Each oven, no matter the manufacturer or model, has an igniter. Gas ovens have a spark igniter, while electric ovens have an electrical igniter. Both enable the heating element to turn on and heat up enough to properly and efficiently preheat the oven. Over time, the igniter will weaken and eventually break. This is generally the problem when your oven doesn’t preheat.
Even if your igniter is working properly, your heating element in an electric oven might be broken. These break after several years and generally show nicks, scratches or visible breaks in the pipe. Once a heating element breaks, it cannot be repaired and needs to be replaced.
Many Viking ovens have a digital control panel that can either be defective or lose its calibration. When this happens, the oven may get stuck in self-clean mode or in a timed cycle and will not preheat or may shut off prematurely.
The thermostat tests the temperature of the oven to keep it at one consistent temperature for the duration of the oven heat cycle. If the thermostat is defective, it might register a temperature that is higher than the actual termperature, preventing the machine from reaching the appropriate temperature.