We’ve all been there: 12 minutes ’til Oprah comes on– just enough time to bake a frozen pizza. So you turn on the oven and… no heat! Oh my, what to do? Where to start?
In this pearl of appliantological wisdom, I’ll explain the basic troubleshooting strategy for figuring out what’s wrong when your oven won’t heat up. Specifics will vary from model to model but those details are trivial. In the words of our beloved emperor waging democracy around the globe to protect truth, justice, and the Ameedican Way here in der Fazzahland, the key thing is the, uh, strategery.
Right then. Let us begin by opening our hymnals to the 6th Law of Prophecy: start troubleshooting right at the problem. That means right at the thing that ain’t doin’ it’s thang. In this case, that means the bake element.
We’ll start with a visual inspection. For this part of the testing, kill power to the oven. That means to turn off the circuit breaker. If you don’t know what I just said, stop reading now and call a professional appliantologist. Inspect the element with a flashlight, look for obvious burned spots or separations.
If the element looks good, then we progress to basic electrical measurements (hint: that’s an illustrative link put there for your edumucation– read it now). Y’see, Hoss, incredibly, the element can look fine from the outside (and usually does) but the inner core, the part that electricity flows through and gets really hot, can be electrically open.
So, we’ll start with a simple resistance measurement of the bake heating element. To do this, you have kill power to the oven and then remove the visible and obvious element retaining screws. Then remove at least one wire from the element; you can, of course, remove the entire element from the oven, as shown in the picture (click for larger view). You’ll be making the measurements with your probes on the element’s terminals.
Measure the resistance with your meter; anything less than 50 ohms is good. If you’re seeing a high resistance reading, like something in the thousands of ohms (denoted with the “K” on most meters) then, ding-ding-ding, you just found the problem– come git you a new element.
If the element tests good, then it’s time to graduate to live tests. That means voltage on the circuit, fire in the hole, fry yo’ ace if’n you ain’t careful. If you don’t know how to safely make live voltage measurements, then stop reading right now and call a professional appliantologist. You’ll also need the wiring or schematic diagram of the oven– these are usually hidden inside the control panel compartment, some disassembly required. Make sure you’ve killed power to the oven before going any further, Homer.
Before we get into the actual live test, it would helpful for you to know how the bake element works so you’ll have some insight into how the live test is done. A bake element operates at 240vac, 120vac is supplied to each side of the heating element. One side is tied more or less directly to L1 or L2 (both of which are tied to 120vac)– see your model-specific wiring diagram, I’m just ‘splaining the strategery here.
The other side of the heating element is connected to the electronic range control either directly or through some intermediary controls. (Antique, RV, or off-grid ranges may not have an ERC but rather a mechanical thermostat. Ahh, those were the days…)
Now, here’s where the real strategery comes in. The basic idea is that when the bake element is turned on, BOTH sides of that element should get 120vac (remember, the element is supposed to have 240vac to heat up properly). So we’re going to split the problem in half by seeing which side of the bake element power circuit isn’t coughing up its 120vac. Then we shall deal harshly with its insolence.
- kill power to the oven (which you already did earlier, right? );
- disconnect one wire from the bake element and then secure it so it doesn’t touch anything else
- clip the common side of your meter to any known ground point, like an unpainted metal surface in the oven;
- re-apply power to the oven;
- measure voltage at both of the element power wire leads;
- the one that isn’t giving you 120vac is the circuit you need to troubleshoot; you can ignore the other side.
See, you just cut the problem in half! Now kill power to the oven again and focus your keen, Vulcan-like squinties on the wiring diagram and locate your problem circuit. Then identify the next component in line between the end of the heating element wire with the missing voltage and wherever it ends up, be it the circuit board or one of the power lugs on the terminal block in the back of the oven. The rest is trivial. Continue applying this essential kata until you find the missing voltage in that circuit.
Ahh, Grasshoppah, can you snatch these pebbles from my hand? If not, or if you need help with the particulars of your range or oven, come start a new topic in the Kitchen Appliance Repair Forum where we can illumine your path with more sage wisdom.
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