  Two-species condensing zero range processes (ZRPs) are interacting particle
systems with two species of particles and zero range interaction exhibiting
phase separation outside a domain of sub-critical densities. We prove the
hydrodynamic limit of nearest neighbour mean zero two-species condensing zero
range processes with bounded local jump rate for sub-critical initial profiles,
i.e., for initial profiles whose image is contained in the region of
sub-critical densities. The proof is based on H. T. Yau's relative entropy
method, which relies on the existence of sufficiently regular solutions to the
hydrodynamic equation. In the particular case of the species-blind ZRP, we
prove that the solutions of the hydrodynamic equation exist globally in time
and thus the hydrodynamic limit is valid for all times.
