By far the most common issue is the igniter below the floor inside your oven is just starting to fail and needs to be ordered and replaced. Oven igniters last about 6-8 years under normal use before they tend to start failing. Flat oven igniters need to draw at least 3.2 amps and round oven igniters need to draw at least 2.4 amps or else they won’t open the gas valve correctly. This could lead to the valve just slightly cracking open, or opening and shutting the valve several times when it should just be holding open; resulting in a gas smell , temperature fluctuations, or no heat at all. It doesn’t matter if the igniter is glowing or not; just because it glows doesn’t mean the igniter is drawing enough power to open the safety valve. The igniter is only about a $50 part and you can replace it yourself if you want to remove the racks inside the oven and then remove the floor to access it. Otherwise it will cost about $150-175 to call someone and replace it for you.
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