  We show that superfluidity can be used to prevent thermalisation in a
nonlinear Floquet system. Generically, periodic driving boils an interacting
system to a featureless infinite temperature state. Fast driving is a known
strategy to postpone Floquet heating with a large but always finite boiling
time. In contrast, using a nonlinear periodically-driven system on a lattice,
we show the existence of a continuous class of initial states which do not
thermalise at all. This absence of thermalisation is associated to the
existence and persistence of a stable superflow motion.
