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Gas Ranges and Ovens

Gas ranges, ovens, and cooktops are designed on the basis of using the heat

generated by combustion to cook the food. The types of fuels that feed gas

appliances are:

Natural gas Natural gas is lighter than air and has a heating value between 900

and 1200 BTUs.

Liquefied petroleum (LP or LPG) LP gas is heavier than air and has a heating

value between 2500 and 3200 BTUs.

Mixed gas Mixed gas is lighter than air and has a heating value between 700 and

900 BTUs.

Manufactured gas Manufactured gas is lighter than air and has a heating value

between 500 and 700 BTUs.

To sustain combustion in a range, oven, or cooktop, an ignition source, such as a flame or

by electrical means, is used to ignite the gas vapors. To ignite these gases, the temperature

will have to be between 900 and 1200 degrees Fahrenheit.

The pressure of natural gas that is supplied to a residence will vary between a five- and

nine-inch water column. LP or LPG gas pressure for residential appliances, as established

by the gas industry, will be between a nine- and eleven-inch water column. To determine

the correct pressure rating, the technician must refer to the manufacturer’s specifications or

the installation instructions for that product. The two most common types of gas used in

homes are LP and natural gas.

On some models, electricity (120 volts) is supplied to the gas appliance for ignition,

temperature control, safety valve, electronic controls, and accessories (clock, lights, etc.).

Gas cooking appliances are available in a wide variety of styles also. Figures 1-1, 1-4, and

23-1 are just a small sampling.

This chapter will provide the basics needed to diagnose and repair gas cooking appliances.

Figure 23-2 identifies where components are located within the gas range. This illustration

is used as an example only. The actual construction and features might vary, depending on

the brand and model you are servicing.

801

CHAPTER

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FIGURE 23-1 A ive-burner gas cooktop with sealed burners.

Oven control

Manual oven

light switch

Door latch

switches and door

latch solenoid

Oven light

Temperature sensor

Automatic oven

light switch

Gas safety

valve

Bake burner

and ignitor

Pressure

regulator

Gas valve and

spark ignitor

switch

Door latch

Broil burner

and ignitor

Burner ignitor

Ignitor spark module

Console

Conventional

burner

FIGURE 23-2 The locations of components in a gas freestanding range.

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Principles of Operation

When the gas is turned on (standing pilot ignition system), whether by a knob or automatically

by a control device, gas will begin to flow from the supply line through a gas pressure

regulator into the gas manifold for distribution to the burners or to the oven safety valve

(Figure 23-3). The gas travels from the manifold through the controls, passing through the

orifice into the venturi throat and mixing tube. The air-gas mixture then enters the burner

head, exits through the burner ports, and travels through the flash tube to the pilot flame

(Figure 23-4). Once ignited, the flame begins to travel back through the flash tube to the

charge ports and climber ports and burns evenly around the burner head.

FIGURE 23-3 A top view of a standing pilot ignition system, illustrating the component locations in a

freestanding gas range. See inset for pilot lame height.

Surface burner

Pilot flame size

Inset

Bracket

1/4"

Flame

Pressure

regulator

valve

Pilot flame

or spark ignitor

Flash tube

Burner

heads

Gas supply

tube

Pilot

adjustment

screw

Main gas shutoff valve

Surface burner controls

Oven

control

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When the oven thermostat is turned on, gas flows from the manifold (Figure 23-5)

through the thermostat and to the safety valve. The thermostat also feeds gas through the

pilot gas line to the pilot assembly. The pilot flame will increase in size, heating the safety

valve-sensing bulb (Figure 23-6), opening up the safety valve and allowing gas to flow to

the burner. When the air-gas mixture flows out of the oven burner, it encounters the pilot

flame and the burner ignites. When the oven cavity temperature is satisfied, the gas flow

will stop to the oven burner and the gas flow to the pilot assembly will decrease to the

standing pilot light.

On models with electronic ignition, the standing pilot is replaced with ignitor switches,

surface burner electrodes, and a spark module (Figures 23-7, 23-8, 23-9, and 23-10). When

the consumer turns the burner control knob to the “lite” position, a switch within the ignitor

switch will close, supplying 120 volts through the ignitor switch to the spark module. Some

spark modules will produce a high-voltage pulse to the ignitor every two seconds at very

low amperage (4 milliamps). Some models use a spark module that will produce two to

three sparks per second. This pulse will produce a spark between the ignitor electrode and

the ignitor-grounding strap (see Figure 23-8). At the same time, the gas will begin to flow

from the supply line through a gas pressure regulator into the gas manifold for distribution

to the burners. When the burner is lit, the control knob will then be turned to the “on”

position, where the height of the flame can be adjusted. When this occurs, the switch within

the ignitor switch will open, turning off the voltage to the spark module (see Figure 23-7).

Top burner ports

Climber ports

Charge ports

Flash tube

Flash

tube

Pilot flame (inside shield)

Pilot f lame

FIGURE 23-4 The air-gas mixture is traveling through the burner ports and lash tube, encountering the

pilot lame and igniting the burner.

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When the oven thermostat is turned on and set to the desired temperature, a switch

contact from within the thermostat will close. This action will complete the circuit,

supplying 120 volts to the glow-bar ignition system (Figure 23-11). The glow-bar ignitor

(Figure 23-12) must heat up to 2000 degrees Fahrenheit, allowing 2.5 to 4.0 amps to flow to

the safety valve. As the bimetal warps, the safety valve will open, allowing the gas to flow

through the orifice into the venturi throat and mixing tube. The air-gas mixture then enters

the oven burner head, exits through the burner ports, and travels to the glow-bar ignitor,

igniting the oven burner. Once ignited, the flame begins to burn evenly around the burner

head. The entire process takes about 60 to 90 seconds to complete.

The self-cleaning operation in a gas range is similar to that of the electric range (see

Chapter 22). The only difference is that some models use two burners (Figure 23-13). The

broil burner allows the consumer to broil food in the same oven cavity. In the self-cleaning

mode, both burners do not come on at the same time. As Figure 23-13 shows, the burners

are controlled by the electronic control to operate the dual safety valve and the glow-bar

FIGURE 23-5 The components that make up the oven burner system with a standing pilot ignition

system.

Pilot gas line

Pilot

assembly

Oven burner

Pilot flame

sensing bulb and

capillary tube

Safety

valve

Manifold

Gas in

Oven

thermostat

Sensing bulb and

capillary tube

Main gas line

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ignitors. When the oven cavity temperature reaches 600 degrees Fahrenheit, the door latch

lock light will come on, locking the oven door and preventing the consumer from opening

it. When the oven cavity temperature stabilizes (between 840 and 920 degrees Fahrenheit),

the cleaning process begins. This cleaning process requires approximately two to three

hours. When the self-cleaning cycle is complete, the burners turn off and the oven begins to

cool down. When the oven cavity temperature drops below 600 degrees Fahrenheit, the

oven latch lock light will go off, allowing the consumer to open the oven door.

Standing pilot

assembly

(a)

Standing

pilot flame

Thermostat off

200

250

300

350

400 450

500

550

Broil

OFF

Flame spreader

Safety valve

sensing bulb

(b)

Pilot flame spreads

down to sensing bulb

1234

mostat on

250

300

350

400 450

500

550

Broil

OFF

200

FIGURE 23-6 When the thermostat control knob is in the “off” position, the pilot lame stands up.

With the thermostat control knob turned on, the pilot lame will increase in size, heating the safety

valve-sensing bulb.

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C h a p t e r 2 3 : G a s R a n g e s a n d O v e n s 807

Safety First

Any person who cannot use basic tools or follow written instructions should not attempt

to install, maintain, or repair any gas range, oven, or cooktop. Any improper installation,

preventive maintenance, or repairs could create a risk of personal injury or property damage.

If you do not fully understand the installation, preventive maintenance, or repair procedures

in this chapter, or if you doubt your ability to complete the task on your appliance, please call

your service manager.

FIGURE 23-7 The electronic ignition switch is mounted over the surface burner valve stem. 1. When the

knob is in the “off” position, the contact switch is open and there is no gas low. 2. The knob is set in

the “lite” position, the contact switch is closed, and gas lows to the burner. 3. When the knob is turned

to the “on” position, the ignitor switch will open, breaking the circuit, and gas lows to the burner.

To ignitor spark module

Manifold

Gas valve

Stem

Ignitor switch

Ignitor switch Contacts

open

ON

LITE

OFF

ON

OFF

LITE

LITE

OFF

ON

Burner off

Switch contacts open

Burner off

Switch contacts open

Burner lit

Burner off

Switch contacts closed

Ignitors sparking

Contacts

open

1 2 3

Contacts

closed

90°

Rotating

collar stop

Terminal

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The following precautions should also be followed:

Always follow the use and care guide instructions from the manufacturer.

Never use a range to heat the home; it simply was not designed for that purpose.

Keep the cooking area clean of soot, spills, and grease.

Do not use flammable liquids near a cooking appliance.

When repairing the range, always use the proper tools.

Always reconnect the wires to the range after repairs have been made.

Before servicing any gas components in the range, turn off the gas supply.

Always have a fire extinguisher nearby in case of mishaps that might lead to a fire.

Make sure that gas appliances have proper venting according to the manufacturer’s

recommendations.

To eliminate personal injury or fire when operating the appliance, avoid using the

storage cabinets above the product.

Before continuing, take a moment to refresh your memory of the safety procedures in

Chapter 2.

Do not store any flammable materials near a gas appliance, and avoid ignition sources in the

event you smell gas leaking. Make sure you have proper ventilation when servicing the gas appliance

to prevent carbon monoxide (CO) poisoning.

To ignitor

switches

Spark

module

To ignitor electrode

(a) (b)

Ceramic

insulated body

Ground strap

(bracket)

Metal rod

Electrode wire

To spark module

Surface burner

ignitor (electrode)

FIGURE 23-8 (a) A typical spark module. (b) The surface burner ignitor and grounding bracket.

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C h a p t e r 2 3 : G a s R a n g e s a n d O v e n s 809

Gas Ranges, Ovens, and Cooktops in General

Much of the troubleshooting information in this chapter covers gas ranges, ovens, and

cooktops in general, rather than specific models, in order to present a broad overview of

service techniques. The illustrations that are used in this chapter are for demonstration

purposes only to clarify the description of how to service these appliances. They in no way

reflect on a particular brand’s reliability.

FIGURE 23-9 The components that make up the standard burner system using an electronic ignition

system to light the burner.

Ignitor

spark

module

Highvoltage

pulses Spark

Spark

ignitor Ground strap

(bracket)

Flash

tube

Conventional

burner

Climber

ports (3)

Ignitor switch

Gas

manifold

Pressure

regulator

Gas inlet

Gas flow

Gas flow

Gas valve

Air

shutter

Venturi throat

Burner

control knob

120 VAC

Line voltage

OFF

LITE

810 P a r t V I : A p p l i a n c e S e r v i c e , I n s t a l l a t i o n , a n d P r e v e n t i v e M a i n t e n a n c e P r o c e d u r e s

Location and Installation of Gas Range, Oven, and Cooktop

Locate the range, oven, or cooktop where it will be well lighted and have access to proper

ventilation. The range must be level for proper baking and cooking results. The range might

be installed adjacent to the left and/or right base cabinets and against a rear vertical wall

(for the “anti-tip” cleat). A wall oven must be installed on a supporting surface that is strong

enough to support the weight of the oven and its contents while remaining level from side

to side and from front to rear. A cooktop must be installed on a flat surface, supported by

the countertop, and it should be level. Contact your flooring company to check if the

flooring can withstand a minimum of 200 pounds. It is also recommended that you contact

your builder to determine if the cabinets and walls can withstand the heat produced by the

gas appliance. Some kitchen cabinets and building materials were not designed to withstand

the heat that is given off by the product.

The proper installation instructions for your model are included with the appliance.

These instructions will assist you with the installation requirements (dimensions, electrical

requirements, cutout dimensions, venting, etc.) needed to complete the installation according

to the manufacturer’s specifications.

Pressure

regulator

Gas

manifold

Gas inlet

Burner

control knob

OFF

LITE

Ignitor switch

Gas valve

Air

shutter

Burner flame

Burner cap

High-voltage

pulses

120 VAC

Line voltage

To spark

ignitor

Ignitor spark module

Burner

Spark

Spark ignitor

Venturi throat

Gas flow

Gas flow

FIGURE 23-10 The components that make up the sealed burner system using an electronic ignition

system to light the burner.

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C h a p t e r 2 3 : G a s R a n g e s a n d O v e n s 811

120-volt

supply

Oven

burner

Glow-bar

ignitor

Pressure

regulator

Main gas

inlet

Oven

thermostat

Sensing bulb and

capillary tube

Manual

gas shutoff

valve

Safety

valve

FIGURE 23-11 The components that make up the oven burner system using a glow-bar ignition system

to light the burner.

FIGURE 23-12 A typical glow-bar ignitor.

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Some gas appliance models are equipped with electronic controls and electronic

ignition. The electrical plug that is considered for use must be properly polarized and

grounded in order for the electronic controls to function properly. The appliance chassis

must also be grounded so that the electronics in the product will function properly.

Step-by-Step Troubleshooting by Symptom Diagnosis

When servicing an appliance, don’t overlook the simple things that might be causing the

problem. Step-by-step troubleshooting by symptom diagnosis is based on diagnosing

malfunctions, with their possible causes arranged into categories relating to the operation of

the gas cooking appliance. This section is intended only to serve as a checklist to aid you in

Main gas

inlet

Pressure

regulator

Dual safety valve 120-volt

supply

Wires to

bake relay

Wires to

broil relay

Bake burner

Glow-bar

ignitors

Broil burner

Broil gas

line

FIGURE 23-13 The components that make up the self-cleaning oven system using two glow-bar ignitors

to light the burners. The consumer can bake or broil in the same oven cavity.

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C h a p t e r 2 3 : G a s R a n g e s a n d O v e n s 813

diagnosing a problem. Look at the symptom that best describes the problem that you are

experiencing with the range, oven, or cooktop, and then proceed to correct the problem.

Gas Odors

Check the pilot light.

Check for a gas leak in the supply line.

Check the ventilation system.

Check the burner controls. When not in use, the controls must be completely turned off.

Check the regulator.

Surface Burner Will Not Light

Check the pilot light.

Check the pilot burner port holes for a blockage.

Check for 120 volts to the appliance. Check fuses or circuit breakers.

On electronic models, check the ignition system.

Check the burner openings for a blockage.

Check the air-gas mixture.

Check for a blockage in the gas supply to the appliance and burner.

Make sure that the gas supply is turned on.

The Pilot for the Surface Burner Will Not Stay Lit

Check the burner for blockages.

Check the setting and adjust the pilot light.

Check the air-gas mixture.

Check for a blockage in the gas supply to the appliance and burner.

Check for a wind source that may affect the pilot light.

The Surface Burner Flame Is Too Low

Check the burner assembly for blockages.

Check the air-gas mixture.

Check for a blockage in the gas supply to the appliance and burner.

Test the gas pressure to the appliance and make corrections, if necessary.

Check and make sure that the range/oven is converted to the correct gas type

(LP or natural).

The Surface Burner Flame Is Too High

Check the air-gas mixture.

Test the gas pressure to the appliance and make corrections, if necessary.

Check and make sure that the range/oven is converted to the correct gas type

(LP or natural).

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The Oven Burner Will Not Light or Stay Lit

Check the pilot light. If the pilot is too small, adjust the height.

Check the control settings on the clock or electronic controls.

Check for 120 volts to the appliance.

Check the ignition system.

Check the fuses in the appliance.

Check the glow-bar ignitor.

Check the selector switch, thermostat, and the safety valve for proper operation.

Check for a blockage in the pilot light.

Test the gas pressure to the appliance and make corrections, if necessary.

Check and make sure that the range/oven is converted to the correct gas type

(LP or natural).

On electronic models, check for unusual display readouts and/or error codes.

Oven Temperature Will Not Hold

Check the oven temperature and thermostat control.

Check for a blockage in the oven burner.

Check the oven door and gasket.

On electronic models, check for unusual display readouts and/or error codes.

Self-Cleaning Function Is Not Working

Check the controls for the proper settings.

Check the door latch assembly. Make sure the latch engages.

Check the thermostat and the selector switch for proper operation.

Check for 120 volts to the appliance.

Check the door alignment and gasket.

On electronic models, check for unusual display readouts and/or error codes.

The Burner Orifice Squeals

Check the orifice opening for debris.

Make sure that the correct orifice size is in use.

Test the gas pressure to the appliance and make corrections, if necessary.

Supply Air Is Noisy

Check the venturi throat and mixing tube for debris and rough edges.

Check the burner positioning over the orifice.

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C h a p t e r 2 3 : G a s R a n g e s a n d O v e n s 815

Erratic Burner Flame

Check the gas pressure at the gas regulator.

Check the burner controls for proper operation.

Yellow or Sooty Burner Flame

Make sure that the burner is in the correct position.

Check the air-gas mixture.

Test the gas pressure to the appliance and make corrections, if necessary.

Gas Appliance Maintenance

To maintain gas appliances, always follow the manufacturer’s recommendations for

periodic maintenance as stated in the use and care manual. The range, oven, or cooktop can

be cleaned with warm water, mild detergent, and a soft cloth on all cleanable parts, as

recommended in the use and care manual. Also, never use abrasive cleaners that are not

recommended by the manufacturer.

Do not allow grease spillovers to accumulate on top of the range after cooking; they will

become a fire hazard. When cleaning the burners, always make sure that all of the portholes

are free of debris. If, for any reason, the burner portholes are blocked, the flame appearance

will be different. Blocked portholes will reduce gas flow and the heating valve of the burner

will be reduced.

Repair Procedures

Each repair procedure is a complete inspection and repair process for a single range, oven,

or cooktop component, containing the information you need to test a component that might

be faulty and replace it, if necessary.

Any person who cannot use basic tools should not attempt to install, maintain, or repair

any electric dryer. Any improper installation, preventative maintenance, or repairs will

create a risk of personal injury, as well as property damage. Call the service manager if

installation, preventative maintenance, or the repair procedure is not fully understood.

Gas Burner Valve

The gas burner valve is mounted on the manifold and it supplies gas to the burners.

The typical complaints associated with the burner valve are:

It is hard to turn on.

When the gas burner valve is on, little or no gas comes out.

There is a gas smell around the burner valve.

Unusual display readouts and/or error codes.

816 P a r t V I : A p p l i a n c e S e r v i c e , I n s t a l l a t i o n , a n d P r e v e n t i v e M a i n t e n a n c e P r o c e d u r e s

To handle these problems, perform the following steps:

1. Verify the complaint. Verify the complaint by testing for gas leaks. Next, turn on

the burners. Is the pilot light on? Are the electronic switches working?

2. Check for external factors. You must check for external factors not associated with

the appliance. Is the appliance installed properly? Are there 120 volts to the

appliance? The voltage at the receptacle is between 108 volts and 132 volts during a

load on the circuit. Do you have the correct polarity? (See Chapter 6.) Is the gas

turned on?

3. Disconnect the electricity. Before working on the appliance, disconnect the

electricity. This can be done by pulling the plug from the electrical outlet. Or

disconnect the electricity at the fuse panel or at the circuit breaker panel. Turn off

the electricity.

WARNING Some diagnostic tests will require you to test the components with the power turned on.

When you disassemble the control panel, you can position it in such a way that the wiring will

not make contact with metal. This act will allow you to test the components without electrical

mishaps.

4. Shut off the gas supply. Before you begin servicing any gas components, shut off

the supply of gas to the appliance. The shutoff valve should be within 6 feet of the

gas appliance.

5. Gain access to the gas burner valve. To gain access to the gas burner valve, lift the

cooktop, pull off the control knobs, and then remove the screws from the front

panel (Figure 23-14). Remove the control panel. This will expose the gas burner

valve and manifold (Figure 23-15).

6. Remove the gas burner valve. To remove the gas burner valve, remove the screw

that secures the burner to the burner bar, and then lift the burner head up and out

of the range (Figure 23-16). With the gas burner valve still attached to the gas

manifold, remove the orifice with a wrench, turning it counterclockwise. Now

remove the gas burner valve by removing the mounting screw that is secured to the

manifold right above the valve (see Figure 23-15). Remove the valve. On some

models you might have to completely remove the manifold from the range in order

to remove the screw that secures the valve to the manifold.

7. Install a new gas burner valve. To install a new gas burner valve, just reverse the

disassembly procedure, and reassemble. Be careful not to damage the washers

when reinstalling the gas burner valve (see Figure 23-15). Most gas ranges, ovens,

and cooktops have universal orifices. When you remove the orifice, you must reinstall

that orifice for the type of gas supplied to the range. For natural gas, the orifice must

be tightened down clockwise about two to three turns, making sure that the gas LP

insert rests against the orifice cap, then unscrew counterclockwise the orifice cap

about two and a half turns (Figure 23-17a). For LP gas, the orifice will tighten down

only two and a half times, resting against the gas LP insert (Figure 23-17b). If the

orifice is tightened down too much the gas flow will be restricted. Reinstall the front

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C h a p t e r 2 3 : G a s R a n g e s a n d O v e n s 817

panel, and turn on the gas supply to the appliance. Test for any gas leaks. Then turn

on the electricity, test the operation, and adjust the burner flame if needed. For

additional information, see Chapter 6. On electronic models, make sure to take the

range/oven out of the service test mode when the repair is completed.

Ignitor Switch

The ignitor switches (four) are wired in parallel and mounted on each burner valve stem.

These switches are rotary-actuated (Figure 23-7). The ignitor switches control the 120 volt

supply voltage to the spark module by opening and closing the circuit.

The typical complaints associated with the ignitor switch are:

The ignitor switch is hard to turn on.

The surface burner will not light.

Unusual display readouts and/or error codes.

Remove screws

that secure the

front panel

Remove the

screw to remove

the burner

Orifice

Burner knob

Thermostat

capillary tubing

Pressure regulator valve

FIGURE 23-14 A top view of the components in an electronic ignition system.

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Mounting screw

Rubber washer

Orifice

Gas manifold

pipe

Rubber washer

Gas valve housing

Gas “on” position

Gas control seat

Gas

openings

Spring

Detent collar

Stem housing

Screw

Stem

FIGURE 23-15

An exploded view of

the surface burner

valve.

FIGURE 23-16

To remove the surface

burner, remove the

screw that secures

the burner to the

burner bar, and then

lift the burner head up

and out of the range.

Burner head

Venturi

Air shutter

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C h a p t e r 2 3 : G a s R a n g e s a n d O v e n s 819

To handle these problems, perform the following steps:

1. Verify the complaint. Verify the complaint by turning on the surface burners.

Do any of the burners come on? Do you hear or see the ignitors sparking? Are the

ignitor electrodes clear of debris? Is there good contact between the ignitor bracket

and the burner bar? On electronic models, turn off the electricity to the appliance

and wait for two minutes before turning it back on. If a fault code appears, look up

the code. If the range/oven will not power up, locate the technical data sheet

behind the control panel or for diagnostics information. On some models you will

need the actual service manual for the model you are working on to properly

diagnose the range/oven. The service manual will assist you in properly placing

the range/oven in the service test mode for testing the range/oven functions.

2. Check for external factors. You must check for external factors not associated with the

appliance. Is the appliance installed properly? Are there 120 volts to the appliance?

The voltage at the receptacle is between 108 volts and 132 volts during a load on the

circuit. Do you have the correct polarity? (See Chapter 6.)

3. Disconnect the electricity. Before working on the range or cooktop, disconnect the

electricity to the appliance. This can be done by pulling the plug from the receptacle.

Or disconnect the electricity at the fuse panel or at the circuit breaker panel. Turn off

the electricity.

WARNING Some diagnostic tests will require you to test the components with the power turned on.

When you disassemble the control panel, you can position it in such a way that the wiring will

not make contact with metal. This act will allow you to test the components without electrical

mishaps.

Natural gas position

(a)

Cap orifice

Gas flow

Gas flow

Cap

Insert

LP position

(b)

Cap rests against

LP insert Gas from

LP insert

LP insert

Gas through

cap is blocked

FIGURE 23-17 (a) The universal oriice in the natural gas position. (b) The universal oriice in the LP position.

820 P a r t V I : A p p l i a n c e S e r v i c e , I n s t a l l a t i o n , a n d P r e v e n t i v e M a i n t e n a n c e P r o c e d u r e s

4. Shut off the gas supply. Before you begin servicing any gas components, shut off

the supply of gas to the appliance. The shutoff valve should be within six feet of the

gas appliance.

5. Gain access to the ignitor switch. To gain access to the ignitor switch, lift the

cooktop, pull off the control knobs, and then remove the screws from the front panel

(see Figures 23-7 and 23-14). Remove the control panel to expose the ignitor switches.

6. Test the ignitor switch. Remove the wires from the ignitor switch terminals. Set

your ohmmeter to the R × 1 scale; reinstall the surface burner knob on the gas valve.

Place the ohmmeter probes on the ignitor switch terminals. With the burner knob in

the “off” position, the ohmmeter should read no continuity. Turn the burner knob to

the “lite” position; the ohmmeter should read continuity. If your readings differ,

replace the ignitor switch.

7. Install a new ignitor switch. To install a new ignitor switch, remove the screws that

secure the ignitor switch, reverse the disassembly procedure, and reassemble. Turn

on the electricity and the gas supply, and test the surface burner. On some models, the

ignitor will produce between two and three sparks per second. On electronic models,

make sure to take the range/oven out of the service test mode when the repair is

completed.

Surface Burner Ignitor

A surface burner ignitor is a metal rod with a ceramic insulating body that is wired to a

spark module. Electrical pulses from the spark module cause the surface burner ignitor to

arc to the ground strap, which is mounted above the ignitor. These sparks will ignite the

surface burner. On a gas range there are two ignitors to light the four surface burners.

The typical complaints associated with the surface burner ignitor are:

The surface burner will not light.

Only one surface burner ignitor is working.

Intermittent operation of the surface burner ignitor.

Unusual display readouts and/or error codes.

To handle these problems, perform the following steps:

1. Verify the complaint. Verify the complaint by turning on the surface burners. Do

the burners come on? Do you hear or see the ignitors sparking? Are the ignitor

electrodes clear of debris? Is there a good ground contact between the ignitor

bracket and the burner bar? If all of the ignitors are sparking, check for a shorted

ignitor switch. On electronic models, turn off the electricity to the appliance and

wait for two minutes before turning it back on. If a fault code appears, look up the

code. If the range/oven will not power up, locate the technical data sheet behind

the control panel or for diagnostics information. On some models you will need the

actual service manual for the model you are working on to properly diagnose the

range/oven. The service manual will assist you in properly placing the range/oven

in the service test mode for testing the range/oven functions.

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C h a p t e r 2 3 : G a s R a n g e s a n d O v e n s 821

2. Check for external factors. You must check for external factors not associated with the

appliance. Is the appliance installed properly? Are there 120 volts to the appliance?

The voltage at the receptacle is between 108 volts and 132 volts during a load on the

circuit. Do you have the correct polarity? (See Chapter 6.)

3. Disconnect the electricity. Before working on the range or cooktop, disconnect the

electricity to the appliance. This can be done by pulling the plug from the receptacle.

Or disconnect the electricity at the fuse panel or the circuit breaker panel. Turn off

the electricity.

WARNING Some diagnostic tests will require you to test the components with the power turned on.

When you disassemble the control panel, you can position it in such a way that the wiring will

not make contact with metal. This act will allow you to test the components without electrical

mishaps.

4. Shut off the gas supply. Before you begin servicing any gas components, shut off

the supply of gas to the appliance. The shutoff valve should be within six feet of the

gas appliance.

5. Gain access to the ignitor. To gain access to the ignitor (see Figure 23-8), lift up the

cooktop (see Figure 23-14). The ignitor is located on the burner bar, between the two

burners’ flash tubes.

6. Test the ignitor. Set your ohmmeter on R × 100. Test the ignitor bracket to ground;

the meter should indicate continuity. Disconnect the ignitor electrode wire and test

for continuity.

7. Install a new ignitor. Remove the screws that secure the ignitor bracket to the

burner bar, and disconnect the ignitor electrode wire. To reinstall the ignitor, just

reverse the disassembly procedure, and reassemble. Test for a good ground between

the ignitor bracket and the burner bar. Turn on the electricity and the gas supply,

and test the surface burners. The ignitor should produce two sparks per second or,

on some models, two to three sparks per second. On electronic models, make sure

to take the range/oven out of the service test mode when the repair is completed.

Spark Module

The spark module is located in the rear of the range or underneath the cooktop on a cooktop

model. Whenever the spark module is energized by the ignitor switches through an ignitor

cable, a solid-state circuit and pulse transformer within the module housing will send

electronic pulses to both surface ignitors at the same time. The spark module operates at

very low amperage (4 milliamps). The high-voltage pulses or sparks present no severe

shock hazard to the consumer or to the service technician.

The typical complaints associated with the spark module are:

You hear a “clicking” noise but the surface burner will not light.

You hear an erratic “clicking” noise from the surface burner ignitor.

You do not hear the “clicking” noise and the surface burner will not light.

Unusual display readouts and/or error codes.

822 P a r t V I : A p p l i a n c e S e r v i c e , I n s t a l l a t i o n , a n d P r e v e n t i v e M a i n t e n a n c e P r o c e d u r e s

To handle these problems, perform the following steps:

1. Verify the complaint. Verify the complaint by turning on the surface burners.

Do the burners come on? Do you hear or see the ignitors sparking? Are the ignitor

electrodes clear of debris? Is there good contact between the ignitor bracket and the

burner bar?. On electronic models, turn off the electricity to the appliance and wait

for two minutes before turning it back on. If a fault code appears, look up the code.

If the range/oven will not power up, locate the technical data sheet behind the control

panel or for diagnostics information. On some models you will need the actual service

manual for the model you are working on to properly diagnose the range/oven. The

service manual will assist you in properly placing the range/oven in the service test

mode for testing the range/oven functions.

2. Check for external factors. You must check for external factors not associated with the

appliance. Is the appliance installed properly? Are there 120 volts to the appliance?

Does the electrical outlet have the correct polarity? The voltage at the receptacle is

between 108 volts and 132 volts during a load on the circuit. Do you have the

correct polarity? (See Chapter 6.) Is the gas to the appliance turned on?

3. Disconnect the electricity. Before working on the range/oven or cooktop,

disconnect the electricity to the appliance. This can be done by pulling the plug

from the receptacle. Or disconnect the electricity at the fuse panel or at the circuit

breaker panel. Turn off the electricity.

WARNING Some diagnostic tests will require you to test the components with the power turned on.

When you disassemble the control panel, you can position it in such a way that the wiring will

not make contact with metal. This act will allow you to test the components without electrical

mishaps.

4. Shut off the gas supply. Before you begin servicing any gas components, shut off

the supply of gas to the appliance. The shutoff valve should be within six feet of the

gas appliance.

5. Gain access to the spark module. You can access the component by removing the

back panel (see Figure 22-9). Locate the spark module (see Figure 23-8).

6. Test the spark module. Before you test the spark module, test the surface burner

igniter electrodes and the surface burner igniter switches first. Next, check the

grounding strap on the ignitor. Now, check the ignition system wiring for a short or

loose wiring. If they test okay, proceed to test the spark module (Figures 23-8 and

23-18). Set your voltmeter on the 120-volt scale. Remove the L1 wire from the spark

module, and attach one of the meter probes to that wire. Attach the other meter

probe to the neutral terminal on the spark module. Next, turn on the electricity to

the appliance, turn on the surface burner control knob to the “lite” position, and test

for 120 volts. The voltmeter should read 120 volts. If it does not, check the wiring

connections and wiring. After checking the wiring and connections, if you still do

not have the ignitors sparking, then replace the spark module.

PART VI

C h a p t e r 2 3 : G a s R a n g e s a n d O v e n s 823

7. Remove the spark module. With the electricity turned off, disconnect the wiring

terminals from the spark module one at a time and label them. Remove the screws

that secure the spark module to the appliance.

8. Install a new spark module. To install the new spark module, just reverse the

disassembly procedure, and reassemble. Be sure that you install the wires onto the

correct terminals according to the wiring diagram for the product you are servicing.

Turn on the electricity and gas supply, and test the surface burners. Make sure that

the spark at the ignitor has a sharp blue appearance. This indicates a good working

ignition system. On electronic models, make sure to take the range/oven out of the

service test mode when the repair is completed.

L1 N

w

T w

w

w

BK

BK

BK

BK

P1-1 P1-3

Timer

Oven LT.

Panel LT SW.

Door SW.

Oven therm

Surface burner

ignition switches

Sealed burner

units equipped

with 4 ignitors,

open burner units

with 2

Spark module

Bake valve

R R

Bake ignitor

GND

FIGURE 23-18 A typical wiring schematic for a range with electronic ignition.

824 P a r t V I : A p p l i a n c e S e r v i c e , I n s t a l l a t i o n , a n d P r e v e n t i v e M a i n t e n a n c e P r o c e d u r e s

Glow-Bar Ignitor

The glow-bar ignitor is constructed of a silicon-carbide material. When 120 volts is applied

to the glow-bar, it heats up to about 2000 degrees F. As the temperature increases, its

resistance decreases, allowing 2.5 to 4.0 amps to flow to the safety valve.

The typical complaints associated with the glow-bar ignitor are:

The oven/broiler will not light.

The glow-bar ignitor is on but, the oven/broiler burner will not ignite.

Unusual display readouts and/or error codes.

To handle these problems, perform the following steps:

1. Verify the complaint. Verify the complaint by turning on the oven. Does the glowbar

ignitor turn an orange-red color? On electronic models, turn off the electricity to

the appliance and wait for two minutes before turning it back on. If a fault code

appears, look up the code. If the range/oven will not power up, locate the technical

data sheet behind the control panel or for diagnostics information. On some models

you will need the actual service manual for the model you are working on to

properly diagnose the range/oven. The service manual will assist you in properly

placing the range/oven in the service test mode for testing the range/oven

functions.

2. Check for external factors. You must check for external factors not associated with

the appliance. Is the appliance installed properly? Are there 120 volts to the

appliance? The voltage at the receptacle is between 108 volts and 132 volts during a

load on the circuit. Do you have the correct polarity? (See Chapter 6.) Is the gas to

the appliance turned on?

3. Disconnect the electricity. Before working on the range, oven, or cooktop, disconnect

the electricity to the appliance. This can be done by pulling the plug from the

receptacle. Or disconnect the electricity at the fuse panel or at the circuit breaker

panel. Turn off the electricity.

WARNING Some diagnostic tests will require you to test the components with the power turned on.

When you disassemble the control panel, you can position it in such a way that the wiring will

not make contact with metal. This act will allow you to test the components without electrical

mishaps.

4. Shut off the gas supply. Before you begin servicing any gas components, shut off

the supply of gas to the appliance. The shutoff valve should be within six feet of the

gas appliance.

5. Gain access to the glow-bar ignitor. To gain access to the glow-bar ignitor (see

Figures 23-11 and 23-13), open the oven door, remove the oven racks, and remove the

oven floor panel. Next, remove the nut (Figure 23-19) from the oven burner baffle, and

remove the baffle. You now have access to all of the components shown in Figure 23-19.

PART VI

C h a p t e r 2 3 : G a s R a n g e s a n d O v e n s 825

Retaining nut

Oven burner baffle

Oven burner

Gas supply shutoff valve

Gas pressure regulator valve

Safety valve

Safety valve bracket

Glow-bar ignitor

FIGURE 23-19 An exploded view of the components that make up the oven burner system.

826 P a r t V I : A p p l i a n c e S e r v i c e , I n s t a l l a t i o n , a n d P r e v e n t i v e M a i n t e n a n c e P r o c e d u r e s

6. Test the glow-bar ignitor. Disconnect the glow-bar ignitor wires from the wiring

harness. Set your ohmmeter on the R × 100 scale, and check for continuity at the

glow-bar ignitor wire terminals. Read the meter scale—at room temperature of

75 degrees F, the resistance of the glow-bar ignitor should between 50 and 1100 ohms.

If it is under 50 or over 1200 ohms, replace the ignitor. If you are testing the glow-bar

ignitor for amperage and it’s below 2.5 amps, replace it.

7. Remove the glow-bar ignitor. To remove the ignitor, remove the screws that secure

the glow-bar ignitor to the oven burner (see Figures 23-11, 23-13, and 23-19).

8. Install the new glow-bar ignitor. To install the new glow-bar ignitor, just reverse

the disassembly procedure, and reassemble. Be careful—do not touch the silicon

carbide bar within the metal enclosure. If you do, it will create a hot spot on

the silicon carbide bar (from body oils), and the ignitor might burn out. Turn on the

electric and gas supply, and test the glow-bar ignitor. On electronic models, make

sure to take the range/oven out of the service test mode when the repair is

completed.

Pressure Regulator Valve

This mechanical device will perform two functions: it will reduce the higher incoming gas

pressure to a desired lower pressure, and it will maintain a steady and an even flow of gas

through the regulator valve. This valve is located in the bottom rear of the range or it can be

located under the cooktop in the left or right rear.

The typical complaints associated with the pressure regulator valve are:

The oven/broiler burner will not ignite. No gas is supplied to the burner.

Erratic oven/broiler burner flame. The flame will fluctuate between high and low.

Unusual display readouts and/or error codes.

To handle these problems, perform the following steps:

1. Verify the complaint. Verify the complaint by turning on the appliance. Do the

surface burners come on? Are the burner flames small and blue in color? Did you

check the gas pressure at the gas supply line, surface burners, and the oven burner?

Do the burner flames fluctuate in size? Is the pilot light staying lit? Is there a gas

smell near the pressure regulator valve? On electronic models, turn off the electricity

to the appliance and wait for two minutes before turning it back on. If a fault code

appears, look up the code. If the range/oven will not power up, locate the technical

data sheet behind the control panel or for diagnostics information. On some models

you will need the actual service manual for the model you are working on to properly

diagnose the range/oven. The service manual will assist you in properly placing the

range/oven in the service test mode for testing the range/oven functions.

2. Check for external factors. You must check for external factors not associated with

the appliance. Is the appliance installed properly? Are there 120 volts to the appliance?

The voltage at the receptacle is between 108 volts and 132 volts during a load on the

circuit. Do you have the correct polarity? (See Chapter 6.) Is the gas to the appliance

turned on?

PART VI

C h a p t e r 2 3 : G a s R a n g e s a n d O v e n s 827

3. Disconnect the electricity. Before working on the range or cooktop, disconnect the

electricity to the appliance. This can be done by pulling the plug from the receptacle.

Or disconnect the electricity at the fuse panel or at the circuit breaker panel. Turn off

the electricity.

WARNING Some diagnostic tests will require you to test the components with the power turned on.

When you disassemble the control panel, you can position it in such a way that the wiring will not

make contact with metal. This act will allow you to test the components without electrical mishaps.

4. Shut off the gas supply. Before you begin servicing any gas components, shut off

the supply of gas to the appliance. The shutoff valve should be within six feet of the

gas appliance.

5. Gain access to the pressure regulator valve. Locate the pressure regulator valve.

On some models, lift the cooktop or gain access through the oven cavity (see

Figures 23-3, 23-11, 23-14, and 23-19).

6. Test the pressure regulator. The pressure regulator valve is a non-serviceable

component. If you suspect a problem with the regulator, test the gas pressures

with a manometer or a magnehelic gauge (see Figures 8-22 and 8-24). Test the gas

pressure at the supply line before the pressure regulator valve and at the surface

burner orifices. On some models using natural gas, the reading will be between a

four- and six-inch water column. For LP models, the pressure will be between a

nine- and eleven-inch water column. Next, test the gas pressure from the burner

orifice and turn on all the burners; the pressure should remain constant. If the

readings are not within the ranges mentioned, replace the pressure regulator.

7. Remove the gas pressure regulator valve. To remove the gas pressure valve (see

Figure 23-14), pull out the range from the wall and lift up the cooktop. Disconnect

the gas supply line from the range. Remove the gas line from the intake side of the

regulator. Remove the surface burners, pull off the control knobs, and then remove

the screws from the front panel (see Figure 23-14). This will expose the gas burner

valves, thermostat, and manifold. Next, remove the thermostat from the manifold.

If the model you are servicing has electronic ignition, remove the wires from the

ignitor switches and label them. Finally, remove the screws that secure the manifold

to the range. Figure 8-20 shows an exploded view of the gas components. Remove

the manifold with the pressure regulator. Be careful—do not damage the capillary

tube in the thermostat. To remove the gas pressure regulator valve (see Figures 23-11,

23-13, and 23-19), disconnect the gas line to the regulator. Remove the oven burner

and ignitor. Next, remove the screws that secure the safety valve bracket to the

range, and remove the safety valve with the regulator attached.

8. Install the new gas pressure regulator. To install the gas pressure regulator, just

reverse the disassembly procedure, and reassemble. Make sure that you use

approved pipe joint compound or yellow Teflon tape on the pipe connections

(according to local codes) and on the threads of the pressure regulator valve before

you install the valve in the range. Turn on the gas supply to the range. Check for

gas leaks by using a chloride-free soap solution. Do not use a flame to check for gas

leaks. The soap solution will begin to bubble if a leak is present. Turn on the electric

and test the range operation. On electronic models , make sure to take the range/

oven out of the service test mode when the repair is completed.

828 P a r t V I : A p p l i a n c e S e r v i c e , I n s t a l l a t i o n , a n d P r e v e n t i v e M a i n t e n a n c e P r o c e d u r e s

Safety Valve

The safety valve is located in the bottom at the rear of the range or oven (Figures 23-5 and

23-11). The electric safety valve is wired in series with the ignitor or glow-bar. The safety

valve will only open to allow gas to flow to the burner when there is enough current (2.5 to

4 amps) to cause the bimetal-controlled diaphragm within the valve body to warp open and

allow the gas to flow through the safety valve to the burner.

The typical complaints associated with the safety valve are:

The oven/broiler burner will not ignite. No gas is supplied to the burner.

Broken capillary tube.

Unusual display readouts and/or error codes.

To handle these problems, perform the following steps:

1. Verify the complaint. Verify the complaint by turning on the appliance. Does the

oven or broil burner come on? On electronic models, turn off the electricity to the

appliance and wait for two minutes before turning it back on. If a fault code appears,

look up the code. If the range/oven will not power up, locate the technical data sheet

behind the control panel or for diagnostics information. On some models you will

need the actual service manual for the model you are working on to properly

diagnose the range/oven. The service manual will assist you in properly placing the

range/oven in the service test mode for testing the range/oven functions.

2. Check for external factors. You must check for external factors not associated with

the appliance. Is the appliance installed properly? Are there 120 volts to the

appliance? The voltage at the receptacle is between 108 volts and 132 volts during a

load on the circuit. Do you have the correct polarity? (See Chapter 6.) Is the gas to

the appliance turned on?

3. Disconnect the electricity. Before working on the range or cooktop, disconnect the

electricity to the appliance. This can be done by pulling the plug from the receptacle.

Or disconnect the electricity at the fuse panel or at the circuit breaker panel. Turn off

the electricity.

WARNING Some diagnostic tests will require you to test the components with the power turned on.

When you disassemble the control panel, you can position it in such a way that the wiring will not

make contact with metal. This act will allow you to test the components without electrical mishaps.

4. Shut off the gas supply. Before you begin servicing any gas components, shut off

the supply of gas to the appliance. The shutoff valve should be within six feet of the

gas appliance.

5. Gain access to the safety valve. To gain access to the safety valve (see Figure 23-20),

open the oven door, remove the oven racks, and remove the oven floor panel. Next,

remove the nut (see Figure 23-19) from the oven burner baffle, and remove the

baffle. You now have access to all of the components shown in Figure 23-19.

PART VI

C h a p t e r 2 3 : G a s R a n g e s a n d O v e n s 829

Heater sensing

bulb and capillary tube

Orifice hood

Gas inlet

Standing pilot safety valve

(a)

Terminals

Combination bake/broil

gas safety valve

(b)

Broil terminals

Dual gas safety valve

(c)

Bake

terminals

FIGURE 23-20 (a) A standing pilot safety valve. (b) A combination bake/broil safety valve. (c) A dual gas

safety valve with the pressure regulator attached.

830 P a r t V I : A p p l i a n c e S e r v i c e , I n s t a l l a t i o n , a n d P r e v e n t i v e M a i n t e n a n c e P r o c e d u r e s

6. Test the safety valve. The standing pilot safety valve cannot be tested: it is a

temperature-controlled device. If you notice that the capillary tube is broken,

replace the safety valve. Other models use an electrically controlled safety valve

(bimetal operated). To test this type of valve (see Figure 23-20), set your ohmmeter to

the R × 1 scale. Disconnect the wires from the valve terminals, and touch the ohmmeter

probes to the terminals. The reading should be between 1 and 5 ohms. If your meter

reads an open circuit or high resistance, the safety valve will have to be replaced.

7. Remove the safety valve. To remove the gas safety valve (see Figures 23-11, 23-13,

and 23-19), disconnect the gas line to the regulator. Remove the oven burner and

ignitor. Next, remove the screws that secure the safety valve bracket to the range,

and remove the safety valve with the regulator attached.

8. Install the new safety valve. To install the safety valve, just reverse the disassembly

procedure, and reassemble. Make sure that you use approved pipe joint compound

or yellow Teflon tape on the pipe connections (according to local codes) and on the

threads of the pressure regulator valve and the safety valve before you install the

valve(s) in the range. Turn on the gas supply to the range. Check for gas leaks by

using a chloride-free soap solution. Do not use a flame to check for gas leaks. The soap

solution will begin to bubble if a leak is present. Turn on the electric and test the

operation of the range/oven. On electronic models, make sure to take the range/

oven out of the service test mode when the repair is completed.

Electronic Control Board and User Interface Controls

The electronic control board and the user interface controls operate the bake, broil, time

bake, and the self-clean functions of the range or oven. The electronic control board also

displays the time of day, timer, and any error or fault codes. The electronic control board

and the user interface controls are located in the control panel.

The typical complaints associated with the electronic control board or the user interface

controls are:

The range or oven won’t run or power up.

Unable to program the range or oven.

The display board will not display anything.

One or more key pads will not accept commands.

Unusual display readouts and/or error codes.

To prevent electrostatic discharge (ESD) from damaging expensive electronic

components, follow the steps in Chapter 11.

To handle these problems, perform the following steps:

1. Verify the complaint. Verify the complaint by operating the range or oven. Turn off

the electricity to the appliance and wait for two minutes before turning it back on. On

electronic models, turn off the electricity to the appliance and wait for two minutes

before turning it back on. If a fault code appears, look up the code. If the range/oven

will not power up, locate the technical data sheet behind the control panel or for

diagnostics information. On some models you will need the actual service manual

for the model you are working on to properly diagnose the range/oven. The service

PART VI

C h a p t e r 2 3 : G a s R a n g e s a n d O v e n s 831

manual will assist you in properly placing the range/oven in the service test mode for

testing the range/oven functions.

2. Check for external factors. You must check for external factors not associated with

the appliance. Are there 120 volts of electricity to the range or oven? The voltage at

the receptacle is between 108 volts and 132 volts during a load on the circuit. Do

you have the correct polarity? (See Chapter 6.)

3. Disconnect the electricity. Before working on the range or oven, disconnect the

electricity. This can be done by pulling the plug out of the wall receptacle. Or disconnect

the electricity at the fuse panel or circuit breaker panel. Turn off the electricity.

WARNING Some diagnostic tests will require you to test the components with the power turned on.

When you disassemble the control panel, you can position the panel in such a way that the

wiring will not make contact with metal. This will allow you to test the components without

electrical mishaps.

4. Shut off the gas supply. Before you begin servicing any gas components, shut off

the supply of gas to the appliance. The shutoff valve should be within six feet of the

gas appliance.

5. Remove the console panel to gain access. You can access the electronic control

board (some models have multiple circuit boards) by removing the back panel (see

Figure 22-9) on a freestanding range. On models with front-mounted controls (see

Figure 22-10), the panel is attached with screws on both ends. Remove the screws,

and tilt the control panel. Be careful not to let the wires come off their components.

Some built-in models have a removable backsplash (see Figure 22-11); just lift the

backsplash and rest it on the cooktop. It would be a good idea to place something

on the cooktop first to protect it from damage. Next, remove the screws from the

backsplash that hold the rear panel to gain access to the electronic control board. If

you are repairing a wall oven or an eye-level range, the control panel can be removed

(see Figure 22-12) by opening the door and removing the screws that secure the

panel. These might be underneath the front of the exhaust hood or just below the

control panel. Some control panels are hinged; just tilt the control panel toward you

for servicing. On other models, to gain access to the electronic control board, both

the rear panel and the front control panel (usually glass) will have to be removed.

Remove the screws that secure the trim piece that holds the glass in place.

6. Test the electronic control board and user interface control. If you are able to run

the range/oven diagnostic test mode, check the different functions. Use the technical

data sheet for the model you are servicing to locate the test points on the wiring

schematic. Check all wiring connections and wiring. Using the technical data sheet,

test the electronic control or user interface controls, input voltages, and output

voltages. On some models, fuses are soldered to the printed circuit board (PCB).

These fuses must be tested first before condemning the component.

7. Remove the electronic control board or user interface control. To remove the

defective component, remove the screws that secure the boards to the control panel

or range/oven frame. Disconnect the connectors from the electronic control board

or user interface control.

832 P a r t V I : A p p l i a n c e S e r v i c e , I n s t a l l a t i o n , a n d P r e v e n t i v e M a i n t e n a n c e P r o c e d u r e s

8. Install the new component. To install a new electronic control board or user interface

control, read the part installation literature that came with the part and just reverse

the disassembly procedure, and reassemble. Reinstall the console panel, and restore

the electricity and gas supply to the range/oven. Test the range/oven operation.

On electronic models, make sure to take the range/oven out of the service test mode

when the repair is completed.

Oven Temperature Sensor

The oven temperature sensor (Figure 22-36) is a thermistor. The thermistor is a thermally

sensitive resistor that exhibits a change in electrical resistance with a change in its temperature.

The oven temperature sensor is located in the upper left or right attached to the rear wall of the

oven cavity. The oven temperature sensor sends the resistance readings to the electronic oven

control board. The electronic control board monitors the resistance readings of the oven

temperature sensor and turns the bake or broil on or off at the desired temperature.

The typical complaints associated with the oven temperature sensor are:

Erratic temperature in the oven cavity.

The oven/broiler burner will not ignite.

Unusual display readouts and/or error codes.

To handle these problems, perform the following steps:

1. Verify the complaint. Verify the complaint by turning on the appliance. Does the oven

operate? Test the oven temperature. On electronic models, turn off the electricity to the

appliance and wait for two minutes before turning it back on. If a fault code appears,

look up the code. If the range/oven will not power up, locate the technical data sheet

behind the control panel or for diagnostics information. On some models you will

need the actual service manual for the model you are working on to properly diagnose

the range/oven. The service manual will assist you in properly placing the range/

oven in the service test mode for testing the range/oven functions.

2. Check for external factors. You must check for external factors not associated with

the appliance. Is the appliance installed properly? Are there 120 volts to the appliance?

The voltage at the receptacle is between 108 volts and 132 volts during a load on the

circuit. Do you have the correct polarity? (See Chapter 6.) Is the gas to the appliance

turned on?

3. Disconnect the electricity. Before working on the range or cooktop, disconnect the

electricity to the appliance. This can be done by pulling the plug from the receptacle.

Or disconnect the electricity at the fuse panel or at the circuit breaker panel. Turn off

the electricity.

WARNING Some diagnostic tests will require you to test the components with the power turned on.

When you disassemble the control panel, you can position it in such a way that the wiring will not

make contact with metal. This act will allow you to test the components without electrical mishaps.

4. Shut off the gas supply. Before you begin servicing any gas components, shut off

the supply of gas to the appliance. The shutoff valve should be within six feet of the

gas appliance.

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C h a p t e r 2 3 : G a s R a n g e s a n d O v e n s 833

5. Gain access to the oven temperature sensor. To gain access, open the oven door.

The temperature sensor is located in the upper corners of the oven cavity.

6. Remove the oven temperature sensor. Remove the oven racks. Remove the two

screws that secure the sensor to the oven cavity wall. Pull the sensor toward you

gently, disconnect the connector, and remove the temperature sensor from the oven.

There may be times when the connector will not pass through the hole in the oven

cavity. If this is the case, then you will have to access the connector from the rear of

the range/oven. On some models, to access the temperature sensor, you will have

to remove the temperature sensor from the rear of the range/oven by removing the

screws that secure the sensor to the oven cavity in the rear of the range/oven.

7. Test the oven temperature sensor. Set your ohmmeter on the R × 10 scale, and

measure the resistance between the two pin connectors on the sensor wire connector.

For most sensors, the meter reading at room temperature should match the chart in

Figure 23-21. For example: If the room temperature is approximately 75 degrees

Fahrenheit, the resistance in the sensor will be 1100 ohms. If the reading is less than

1000 ohms, replace the sensor. If the reading is above 1100 ohms at 75 degrees,

replace the sensor.

8. Install the new oven temperature sensor. To install the oven temperature sensor,

just reverse the disassembly procedure, and reassemble. Turn on the electric and the

gas supply and test the oven temperature. On electronic models, make sure to take

the range/oven out of the service test mode when the repair is completed. With an

oven temperature tester, place the thermocouple tip in the center of the oven cavity.

Be sure that the thermocouple tip does not touch any metal. Close the oven door,

set the oven to bake, and adjust the thermostat setting to the 350-degree mark.

Let the oven cycle for 20 to 30 minutes. Then record the minimum and maximum

Oven temperature

sensor

Connector

Temperature (°F)

32

75

250

350

450

550

650

900

1000

1100

1450

1650

1850

2050

2230

2700

Resistance ()

FIGURE 23-21

A typical oven

temperature sensor.

This type of sensor is

only used in ranges

and ovens with

electronic controls.

834 P a r t V I : A p p l i a n c e S e r v i c e , I n s t a l l a t i o n , a n d P r e v e n t i v e M a i n t e n a n c e P r o c e d u r e s

temperatures of three cycles. Next, add these temperatures, and divide by 6. This

will give you the average temperature of the oven:

370 + 335 + 350 + 340 + 360 + 335

= 348.3 degrees Fahrenheit

6

The average temperature calculated should be within ±5 degrees of the temperature

setting selected. Oven temperature sensors (RTDs) are used with electronically controlled

ovens. To make any temperature adjustments in the electronic control, the technician needs

to locate the technical data sheet. This sheet will show you how to make the temperature

adjustments for the model you are servicing.

Thermostat (Standing Pilot)

The oven thermostat is located in the control panel and it is mounted on the manifold pipe.

The thermostat is a hydraulic valve that has two separate gas lines and a sensing bulb

(Figure 23-5). The pilot gas line maintains a pilot flame in the oven, and the main gas line

provides gas to the safety gas valve. The sensing bulb is a mercury-filled tube attached to a

capillary tube that controls the thermostat to open or close the gas supply to the oven burner.

The thermostat operates on temperature change it senses from within the oven cavity.

The typical complaints associated with the thermostat are:

The oven/broiler burner will not come on.

Erratic oven cavity temperatures.

To handle these problems, perform the following steps:

1. Verify the complaint. Verify the complaint by turning on the appliance. Does the

oven operate? Test the oven temperature.

2. Check for external factors. You must check for external factors not associated with

the appliance. Is the appliance installed properly? Are there 120 volts to the appliance?

The voltage at the receptacle is between 108 volts and 132 volts during a load on the

circuit. Do you have the correct polarity? (See Chapter 6.) Is the gas to the appliance

turned on?

3. Disconnect the electricity. Before working on the range or cooktop, disconnect the

electricity to the appliance. This can be done by pulling the plug from the receptacle.

Or disconnect the electricity at the fuse panel or at the circuit breaker panel. Turn off

the electricity.

WARNING Some diagnostic tests will require you to test the components with the power turned on.

When you disassemble the control panel, you can position it in such a way that the wiring will not

make contact with metal. This act will allow you to test the components without electrical mishaps.

4. Shut off the gas supply. Before you begin servicing any gas components, shut off

the supply of gas to the appliance. The shutoff valve should be within six feet of the

gas appliance.

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C h a p t e r 2 3 : G a s R a n g e s a n d O v e n s 835

5. Gain access to the oven thermostat. To gain access to the oven thermostat, lift up

the cooktop, pull off the control knobs, and then remove the screws from the front

panel (see Figure 23-14). Remove the control panel. This will expose the gas burner

valves, thermostat, and manifold (see Figures 8-20 and 23-5).

6. Remove the thermostat. Before removing the thermostat, remove the capillary

tube and sensor from the oven cavity. The sensing bulb will be attached by two

retaining clips. Squeeze the clips, pull away from the oven cavity, and remove the

sensing bulb and capillary tubing. Feed the capillary tubing through the oven

cavity to the top of the range. Disconnect the main gas line and the pilot gas line

from the thermostat. Then remove the screws that secure the thermostat to the

manifold (see Figures 8-20 and 23-5).

7. Install the new thermostat. To install the thermostat, just reverse the disassembly

procedure, and reassemble. Make sure that you use approved pipe joint compound

or yellow Teflon tape on the pipe connections (according to local codes) and on the

threads of the gas lines (if needed) before you install the thermostat on the manifold.

Turn on the gas supply to the range. Check for gas leaks by using a chloride-free

soap solution. Do not use a flame to check for gas leaks. The soap solution will begin to

bubble if a leak is present.

8. Test the oven temperature. Turn on the electric and gas supply to the range/oven.

With an oven temperature tester, place the thermocouple tip in the center of the

oven cavity. Be sure that the thermocouple tip does not touch any metal. Close the oven

door, set the oven to bake, and adjust the thermostat setting to the 350-degree mark.

Let the oven cycle for 20 to 30 minutes. Then record the minimum and maximum

temperatures of three cycles. Next, add these temperatures, and divide by 6. This will

give you the average temperature of the oven:

370 + 335 + 350 + 340 + 360 + 335

= 348.3 degrees Fahrenheit

6

The average temperature calculated should be within ±25 degrees of the temperature

setting selected. If not, try calibrating the thermostat. To calibrate the thermostat, pull the

oven thermostat knob off, and look at the thermostat (see inset in Figure 23-22). The slotted

screw on the thermostat is for converting the thermostat for the type of gas supplied to the

range. Set it to the proper setting. If you look into the thermostat stem, you will see a small

adjustment screw. This screw is used for calibrating the thermostat. Turning the screw

slightly to the right will increase the temperature. To decrease the temperature setting, turn

the screw to the left slightly. For every adjustment made, you must test the oven temperature

as stated above.

Range/Oven Time Clock

The range/oven time clock is located in the control panel. The clock runs on 120 volts and

controls the timer, time bake, clean cycle, and shows the time of day. On electronic models

the clock will display error/ fault codes also.

The typical complaints associated with failure of the range/oven time clock are:

Timed bake cycle will not operate.

Unable to use the self-cleaning cycle.

836 P a r t V I : A p p l i a n c e S e r v i c e , I n s t a l l a t i o n , a n d P r e v e n t i v e M a i n t e n a n c e P r o c e d u r e s

Clock loses time.

Clock is not functioning.

The minute reminder is not functioning.

Unusual display readouts and/or error codes.

To handle these problems, perform the following steps:

1. Verify the complaint. Verify the complaint by turning the clock controls to the

correct time. Does the clock time advance? Some models have the minute reminder

located on the same clock. Set this timer to test it. Does it advance? Turn off the

electricity to the appliance and wait for two minutes before turning it back on. If a

fault code appears, look up the code. If the range/oven will not power up, locate

the technical data sheet behind the control panel for the diagnostics information.

On some models you will need the actual service manual for the model you are

working on to properly diagnose the range/oven. The service manual will assist

you in properly placing the range/oven in the service test mode for testing the

range/oven functions.

2. Check for external factors. You must check for external factors not associated with

the appliance. Is the fuse blown? Does the appliance have the correct voltage? The

voltage at the receptacle is between 198 volts and 264 volts during a load on the

circuit (see Chapter 6).

Pilot gas line to the

pilot light assembly

Main gas line

to the manifold

Oven

thermostat

Natural gas

setting

Adjustment

screw

LP gas

setting

Inset

Gas ‘‘OFF”

setting

N

A

T

L

P

OFF

FIGURE 23-22

When converting the

range to the type of

gas that is supplied to

the home, you must

convert the

thermostat as well.

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C h a p t e r 2 3 : G a s R a n g e s a n d O v e n s 837

3. Disconnect the electricity. Before working on the range or oven, disconnect the

electricity to the appliance. This can be done by pulling the plug from the receptacle.

Or disconnect the electricity at the fuse panel or at the circuit breaker panel. Turn off

the electricity.

WARNING Some diagnostic tests will require you to test the components with the power turned on.

When you disassemble the control panel, you can position it in such a way that the wiring will

not make contact with metal. This act will allow you to test the components without electrical

mishaps.

4. Gain access to the range/oven clock. You can access the clock by removing the back

panel (see Figure 22-9) on a freestanding range. On models with front-mounted

controls (see Figure 22-10), the panel is attached with screws on both ends. Remove

the screws, and tilt the control panel. Be careful not to let the wires come off their

components. Some built-in models have a removable backsplash (see Figure 22-11);

just lift the backsplash and rest it on the cooktop. It would be a good idea to place

something on the cooktop first to protect it from damage. Next, remove the screws

from the backsplash that hold the rear panel to gain access to the clock. If you are

repairing a wall oven or an eye-level range, the control panel can be removed (see

Figure 22-12) by opening the door and removing the screws that secure the panel.

These might be underneath the front of the exhaust hood or just below the control

panel. Some control panels are hinged; just tilt the control panel toward you for

servicing. On other models, to gain access to the clock, both the rear panel and the

front control panel (usually glass) will have to be removed. Remove the screws that

secure the trim piece that holds the glass in place. Then remove the trim piece. On

some models, the trim might have to be removed first. Figure 22-40 illustrates the

different types of clock faces available on ranges/ovens.

5. Test the range/oven clock. On some models, if the clock does not run, check for a

fuse in the circuit. Locate the clock motor wire leads, and isolate them from the

circuit (label them). Using the ohmmeter, set the range scale on R × 1. Place the

probes on the clock motor leads; there should be continuity. If not, replace the clock.

On some models, the clock is used to control the timed baking and the self-cleaning

cycles (see Figures 22-40b, 22-40c, and 22-40d). To check the switch mechanism of

the clock, remove the wires from the switch terminals (label them). Using the

ohmmeter, set the range scale on R × 1. Place the probes on the terminals. Look at

the wiring diagram for the correct terminals to test. Some models have one switch;

other models have two sets of switches. Test for continuity of the switch contacts

when you push in and turn the start and stop knobs on the clock and when the

knobs pop out. On electronic control models, refer to the technical data sheet

located in the range for the testing procedure.

6. Remove the range/oven time clock. First remove the clock knobs from the stems.

To remove the range/oven time clock in this model (Figure 22-41), use a screwdriver

and depress the clips that hold the clock to the control panel. On other models, the

clock is secured to the control panel by screws or nuts. Pull the clock toward the

front of the appliance (Figure 22-42).

838 P a r t V I : A p p l i a n c e S e r v i c e , I n s t a l l a t i o n , a n d P r e v e n t i v e M a i n t e n a n c e P r o c e d u r e s

7. Install a new range/oven clock. Transfer the wires from the old clock to the new

clock. Be sure that you install the wires on their correct terminals according to the

wiring diagram. To install the new range/oven clock, just reverse the disassembly

procedure and reassemble. Turn on the electric and gas supply and test the operation

of the product.

Flame Adjustments

There may be times when the surface, oven, or broil burner flame needs to be adjusted. The

proper surface burner flame should be about 5/8 inch high with a well-defined blue flame.

If the gas pressure to the burner is correct, all you have to do is adjust the air shutter on the

surface burner (see Figure 23-16) to obtain the correct size and color. The oven and broil

burners’ flame should be about 3/4 inch high with a well-defined blue flame. With the

correct gas pressure to the burners, all that is needed is to adjust the air shutters on the

burners (Figures 23-13 and 23-23) to obtain the correct size and color. For sealed burner

cooktops, you cannot make any air adjustments.

Diagnostic Charts and Wiring Diagrams

The following diagnostic flowcharts will help you to pinpoint the likely causes of the

various problems associated with gas ranges and ovens (Figures 23-24 and 23-25). The

wiring diagrams in this chapter are examples only. You must refer to the actual wiring

diagram for the range, oven, or cooktop that you are servicing. Figure 23-26 depicts samples

of actual strip circuit diagrams. The strip circuit diagram is simpler and is usually easier to

read. Figures 23-18 and 23-27 depict actual wiring schematic diagrams.

Bake burner

air shutter

FIGURE 23-23

Adjusting the air

shutter on the oven

burner.

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C h a p t e r 2 3 : G a s R a n g e s a n d O v e n s 839

White-blue color flame Too much primary air Adjust the air shutter

Small flame and blue

in color

The burner orifice is

clogged

Clean or replace the

orifice

The venturi throat is

clogged

Clean the venturi

throat or replace the

burner

The gas line is

restricted or clogged

Remove the debris or

replace the gas supply

line

Low gas pressure

Test the gas pressure at

the burner and adjust

the orifice setting

Yellow flame Not enough primary air Adjust the air shutter

Not enough primary

air

Clean the air shutter

and adjust the air-gas

mixture

Wrong size burner

orifice

Replace the orifice

with the correct size

Noisy flame Too much primary air

Clean and adjust the air

shutter and adjust the airgas

mixture

Gas pressure too high

Check gas pressure and

adjust

Orifice noisy

Debris in the orifice or

the wrong size

Clean the orifice or

replace

Too much gas Adjust the gas pressure

FIGURE 23-24 Flowchart identifying the causes of various lame characteristics. (continued)

840 P a r t V I : A p p l i a n c e S e r v i c e , I n s t a l l a t i o n , a n d P r e v e n t i v e M a i n t e n a n c e P r o c e d u r e s

Air intake noise or a

mixing noise

The mixing tube or

venturi has a rough

area

Smooth the interior

surface or replace

the burner

Check the venturi

and mixing tube for

debris

Clean out the mixing

tube or replace

burner

Reinstall the burner

correctly

The burner is not

installed correctly.

Check the orifice

and venturi distance

The flame fluctuates

high and low

Check the gas

pressure regulator

for a flutter

Replace the gas

pressure regulator

Check for a

malfunctioning

control valve

At the control valve,

adjust the regulator

or replace

FIGURE 23-24 Flowchart identifying the causes of various lame characteristics.

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C h a p t e r 2 3 : G a s R a n g e s a n d O v e n s 841

FIGURE 23-25 Diagnostic lowchart: gas odor; unable to light the surface burners; the oven burner will

not light; the self-cleaning feature does not work.

Gas odor Is the pilot light out?

Relight the pilot after you

ventilate the room

Check and see if the

surface burner valve

is on slightly

Turn off the surface

burner valve

Do you smell gas?

Check for a gas leak after

you ventilate the room

Check the electronic

ignitors

Unable to light

the surface

burners

1. Is the pilot light lit?

2. Are the burner ports blocked?

3. Is the surface burner installed correctly?

4. Is the electricity turned on at the range?

5. Is the air-gas mixture correct?

1. Light the pilot.

2. Clean the ports.

3. Reinstall the burner.

4. Check for 120 volts.

5. Check the ignitors.

6. Adjust the air shutter.

7. Check gas pressure regulator.

The oven burner

will not light

Check the pilot light

Light the pilot and check

for proper pilot flame height

Check the control

settings

Adjust the clock timer

Is there electric

power to the range?

Check for 120 volts to the

range (circuit breaker off ?)

Does the glow-bar

ignitor turn red?

Test the glow-bar ignitor

Are the controls set

properly?

Set the controls properly.

Check the T-stat, selector

switch, safety valve, and the

pressure regulator valve.

The self-clean

oven does not

work

1. Are the controls set properly?

2. Will the oven door lock?

3. Test the T-stat and selector switch.

4. Check the door alignment and gasket.

5. Check for 120 volts to the range.

1. Set the controls properly.