Appliance Repair

Understanding Oven Preheat Cycles

Most residents think “preheat” means “350 means 350.” But as a technician, you know better. In this video, we break down the oven preheat cycle—why it overshoots, dips, and levels out over time. You’ll learn how to track temperature fluctuation using a multimeter with a thermocouple, how to document highs and lows, and how to calculate the real average temp your appliance hits during preheat.
Diagnostic
Hard Skills
Appliances
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Transcript

 So for that, let me explain to you how the oven preheat cycle works. Alright. Let's take for example, an oven in that I wanna set to 350 degrees, just because that's the set temperature that I want, right? I wanna bake something at three 50. So the dotted line, the blue dotted line is the set temperature, and the red line that you're gonna see is the actual temperature with ovens, especially electric ovens, but gas ovens too, with ovens.

What happens is the temperature begins to rise. And then it's gonna overshoot a little bit. Then it drops overshoots and eventually levels out at about 350 degrees. And what happens is those highs and lows, if you average out those values, you can see what the average temperature is after the preheat cycle has completed.

Now, this is gonna require you to have a multimeter with a thermocouple that's inside of the oven cavity. And you have your multimeter, you're looking at it, you have a piece of paper. Also, you're writing down these temperature values, okay? This is exactly how you're gonna do this, right? You're gonna take your, you take your notepad and write down, look at the multimeter and see when the temperature went.

Its highest point. When it dropped, when it went high dropped. You're gonna do this six times, okay? So let me show you on the graph over here. I actually did this with an oven, and I saw 3 70, 3 38, 3 58, 3 42, 3 57, and 3 42. These were the highs and lows that I was able to record on paper, right on a piece of paper after looking at my value on my multimeter.