable local codes and ordinances. Receptacle replacement
shall be in accordance with the National Electric Code.
Hot Surfaces
To avoid burns and injury, do not handle components and surfaces
that are hot, such as the rangetop burner assemblies, maintop,
griddle/grill, gas burners, electric elements, hot surface igniters, heat
deflector, and interior oven surfaces, or the exterior area immediately
surrounding the door.
Sharp Components
This appliance has sheet metal and other components which often
have sharp edges. When working on this appliance, avoid cutting
yourself and other injury by handling these parts with care and using
adequate protective measures, such as gloves.

Service Manual for Thermador Pro Grand Dual Fuel Ranges: PRD304EG, PRD364EDG, PRD364EDPG, PRD364ELG, PRD366EG, PRD366EPG, PRD484ECG, PRD484EEG, PRD486EDG, PRD486EDPG, PRD486ELG
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In Case of Power Outage
1. If for any reason a control knob is on when there is any failure or
removal of electrical power from the appliance (such as a power
outage), immediately turn all control knob(s) to the OFF position.
2. Ventilate by opening a door or window, and wait at least 5minutes
for all the gas to dissipate.
3. If you smell gas, refer to the applicable safety precautions stated
in this manual.
Clean-up Hazards
■Don’t allow any cleaning or polishing solutions/compounds,
disinfectants or bleaches to remain in contact with the stainless
steel surfaces for long periods, or after clean-up. These may
contain chemicals or materials which could release harmful
inhalants and can damage the appliance. After cleaning or
polishing, always rinse the cleaning/polishing materials with clear
water and wipe dry with a clean soft, non-abrasive cloth.
■Clean the range with caution. Do not use flammable cleaners to
clean the range. Avoid steam burns; do not use a wet sponge or
cloth to clean the range while it is hot. Do not use any type of
aerosol cleaner on or around the rangetop when hot. Some
cleaners produce noxious fumes if applied to a hot surface. Follow
directions provided by the cleaner manufacturer.
Fiberglass Insulation
Wear gloves when handling fiberglass insulation.
Prior to Returning Appliance to Service
Prior to returning the appliance to service, make sure that:
■All electrical connections are correct and secure
■All safety grounds (internal and external) are correctly and
securely connected
■All gas connections are secure and have been leak tested using a
gas leak detector or bubble test.
■All panels and components are properly and securely
reassembled
mCaution
Code Compliance
Local codes vary. Installation, electrical connections, gas connections,
and grounding must comply with all applicable codes.
TESTED IN ACCORDANCE WITH ANSI
Z21.1, THE STANDARD FOR HOUSEHOLD
COOKING GAS APPLIANCES. IN CANADA
TESTED IN ACCORDANCE WITH
CAN/CGA1.1 – M81, THE STANDARD FOR
DOMESTIC GAS RANGES.
Check your local building codes for the proper
method of installation. In the absence of local
codes, this unit should be installed in accordance
with the National Fuel Gas Code No. Z223.1/
NFPA 54 current issue and the National
Electrical Code ANSI/NFPA No. 70 current issue
or the Can – B149 Installation Codes for Gas
Burning Appliances and C22.1 Canadian
Electrical Code Part 1.
It is the responsibility of the owner and the
installer to determine if additional requirements
apply in specific installations.

Service Manual for Thermador Pro Grand Dual Fuel Ranges: PRD304EG, PRD364EDG, PRD364EDPG, PRD364ELG, PRD366EG, PRD366EPG, PRD484ECG, PRD484EEG, PRD486EDG, PRD486EDPG, PRD486ELG
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2 OPERATION
2.1 Knobs and Controls
The control knobs each have an icon to identify the location on the
range. The two standard burners are located on the right side of the
control panel (see Figure 2). The two ExtraLow (XLO) burners are
located on the left side (see Figure 3).
2.1.1 Standard Burner Knob
1. Press a control knob in, and turn counter-clockwise to HI setting.
The igniter for the burner clicks while sparking until flame ignition.
Burner should ignite within 4 seconds.
2. For the standard burners, rotate the knob to any setting between
HI and SIM.
NOTE: The blue LED indicator lights up when burners are lit.
Figure 2: Standard Burner Control Knob
2.1.2 ExtraLow Burner Knob
When in XLO mode - the very lowest flame setting, the flame cycles
on for approximately 8 seconds and then turns off for 52 seconds of
each minute.
1. Press a control knob in, and turn counter-clockwise to HI setting.
The igniter for the burner clicks while sparking until flame ignition.
Burner should ignite within 4 seconds.
2. In XLO mode, the knob can be set between SIM and XLO for a
variable range of low heat (see Figure 3).
Figure 3: XLO Burner Control Knob
2.1.3 Griddle Control Knob
The griddle knob controls the temperature to the griddle, from 150° F
to 500° F (see Figure 4).
Press and turn the knob clockwise to select a setting.
Figure 4: Griddle Control Knob

Service Manual for Thermador Pro Grand Dual Fuel Ranges: PRD304EG, PRD364EDG, PRD364EDPG, PRD364ELG, PRD366EG, PRD366EPG, PRD484ECG, PRD484EEG, PRD486EDG, PRD486EDPG, PRD486ELG
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2.1.4 Grill Control Knob
This knob controls the temperature to the grill. Press the control knob
and rotate it counterclockwise to the LITE position. After the flame is
completely around the burner, adjust the knob to the desired heat
setting between HI and LO.
Figure 5: Grill Control Knob
2.1.5 Temperature Selector Knob
Use this knob for setting the oven temperature, broil, and speed-clean
mode. The small oven does not have the speed-clean feature. See
Figure 6.
Figure 6: Temperature Knobs – Small Oven (Left), Large Oven (Right)
2.1.6 Five-Position Oven Function Selector Knob
For the small oven of 48-inch ranges only, use this knob for bake,
convection bake, broil, and speed-clean (see Figure 7).
Figure 7: Five-Position Oven Function Selector Knob
2.1.7 Six-Position Oven Function Selector Knob
For the large oven of 48-inch ranges and for the oven of all 30-inch
and 36-inch ranges, use this knob for bake, convection bake, broil,
convection broil, and speed-clean (see Figure 8).
Figure 8: Six-Position Oven Function Selector Knob

Service Manual for Thermador Pro Grand Dual Fuel Ranges: PRD304EG, PRD364EDG, PRD364EDPG, PRD364ELG, PRD366EG, PRD366EPG, PRD484ECG, PRD484EEG, PRD486EDG, PRD486EDPG, PRD486ELG
58300000157422_ARA_EN_A Page 11 of 95
2.1.8 Oven Lamp Switch
There is an oven lamp switch for each oven.
Figure 9: Oven Light Switch
2.2 LED Indicators
The LED indicators illuminate per current cycle. They are also used to
indicate fault codes (see Fault Codes, page 19).
Figure 10: LED Indicators
2.3 Automatic Re-Ignition
Each Star burner has its own electronic igniter that sparks when the
burner is turned on. If one or more burner blows out, the respective
igniter/electrode automatically re-ignites the flame.
2.4 Operation During a Power Outage
When there is a removal of electrical power, the XLO burners, griddle,
and grill cannot be used. Do not attempt to light them manually during
a power outage.
mCaution
Power Outage Precautions
■Ventilate well by opening a door or window, and wait at least five
minutes until all the gas dissipates.
■If you smell gas, comply with the warnings and precautions in the
Important Safety Information section (page 6) of this manual.
2.5 Maintop Components and Burner Assembly
Figure 11: Maintop Components and Burner Assembly
1 Burner cap 7 Heat shield
2 Venturi tube 8 Burner support rail
3 Burner base (brass) 9 Wire guard clip
4 Trim for spill tray 10 Jet holder assembly
5 Spill tray 11 Spring
6 Nut 12 Igniter plug (electrode)

Service Manual for Thermador Pro Grand Dual Fuel Ranges: PRD304EG, PRD364EDG, PRD364EDPG, PRD364ELG, PRD366EG, PRD366EPG, PRD484ECG, PRD484EEG, PRD486EDG, PRD486EDPG, PRD486ELG
58300000157422_ARA_EN_A Page 12 of 95
3 TESTING, ADJUSTING, TROUBLESHOOTING
BURNERS AND IGNITION
Servicing Burners and Ignition
Burner and ignition servicing must be performed by a qualified
technician. Improper adjustments may be dangerous, cause damage
or harmful by-products, and may void the appliance warranty.
Ignition Hazard
Do not touch burners when the igniters are active (sparking).
3.1 Before Testing
Before testing rangetop burners and ignition, do the following:
1. Re-install any loose components that may have been removed
earlier, such as burner caps, griddle, and grates. Be certain that
burner caps seat properly into the burner bases, burner bases and
Venturi tubes are aligned correctly, and that the ignition wires are
properly positioned.
2. To test for gas leaks, make sure the electrical power is removed
and the manual gas shut-off valve is open, and then carefully
check range components and gas supply for leaks using a gas
leak detector or bubble test.
3. After gas checks are complete and before testing, connect the
range to the electrical power supply.
3.2 Rangetop Burner Characteristics
If one or more rangetop burner blows out, the respective igniter
electrode automatically re-ignites the flame.
The flame should burn through each burner port, completely around
the burner cap (see Figure 12).
Figure 12: Burner Ports
1 Burner port
It is normal to hear the following during burner operation:
A slight sound that is associated with gas combustion and
ignition. There should not be a loud noise.
A clicking noise every time the gas cycles, coming from the
solenoid valves of the two left burners
If using LP gas, a slight “pop” sound may be heard at the burner
ports a few seconds after the burner has been turned off

Service Manual for Thermador Pro Grand Dual Fuel Ranges: PRD304EG, PRD364EDG, PRD364EDPG, PRD364ELG, PRD366EG, PRD366EPG, PRD484ECG, PRD484EEG, PRD486EDG, PRD486EDPG, PRD486ELG
58300000157422_ARA_EN_A Page 13 of 95
3.3 Rangetop Flame Characteristics
Natural gas: The Star burner flame color should be blue with no
yellow on the tips (see Figure 13). It is not uncommon to see orange
in the flame color; this indicates the burning of airborne impurities in
the gas, and will disappear with use. See Figure 14 for additional
flame characteristics.
LP gas: Slight yellow tips on the primary flame cone are normal and
may appear after a few minutes. The flame should be stable with no
excessive noise or fluttering. Orange colored streaks in the flame are
produced from burning airborne debris, which is normal at startup,
and should dissipate in a few minutes (see Figure 14).
When the flame is properly adjusted, it should burn completely around
the burner cap, at each burner port (see Figure 12).
Figure 13: Correct Flame Color and Characteristics for Natural Gas
1 Dark blue
2 Secondary cone
3 Light blue
4 Primary cone
Figure 14: Additional Flame Characteristics
NOTE: If rangetop burner/flame characteristics are not adequate, see
Troubleshooting Burner, Flame, Ignition, and Elements, page 16.

Service Manual for Thermador Pro Grand Dual Fuel Ranges: PRD304EG, PRD364EDG, PRD364EDPG, PRD364ELG, PRD366EG, PRD366EPG, PRD484ECG, PRD484EEG, PRD486EDG, PRD486EDPG, PRD486ELG
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3.4 Testing Rangetop Burner Ignition
Ignition Hazard
Do not touch the rangetop burners when the igniters are sparking.
For each burner, push the control knob in and then turn counter-
clockwise to HI. The igniter should produce a clicking sound as the
burner is sparking, and the burner should light within four seconds.
3.4.1 Testing Ignition for HI, Medium, and Low Settings
Set the burner knob to HI, and observe flame characteristics
(see Figure 13 and Figure 14). If any burner flame burns primarily
yellow, verify if the burner cap is positioned properly on the burner
base, and then re-test. Repeat test for MEDIUM and SIM settings.
If flame characteristics do not improve, call Thermador technical
support at [phone].
3.4.2 Testing Ignition for XLO Setting
The left-front and left-back burners have the XLO feature. Set the
burner knob to a setting between SIM to XLO and observe if the flame
cycles correctly – it should be on for approximately 8 seconds, and
then off for approximately 52 seconds of each minute.
3.5 Adjusting Grill Burner Flame with the Air Shutter
[Models with grill only]: The grill’s gas burner has an air shutter
system that is factory pre-set to burn optimally, but depending on the
quality of the gas available, may require adjustment (see Figure 15).
Figure 15: Typical Air Shutter
1 Air shutter
2 Adjustment screw
3 Opening
1. First remove the grill burner from the grill burner box (see Grill
Components – Removal and Replacement, page 32).
2. Loosen the adjustment screw, and then rotate the air shutter to
modify the opening as follows:
If the flame is lifting or blowing, or is not carrying over, rotate
the shutter clockwise to set the opening to a more closed
position.
If the flame is too yellow, rotate the shutter counter-clockwise
to set the opening to a more open position.
3. Tighten the adjustment screw.
4. Re-install the grill burner (see Grill Components – Removal and
Replacement, page 32).
5. Test to evaluate the flame characteristics.
6. Repeat procedure as needed until flame characteristics are
optimal.

Service Manual for Thermador Pro Grand Dual Fuel Ranges: PRD304EG, PRD364EDG, PRD364EDPG, PRD364ELG, PRD366EG, PRD366EPG, PRD484ECG, PRD484EEG, PRD486EDG, PRD486EDPG, PRD486ELG
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3.6 Adjusting Rangetop Burner Valves Manually
Figure 16: Bypass Screw on Valve (View with Control Panel Removed
for Clarity)
1 Bypass screw on XLO valve and standard valve
Although pre-adjusted, if you need to set the XLO valves and
standard valves for the lowest possible flame setting, then manually
adjust the bypass screws on the valves.
3.6.1 Special Tools Needed
To reposition the bypass screws for minimum flow settings on
manual valves, use a precision high-strength blade screwdriver,
with a 1/8 inch [3.0mm] wide, .020-inch [0.50mm] thickness tip.
3.6.2 Adjusting the Bypass Screws
1. Turn off electrical power by unplugging the power cord, or putting
the circuit breaker in the OFF position.
2. Remove knobs from valve stems by slowly pulling knobs straight
out, away from control panel.
3. For newer models: Remove and retain the two bezel mounting
screws and remove the bezel.
4. For older models: Valve screws can be accessed directly
through the control panel, without removing the bezel mounting
screws.
5. To engage the valve screw, insert the precision screwdriver with a
1/8 inch blade into the same hole in the bezel that was created by
the removal of the right side mounting screw (see Figure 18,
page 16).
6. Turn the valve screw clockwise just until "bottom out" position is
reached. Do not over-tighten the valve screw (see Figure 18).
NOTE: The two valves for XLO operation (farthest left on control
panel) must be in the OFF position for proper access to the valve
screws through clearance holes in the XLO potentiometers.
NOTE: The griddle/grill is controlled by a thermostat and does not
have a valve that requires adjustment.
Gas Leaks
With electrical power off, carefully check for gas leaks at each gas
component that was removed, replaced, or otherwise serviced
using a gas leak detector or bubble test. For XLO valves (not
standard valves), you may need the electrical power to be on
when testing for gas leaks. Use extreme caution when
performing gas leak testing on XLO valves.

Service Manual for Thermador Pro Grand Dual Fuel Ranges: PRD304EG, PRD364EDG, PRD364EDPG, PRD364ELG, PRD366EG, PRD366EPG, PRD484ECG, PRD484EEG, PRD486EDG, PRD486EDPG, PRD486ELG
58300000157422_ARA_EN_A Page 16 of 95
Figure 17: Removing the Bezel Mounting Screws
1 Bezel mounting screws (2)
Figure 18: Accessing the Bypass Screw on the Valve
1 Bypass screw access location (shown with bezel
mounting screws and bezel removed)
3.7 Troubleshooting Burner, Flame, Ignition, and
Elements
3.7.1 Burner and Flame Diagnostics for Rangetop Burners
If a rangetop burner clicks (sparks) constantly or if burner doesn’t light
correctly and/or has inadequate burner/flame characteristics (per
Rangetop Burner Characteristics, page 12 and Rangetop Flame
Characteristics, page 13), then do the following:
Check if the manual shut-off valve is open and the unit is receiving
gas.
Check if the burner cap is properly aligned on the burner base.
Check if the burner port is open and not clogged or blocked.
Check if the igniter electrode is free from debris and is sparking.
If it is suspect that air is in the gas supply lines and system, you
can purge the remaining air by operating one of the burners for
several minutes.
Check if a fuse has blown or a circuit breaker has tripped.
For constant sparking, check wiring connections at ignition (spark)
module and electrode, and also check grounding
Refer to the Ignition Diagnostics, page 16.
Call Thermador technical support at [phone] for assistance
if any burners fail to light, or any burners continue to burn yellow.
3.7.2 Ignition Diagnostics for Rangetop Burners
The following flowchart applies in the event a burner fails to ignite.
Before performing steps in the Rangetop Burner Ignition - Diagnostic
Flowchart (Figure 19, page 17), remove electrical power from
appliance during disassembly and during removal and installation
procedures. Restore electrical power when testing the unit if it is
re-assembled.

Service Manual for Thermador Pro Grand Dual Fuel Ranges: PRD304EG, PRD364EDG, PRD364EDPG, PRD364ELG, PRD366EG, PRD366EPG, PRD484ECG, PRD484EEG, PRD486EDG, PRD486EDPG, PRD486ELG
58300000157422_ARA_EN_A Page 17 of 95
Figure 19: Rangetop Burner Ignition - Diagnostic Flowchart

Service Manual for Thermador Pro Grand Dual Fuel Ranges: PRD304EG, PRD364EDG, PRD364EDPG, PRD364ELG, PRD366EG, PRD366EPG, PRD484ECG, PRD484EEG, PRD486EDG, PRD486EDPG, PRD486ELG
58300000157422_ARA_EN_A Page 18 of 95
3.7.3 Element Diagnostics
Use the Element Cycle/Circuit Specification chart for troubleshooting
all elements as well as the hot surface igniter (HSI) for the grill.
3.7.3.1 Safety Practices for Element Diagnostics
Observe all pertinent safety practices such as warnings, cautions and
instructions contained in the Safety Precautions to Know Prior to
Servicing section of this manual (page 6), throughout this manual, and
the Installation Manual. Ensure compliance with all applicable codes.
3.7.3.2 Element Diagnostic Tips
Wiring Diagram
The electrical wiring diagram is located behind the kick panel of
the range (see Wiring Diagram, page 5).
Resistance Reading
You can perform a resistance reading on an element with the
electrical power to the range turned off.
Amperage Reading for all Elements and Grill HSI:
For an element, check either of the wires with an amp meter and
amp clamp. For the grill HSI, check at one of its wire connectors,
as the gas burner attached to HSI will ignite. NOTE: Although the
grill HSI may be glowing, if not enough current is running through
it, the safety valve may fail.
Alternatively, you can check the element and grill HSI from the
corresponding I/O relay terminals on the control board.
Alternatively, you can check an element and grill HSI from the hot
terminals (L1, L2) and neutral terminal at the terminal block.
Temperature Reading
Do not remove the thermocouple prematurely when the oven is hot.
Test oven temperature using a thermometer with a thermocouple
lead. If you leave the thermocouple in the oven during a speed
clean cycle, keep in mind it will take a few hours before the oven
is cool enough if you plan to retrieve the thermocouple.
3.7.3.3 Element Cycle/Circuit Specification
Cavity Cycle (Element/s) Mode Watts Volts Amps Ohms
18 inch Bake (Bake element) Active 4000 240 16.7 14.4
18 inch Broil (Broil element) Active 2600 240 10.8 22.2
30 inch Bake (Bake element) Active 6000 240 25.0 43.2
30 inch Broil (Broil element) Active 4000 240 16.7 14.4
Preheat 6000 240 25.0 43.2
30 inch
Convection Bake
(Bake and Broil elements are
on during Preheat mode. Bake,
Broil, and Convection elements
are on in active mode, although
Broil is only on for 4 seconds of
every minute for browning)
Active 8750 240 36.5 113.0
Preheat 4750 240 19.8 49.7
30 inch Convection Broil
(Broil and convection elements) Active 4750 240 19.8 49.7
30 inch Speed Clean
(Broil and Bake elements) Active 6000 240 25.0 43.2
36 inch Bake (Bake element) Active 6000 240 25.0 43.2
36 inch Broil (Broil element) Active 4000 240 16.7 14.4
Preheat 6000 240 25.0 43.2
36 inch
Convection Bake
(Bake and Broil elements are
on during Preheat mode. Bake,
Broil, and Convection elements
are on in active mode, although
Broil is only on for 4 seconds of
every minute for browning)
Active 8750 240 36.5 113.0
Preheat 4750 240 19.8 49.7
36 inch
Convection Broil
(Broil & convection elements on
for Preheat and active modes) Active 4750 240 19.8 49.7
36 inch Speed Clean
(Broil and Bake elements) Active 6000 240 25.0 43.2
N/A Griddle (Griddle element)
NOTE: For specific 36-inch and
48-inch models. Active 1600 120 13.3 9.0
N/A Grill Hot Surface Igniter (HSI)
NOTE: For specific 36-inch and
48-inch models. Active 120 to
48 120 0.4 to 1.0 300 to 120

Service Manual for Thermador Pro Grand Dual Fuel Ranges: PRD304EG, PRD364EDG, PRD364EDPG, PRD364ELG, PRD366EG, PRD366EPG, PRD484ECG, PRD484EEG, PRD486EDG, PRD486EDPG, PRD486ELG
58300000157422_ARA_EN_A Page 19 of 95
3.8 Fault Codes
When a fault is detected, this appliance will display a fault code
(see Figure 23, on page 20). The fault codes are represented by the
manner in which two blue LED indicators are blinking.
Depending on the range model, the blue LEDs that blink are located
either horizontally or vertically on the control panel. The horizontal
positioned blue LEDs (see Figure 20 and Figure 21) will first blink on
the left and then the right, and the vertical positioned blue LEDs (see
Figure 22) will first blink on the top and then the bottom.
For example, if the first LED blinks 4times followed immediately by
the second LED blinking 3times, that represents a fault code of 43 on
the chart (see Figure 23, on page 20).
Figure 20: Two Horizontal LED Indicators
Figure 21: Three Horizontal LED Indicators (Only Blue LEDs Blink)
Figure 22: Two Vertical LED Indicators

Service Manual for Thermador Pro Grand Dual Fuel Ranges: PRD304EG, PRD364EDG, PRD364EDPG, PRD364ELG, PRD366EG, PRD366EPG, PRD484ECG, PRD484EEG, PRD486EDG, PRD486EDPG, PRD486ELG
58300000157422_ARA_EN_A Page 20 of 95
Figure 23: Fault Codes

Service Manual for Thermador Pro Grand Dual Fuel Ranges: PRD304EG, PRD364EDG, PRD364EDPG, PRD364ELG, PRD366EG, PRD366EPG, PRD484ECG, PRD484EEG, PRD486EDG, PRD486EDPG, PRD486ELG
58300000157422_ARA_EN_A Page 21 of 95
4 SERVICE AND REPAIR
4.1 Preparing the Range for Servicing
For most servicing of this appliance (for example, involving
disassembly, or component removal / installation), you will need to do
the following prior to starting:
■Turn off the gas supply to the range by closing the gas valve at
the wall
■Turn off the electrical power to the range by removing the power
cord from the electrical outlet, and putting the circuit breaker in the
OFF position (or removing the fuse)
■Make sure the range components are not hot before servicing
■Wear protective clothes: long sleeves, gloves, safety glasses
If testing the appliance requires the use of electrical power and/or an
open gas supply, exercise extreme caution.
4.2 Accessing Components under the Maintop
This section contains the steps required to gain access to the
components located under the maintop(s).
4.2.1 Removing Knobs, Grates, Trim, Burner Assemblies
To access and service components located underneath the maintops
(see Figure 11), first remove the knobs, grates, trim, and burner
assemblies. Then remove spilltrays, heat shields, and burner support
rail(s).
1. [Optional – only if a component attached to a knob needs
replacing] Remove knob from valve stem by slowly pulling knob
straight out, away from control panel.
2. Remove all grates.
3. Remove all trim from the maintop (see Figure 24).
Figure 24: Trim
4. Remove all Star burner caps (see Figure 25).
5. Use a 20 mm socket to remove the Venturi tube from the
receptacle in the brass burner base (see Figure 25).
Figure 25: Star Burner Assembly
1 Burner cap
2 Igniter plug (electrode) – with spring
3 Burner base (brass)
4 Venturi tube