Oven heats but does not reach the set temperature or takes excessively long to preheat.

Safety first: Disconnect mains power and allow the oven to cool before testing elements.

Steps to diagnose:

• Use an oven thermometer: Place a reliable oven thermometer in the center of the cavity and compare actual temperature to the set temperature.
• Test each element: Access the terminals of the top, bottom, and convection elements. Measure resistance and compare to typical values or to a known-good element. A significantly higher resistance than normal can indicate a weakened element.
• Visual inspection: Look for hot spots, blisters, or cracks on the element surfaces inside the cavity.
• Replace weak elements: Replace any suspect OBH Nordica-compatible elements (top, bottom, or convection ring) and ensure secure connections.
• Check supply voltage: If all elements are good, have a qualified person verify that the mains voltage matches the rating plate. Low voltage can cause slow heating.
• Test: After replacement, perform another preheat test and verify that the oven reaches and maintains the set temperature.