One reminds that with the automatic option, according the temperature difference seen on all nodes of the domain at the previous time step (time step n), SYRTHES estimates the value of the following time step (ie time step n+1) so that the temperature do not change more than the specified temperature difference.
When reaching convergence (or a temporary flat evolution during a transient)
the temperature field may not change bewteen time step n and n+1. If not limiting
the time step, then time step n+2 could be extremely large and prevent the capture
of evolutions to come. To prevent this to happen, users are asked to
set the maximum value (in seconds) for time step.