How to fix an old oven
Salvage your dinner with a quick trip to the hardware store & these tips
Some perverse rule of fate dictates that your electric oven will only fail when there’s a sweaty, half-cooked turkey in its belly. Fortunately, there are a few diagnostic steps — effective on almost all makes and models rusticating in the cottage kitchen — that might salvage your dinner with only a quick trip to the hardware store. These tasks are simple, but do require a basic knowledge of electricity. They also require the use of a multimeter, a simple electrical diagnostic tool. If you do not already own a multimeter and you have no idea what this symbol means — Ω (it stands for “ohm,” a unit of electrical resistance) — then fire up the barbecue and call Electra, the appliance repair lady.
Warm, but not so hot
If your oven seems to work, but is far too hot or too cool, there are a couple of tricks you can try. Look inside the oven and find the thermostat bulb and capillary tube, the little dangly thing often on the rear or side wall that senses your oven’s temperature. These can get bumped off their mounting brackets, causing incorrect temperature readings that can misdirect your oven. Reseat the thermostat bulb in its holder and test the oven.
Many electric ovens have two elements, a bake element on the bottom and a broil element on top. Older models use both for the preheat cycle, then switch back to the bake element when the oven is up to temp. If one of these elements is faulty, it might explain why your oven seems to warm up, yet doesn’t cook the turkey evenly or fully.
To test for problems, unplug the range, remove mounting screws (if present) from the rear of the oven cavity, then gently pull out one element to expose its supply wires. Disconnect the element and remove it. (If you see holes, breaks, or bumps, it’s probably kaput.) Set your multimeter on RX1, a setting that measures resistance in ohms, and touch a probe to each of the element’s terminals (fig. A). The meter gauge should move to indicate continuity (a bit of resistance is normal). If it doesn’t move, it means you have an open circuit and a faulty element. Finally, test for ground by touching one probe to an element terminal and the other to the insulating sleeve on the other terminal (fig. B). If your meter shows continuity, the element is shorted and shot. Test the other element this way and replace both with ones of the same wattage if they fail any test. (Stores like Canadian Tire carry universal replacement elements for $25.)
No power, no glory
If your oven and burner elements are dead, the cause could be any number of serious internal faults within your range – requiring the services of a licensed repair maven – or as simple as electricity not making it to the kitchen. The former scenario is most likely, but it’s worth ruling out a lack of power before you call for high-priced help. First, make sure the hydro hasn’t gone out. Next, check the fuses or breakers in your electrical panel. Some ranges also have built-in fuses or breakers, often behind the stove’s display panel. If the fuses are fine but the oven stays dead, test the stove receptacle, or plug-in on the wall.
With your multimeter set in the 240 VAC range, you should get a reading of 220–240 VAC between the two middle slots of your stove receptacle and a reading of 110–120 VAC between the top slot (the neutral) and either of the two middle slots. If there’s no power and your fuses or breaker haven’t blown, you need a new receptacle, which you can replace, or there’s a live wire in your wall — call an electrician.
If power is present, test the power cord next. With the stove unplugged, remove the cover plate on the back and disconnect the three power-cord wires from the stove’s terminal block, a plastic box that distributes incoming power. With your multimeter set on RX1, touch a probe to one prong on the power-cord plug, then touch the other probe to each of the three wires in turn (fig. C). There should be continuity with one of the wire ends. Repeat this test with the other two prongs and make sure each has continuity with a different wire. If the cord is good, your troubles are inside the oven, possibly with the terminal block itself, which is bad news. If the cord fails any of these tests (which it rarely does) you can simply replace it.
Beyond these simple diagnoses, there is a host of horrible things that could be wrong, from a frozen thermostat switch to a major short circuit. Not only are these problems harder to diagnose, but the fix may require model-specific parts. The bottom line is that dinner, for tonight, is ruined. At least you can tell your guests that you tried your best.
This article was originally published on February 12, 2006