Leave it unused and obtain qualified assessment. A delayed trip can relate to changing operating stages, but timing alone cannot identify a heater, motor or other component.
What the observation tells you
Repeatedly resetting the supply to wait for another trip creates risk and may erase useful evidence. Do not disable protective devices, substitute a higher-rated fuse or open electrical covers. The installation may also need assessment if its condition is uncertain.
A useful next step
Record the elapsed time, any warning and what else was using the supply. Arrange suitable food storage while the appliance and supply are checked.
Manuals and supporting guidance
Model-specific instructions take priority. These references support the practical principles discussed here; they do not diagnose your appliance.