A new Ericsson free-liquid-piston engine (FLPEE) configuration was previously presented. This consists of a U-shaped tube filled with water in its lower part, and whose two branches are closed by cylinder heads fitted with valves. The space between the surface of the liquid and the cylinder head of one of the branches constitutes the compression space, while this same space constitutes the expansion space in the other branch. The configuration studied operates in an open cycle. This system is able to produce compressed air which can be expanded in an external device to produce mechanical energy. This FLPEE is thought to be suited for the conversion of thermal energy such as solar energy, biomass or flue gases. In this communication, the experimental bench is presented in detail. In particular, the valve control system of the compression and expansion spaces, the various sensors and the data acquisition system are described. Various experimental results are presented, notably in the form of (p, V) indicator diagrams of the compression and expansion cylinders. These results confirm what the theoretical modelling had predicted, namely that it is possible to obtain a set of values of the operational parameters of the system leading to a stable operation of the free-piston system.