1. Temperature rises, but fails to reach set requirements:
1) Check the thermostat. This includes the thermostat's heating output status, output power ratio setting (if the thermostat has this function), temperature compensation setting, over-temperature setting action and set value, and PID parameters (refer to factory settings).
2) Check if the heating elements and heating control circuit are functioning correctly. Some ovens use multiple heating elements; check if each group is working properly. This can be done by measuring the current in each phase of each heating element with a clamp meter, or by disconnecting the heating elements and measuring their resistance.
2. Temperature does not rise, no heating:
1) Check the thermostat status indicator and settings.
2) Check the heating elements and control circuit, including whether the AC contactor is engaged correctly, whether the heating circuit breaker is open, and whether the intermediate relay is functioning correctly.