Hello, I am currently working on a model for a BTES with 100 BHEs. I have a good mesh and a fine horizontal discretization. the model works fine if I chose a maximum number of iterations of 1 per time step, but if I want to increase the max number of iteration to a higher number, the time stepping gets trapped to a really low time step and after 1000 iterations feflow stops the simulation. my numerical parameters are: error tolerance of 0.1*10-3; maximum errow norm no upwinding initial time-step length of 0.0001 and a max. growth factor of 1.1 Does someone has an idea what else I could change for better results or how to handle this problem? Best regards Felix