Oven takes an unusually long time to preheat or never reaches the set temperature; no error code displayed.

Safety first: Turn off power at the breaker before inspecting wiring or elements. For gas models, shut off gas supply if removing burners.

• Check both elements (electric): During preheat, look to see if both bake and broil elements glow red at some point. If one never heats, test and replace the failed bake element or broil element.
• Verify power supply: Have an electrician confirm that 240V is present at the range terminal block. A missing leg can cause slow heating.
• Inspect gas flame (gas): The oven burner flame should be blue and even along the burner. Yellow tips or uneven flame indicate clogged ports; clean the burner with a brush and compressed air.
• Control relay: If all hardware checks out but preheat remains slow, the EOC may not be cycling elements correctly. Replacement of the electronic oven control board may be required.

Do not use foil to cover the entire oven bottom; this can block heat circulation and cause poor preheat performance.