HOW
RANGES/STOVES/OVENS WORK
 Electric
combination range/ovens are stoves that have both surface burners and an
oven. Depending on their features, some electric range/oven units are quite
complex. To understand how they work, let's look at the following areas:
The
control panel
The
cooktop
The
area beneath the cooktop
The
interior of the oven
The
broiler
The
back of the unit
|
| The
control panel |
| There
are many variations of range/oven combination units. We'll describe the
following controls and devices, their function, and the interaction they
may have with other components.
Thermostat
Clock
Electronic
keypad
Selector
switch for bake/broil/timed bake, etc.
Light
switches
Surface
burner switches
Self-cleaning
buttons or switches
Convection
oven components |
| Thermostat |
| The
thermostat is right behind the knob you use to set the oven baking temperature.
There's a long, thin copper tube attached to this knob that leads into
the oven compartment. It senses the temperature inside the oven and signals
the thermostat to provide or prevent further heating.
There's
another type of thermostat--an electronic/mechanical hybrid unit--that
has a small electronic circuit board behind the knob. It has a sensor attached
to it--about the size of a 4- to 6-inch pencil, that protrudes into the
oven. When the oven reaches the temperature you set, the sensor signals
the circuit board, which turns off the electric burner(s) in the oven.
|
| Clock |
The
clock is either electronic or mechanical:
-
Electronic
clocks have a lighted, digital readout. These are not usually repairable;
when they fail, you usually need to replace the whole clock.
-
Mechanical
clocks usually have three dials--the clock dial, a Start time dial, and
a Stop time dial. You set the main clock to the time of day. Then, when
you choose a time-bake or self-clean cycle, the clock turns on the oven
at the start time and turns it off at the stop time. The Start and Stop
dials are for both timed baking and self-cleaning.
|
| Electronic
keypad |
| Some
range/ovens have a keypad for setting all of the oven, broiler, timed bake,
and self-cleaning times, and temperatures. These keypads can't be serviced;
you usually need to replace them when a problem arises. |
| Selector
switch for bake/broil/timed bake, etc. |
| Electric
range/ovens have at least one control switch for the oven/broiler. On some
units, this is the same switch as the thermostat, on others it is a separate
switch.
If
it's a separate switch, it works in conjunction with the thermostat. You
set the thermostat to the cooking temperature you want and set the selector
switch to allow Bake, Broil, Timed Bake, and so on.
|
| Light
switches |
| Many
range/ovens have a light inside the oven. Sometimes a switch on the control
panel lets you manually turn the light on. There's also usually a plunger-type
of switch mounted to the frame of the stove that turns on the light when
you open the door. Some units also have a rangetop light with a manual
On/Off switch on the control panel. |
| Surface
burner switches |
| The
surface burner switches are also referred to as "infinite switches." They
work in much the same way as a dimmer switch for a light in your home.
By turning the switch from low to high you are increasing and decreasing
the electrical current flowing through the electric burner thereby adjusting
the temperature of the element. |
| Self-cleaning
buttons or switches |
| In
addition to the clock controls for the self-cleaning feature, there may
also be other related devices--for example, a door lock button or switch,
a separate switch to toggle between self clean and normal bake, etc. Because
self-cleaning ovens differ, we can't explain every possible combination
of devices needed to begin the self-cleaning cycle for your particular
oven. We recommend that you consult your owner's manual for more information. |
| Convection
oven components |
| Convection
ovens use a circulating fan to constantly move the air inside the oven.
This provides a very even cooking temperature throughout the oven. With
the temperature consistent, foods cook more evenly and quickly. Some units
incorporate the heating element into the circulating fan, which prevents
the hot spots that can be caused by an exposed heating element. Other units
put the heating element beneath the oven floor, or integrate it with the
convection fan itself.
Convection
ovens use a selector switch in conjunction with a thermostat, so that you
can turn off the convection feature when you don't want it.
|
| The
cooktop |
| Electric
range/ovens may have coil type burners on their cooktops--the top of the
range/oven. Or the whole cooktop may be what's called a "smoothtop," where
the burners are integrated with the top surface of the unit.
Coil
type burners - The cooktop usually has four to six metal burners (or heating
elements). Each is a coiled sheath with a wire in the center and no moving
parts. When the wire receives electricity, the wire becomes red hot, which
heats the metal sheath by conduction. Then the sheath glows red. You see
this glowing when the element is turned on.
Euro
type burners - Euro burners are solid, smooth, and 6 to 8 inches in diameter.
Each has an internal coil of wire in the center and no moving parts. When
the wire receives electricity, it becomes hot, which heats the solid metal
surface. Although the surface of the burner doesn't glow bright red, it
becomes very hot.
Smoothtop
ranges - The way smoothtop ranges work is similar to the way coil type
burners work. There is a coiled wire beneath each burner area. When electricity
is applied to the wire, it glows red hot. The heat created is conducted
through the glass and either radiated to the pan on the cooktop or conducted
from the glass to the metal of the pan.
Some
smoothtop ranges also have red halogen lights to supplement the coil-type
elements. These get hot immediately, to speed the burner's warm-up time.
|
| The
area beneath the cooktop |
| Many
cooktops with coil burners let you raise the entire cooktop for cleaning
and service. Manufacturers often place the model and serial number tag
for the appliance beneath the cooktop. |
| The
interior of the oven |
| The
racks inside the oven hold the food to be cooked. In most non-convection
ovens, you can see the heating element at the bottom of the oven and the
broiler element at the top. Each element is a coiled metal sheath with
a wire in the center, and no moving parts. When electricity flows to the
wire, the wire becomes red hot and heats the metal sheath by conduction.
The sheath then glows red, which you can see shortly after you turn on
the oven or broiler. |
| The
broiler |
| See
"The interior of the oven." |
| The
back of the unit |
| Much
of the wiring for an electric range/oven is on the back of the appliance.
The steel panels that cover the wiring protect both you and the wiring.
Other components--such as relays, self-cleaning switches, transformers,
and terminal blocks--are also behind the protective back panels. |
|
| Gas
combination range/ovens are stoves that have both surface burners and an
oven. Depending on their features, some gas range/oven units are quite
complex. To understand how they work, let's look at the following areas.
The
control panel
Gas
delivery (burner, oven, and broiler)
The
area beneath the cooktop
The
interior of the oven
The
area behind the broiler drawer
The
back of the unit |
| The
control panel |
| There
are many variations of range/oven combination units. We'll describe the
following controls and devices, their function, and the interaction they
may have with other components.
Thermostat
Clock
Electronic
keypad
Selector
switch for bake/broil/timed bake, etc.
Light
switches
Self-cleaning
buttons or switches |
| Thermostat |
| In
a non-electric oven system, the thermostat is right behind the knob you
use to set the oven baking or broiling temperature. There's a long, thin
copper tube attached to this thermostat that leads into the oven compartment.
It senses the temperature inside the oven and signals the thermostat to
provide or prevent further heating.
There's
another type of thermostat--an electronic/mechanical hybrid unit--that
has a small electronic circuit board behind the knob. It has a sensor attached
to it--about the size of a 4- to 6-inch pencil, that protrudes into the
oven. When the oven reaches the temperature you set, the sensor signals
the circuit board, which turns off the gas burner(s) in the oven.
|
| Clock |
The
clock is either electronic or mechanical:
-
Electronic
clocks have a lighted, digital readout. These are not usually repairable;
when they fail, you usually need to replace the whole clock.
-
Mechanical
clocks usually have three dials--the clock dial, a Start time dial, and
a Stop time dial. You set the main clock to the time of day. Then, when
you choose a time-bake or self-clean cycle, the clock turns on the oven
at the start time and turns it off at the stop time. The Start and Stop
dials are for both timed baking and self-cleaning.
|
| Electronic
keypad |
| Some
range/ovens have a keypad for setting all of the oven, broiler, timed bake,
and self-cleaning times, and temperatures. These keypads can't be serviced;
you usually need to replace them when a problem arises. |
| Selector
switch for bake/broil/timed bake, etc. |
| Gas
range/ovens have at least one control switch for the oven/broiler. On some
units, this is the same switch as the thermostat, on others it is a separate
switch.
If
it's a separate switch, it works in conjunction with the thermostat. You
set the thermostat to the cooking temperature you want and set the selector
switch to allow Bake, Broil, Timed Bake, and so on.
|
| Light
switches |
| Many
range/ovens have a light inside the oven. Sometimes a switch on the control
panel lets you manually turn the light on. There may be a plunger-type
of switch mounted to the frame of the stove that turns on the light when
you open the door. Some units also have a rangetop light with a manual
On/Off switch on the control panel. |
| Self-cleaning
buttons or switches |
| In
addition to the clock controls for the self-cleaning feature, there may
also be other related devices--for example, a door lock button or switch,
a separate switch to toggle between self clean and normal bake, etc. Because
self-cleaning ovens differ, we can't explain every possible combination
of devices needed to begin the self-cleaning cycle for your particular
oven. We recommend that you consult your owner's manual for more information. |
| Gas
delivery (burner, oven, and broiler) |
| All
gas range top burners use a similar system of gas delivery. There's one
control knob for each burner. It's attached to a small gas valve that's
mounted right to a main gas line. As you turn on the valve, the gas flows
through the valve into a "venturi" tube, which mixes the gas with air to
create the proper mix for combustion. The mixture then flows into the burner
itself, where the standing pilot light flame or the igniter ignites it.
You regulate the flame size by adjusting the burner control knob. It restricts
the amount of gas that flows through the valve.
Often
the oven and broiler work in a similar way. The thermostat knob may be
attached to a small gas valve that's mounted right to a main gas line.
As you turn on the valve, the gas flows through the valve into a tube that
is then attached to a safety control valve. The safety control valve doesn't
allow gas to flow through to the burner unless there is an ignition source
available. The ignition may be provided by a standing pilot light flame
or by an electric igniter. When the gas flows and ignites, the flame stays
lit until the thermostat senses the proper temperature and shuts off the
gas flow.
With
a digitally controlled system, there's no need for a mechanical gas valve.
Instead, the digital circuitry sends the signal straight to the safety
valve. Then, if the electric igniter is working properly, the safety valve
opens and sends the gas to the burner, and the hot igniter ignites it.
The digital system uses a small electronic sensor inside the oven to sense
the temperature. When the set temperature is reached, the circuitry sends
a signal to turn the safety valve off, which stops the flow of gas. When
the oven temperature cools slightly, the sensor again sends a signal to
the circuit board, which re-lights the burner.
|
| The
area beneath the cooktop |
| Many
cooktops that have non-sealed gas burners let you raise the cooktop for
cleaning and service. Many manufacturers often also place the model and
serial number tag for the appliance beneath the cooktop. In addition, the
individual burner gas valves and ignition components may be located here. |
| The
interior of the oven |
| The
rack inside the oven holds the food to be cooked. The interior light bulb,
the thermostat sensor, and, in some units the broiler components, are also
located here. |
| The
area behind the broiler drawer |
| This
is where the safety valve, spark igniter, fuse, and other components are
often located. |
| The
back of the unit |
| Much
of the wiring for a gas range/oven is located on the back of the appliance.
The steel panels that cover the wiring protect both you and the wiring.
Other components--such as relays, self-cleaning switches, transformers,
and terminal blocks--are also behind the protective back panels.
Thanks to Repairclinic.com for this How Things Work: Range / Stove / Oven |
