Outlet pipework of the chucking table is joined with the regulation section. Flowmeters P1-P3 serve for the setting and inspection of the testing overflow. The branch embedded with the induction flowmeter P1 serves for overflows Qn, Qmax. The branches embedded with the floating flowmeters P2, P3 serve for overflows Qt, Qmin. Each branch is embedded with a manual closing valve serving for the selection of the track (Klk K2, K3.1, K3.2), and the regulation armature (RVI, RV2, RV3.1, RV3.2), serving for the presetting of the required testing overflow. Arrangement of the regulation section allows for the verification of the measuring gauges, at which, after the presetting of the required overflows, actuated individual tests immediately one after the other, while presetting of the regulation valve is not necessary (each of the three tested overflows is directed to a different branch). In case that values of two consecutive overflows are covered by the size of the flowmeter P3, water is supplied to the flowmeter directed by the couple of parallel branches embedded with the closing valves K3.l, K3.2 and the regulation valves RV3.1, RV3.2.