The report presents the results obtained during the commissioning the Electron Cooling System (ECS) of the Booster, the first in the chain of three synchrotrons of the NICA accelerator complex. The work was performed with a circulating ion beams 4He1+ and 56Fe14+ at ion injection energy of 3.2 MeV/u. In the first experiment (December 2020) with a circulating 4He1+ ion beam, the effect of reducing the lifetime of the circulating ions was observed when the velocities of the cooling electrons and the cooled ions coincide. In second experiment (September 2021) the effect of electron cooling of 56Fe14+ ion beam was registered both for longitudinal and transverse degrees of freedom using Schottky noise spectrometer and ionization profilometer.