The isotropic n-component critical dynamics model of Sasvári, Schwabl and Szépfalusy is found to have some general n-independent features. We find that quasi-scaling, important for interpreting experimental thermal conductivity measurements in liquid He4, corresponding to n = 2, also occurs at the “natural boundary”, n = 1. In this simpler case, the critical region for the entropy diffusion is again relatively small and the crossover behavior can be described in terms of a quasi-scaling exponent with a value approximately equal to that found for n = 2.