Oven Not Heating? Bake Elements, Igniters & Thermostats

Gas vs. Electric Oven Heating Architectures

When an oven refuses to heat, diagnostics depend on whether it uses 240-volt electric power or natural gas. While both types rely on an electronic board or thermostat, their heating mechanisms differ substantially.

1. Defective Gas Glow-Bar Igniter (Most Common Gas Failure)

In modern gas ovens, ignition is controlled by an electric glow-bar igniter wired in series with a bi-metal gas safety valve. When you set the oven to bake, current flows through the igniter, heating it to over 2,000°F until it glows bright white-hot.

The Amperage Draw Requirement: The gas safety valve will not open until the igniter draws between 3.2 and 3.6 amps. Over years of thermal stress, the igniter's resistance rises. It may still glow bright orange, fooling homeowners into thinking it works, but lacking the amperage necessary to open the valve. If your igniter glows for more than 90 seconds without lighting the burner, it has weakened and requires replacement.

2. Blown Electric Bake or Broil Element

Electric ovens utilize heavy-gauge nickel-chromium resistance wire encased in an insulated metal sheath. These elements cycle on and off under 240 volts of electricity.

Visual and Meter Testing: With the circuit breaker turned off, examine the bottom element. Common signs of failure include white ash blisters, bulges, or complete burnout fractures. If no physical damage is visible, disconnect the wiring spades and test across the terminals with a digital multimeter. A reading of 15 to 45 ohms confirms good continuity; an infinite resistance reading (open circuit) means the element has burnt open internally.

3. Temperature Sensor Probe Calibration Drift

The oven sensor (a thin metal rod protruding into the upper rear corner of the oven cavity) is a Resistance Temperature Detector (RTD). As oven temperature rises, the sensor's electrical resistance increases predictably.

Resistance Standard: At room temperature (70°F), a standard RTD sensor must measure approximately 1,080 to 1,100 ohms. Grease buildup, bent wiring, or internal sensor degradation can shift this baseline above 1,200 ohms. The control board then assumes the oven is hot and terminates heating prematurely.

4. Relay Failure on the Main Electronic Control Board

The electronic control board houses heavy-duty miniature relays that send 240 volts to electric elements or 120 volts to gas ignition circuits. If a relay contact welds shut or burns open from arcing, touchpad inputs are accepted. However, the board fails to deliver power to the heating components.

If your home experienced power fluctuations or an electrical spike, consult our guide on appliances tripping circuit breakers to isolate main board shorts.

Troubleshooting Decision Matrix

We offer expert diagnostics on wall ovens, slide-in ranges, and cooktops. Visit our dedicated Santa Clara oven repair page or return to our homepage to schedule priority service.