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Hi it’s Steve from PartSelect. Today we are going to try to determine the causes of
a gas oven not lighting or not heating, remember parts are specific to your model of oven and
the one shown today may not be the right parts for you. To get the right part for your oven
be sure to search partselect.com using your model number, if you need help finding your
model use our model number locator, the link is in the description, gas ovens burn wither
propane or natural gas, most gas ranges currently available use one of three basic gas ignition
systems, a pilot flame, a spark igniter or a hot surface igniter. The last two are referred
to as electronic ignition systems because they use electricity to light the oven burner,
only the pilot ignition system has a natural pilot flame to light the burner, even though
your oven is heated by gas, the controls are electric, and your range must be powered to
work properly. Whenever you have an electrical appliance it will not turn on the first thing
to check is the power supply, make sure everything is plugged in and that the cord is in proper
working condition.
The next thing to check will be your gas supply, make sure that any manually operated supply
valves are in the on position, and that there are no kinks in the gas line, this will also
include checking to ensure that there is no obstruction in the burner tube connecting
the orifice of your gas valve to the burner, this could include cobwebs, soot or cooking
debris.
If you still have no gas supply to the ranger oven then you should contact a qualified gas
service technician, if the surface burners of your range are functioning properly then
you can assume that the gas supply is okay. If the surface burners of a range are a spark
ignition type, the oven will typically have an electronic ignition system and therefore
should not have a power light, please remember that just because the surface burners might
light by a spark that doesn’t necessarily mean the oven uses a spark type ignition system
too. Hot surface igniters or glow coils are the most common source of oven ignition on
ranges that have spark igniters for the surface burners.
What happens with a glow bar ignition system set the thermostat or electronic control closes
the switch to supply line voltage power to the oven igniter and gas valve circuit which
are connected in series. This current flows through this circuit igniter heats up and
begins to glow. When the igniter gets hotter it draws more current and when the current
level reaches a specific amount a bi-metal inside the oven safety valve will activate
and allow gas to flow and the glowing hot igniter will ignite it.
Power must continually flow through the igniter and oven gas valve for gas to be released
into the oven burner to create a flame. Once the set temperature is achieved the control
stops all power to the ignition circuit, which causes the igniter to dim and the oven gas
valve to close stopping any burner flame. Cycling on and off continues to maintain specific
temperature the control is set for, many ovens use a single oven burner and then in this
case they only have a single gas valve and igniter, same burner is used for both bake
and broil functions. On the high end models with separate bake and broil burners there
will be an igniter for each burner, and they also use a dual gas valve instead of a separate
valve for each burner, on models utilizing a dual gas valve the internal construction
of the valve allows the bake and broil functions to operate independently of each other.
Each side of the dual gas valve should be looked at as two separate single gas valves,
as long as the igniter is being powered the control system or thermostat is operating
fine, and it should only take about a minute for the oven igniter to reach the resistance
that allows the proper current for the gas valve to open, and the correct temperature
for the gas to ignite. The igniter although glowing may not be allowing the proper amount
of current flow through it for the bi-metal and the oven valve to open, it is also possible
for the oven burner to light and cycle a few times and then fail to ignite anymore, or
to take a very long time to ignite and then therefore fail to maintain the select temperature.
Proper testing of the igniter requires an ammeter to check for adequate current flow
through the circuit to the oven valve, another part that may malfunction is a safety valve
itself. If the igniter check outs okay, remove power from the range, remove the wires from
the valve and perform a continuity test with an ohmmeter. A working safety valve should
read about 2-5 ohms. If open replace the valve, now that you have a better idea of your problem
and can identify what the solution could and what if any parts you need to repair or replace
go to partselect.com, there you can order your parts and find more information about
your specific repair.