Valve for controlling liquids

A valve for controlling liquids, having a piezoelectric unit (3) for actuating a valve member (2), which is axially displaceable in a bore (8) of a valve body (9) and which has at least one control piston (7) and at least one actuating piston (10), wherein the valve member (2) is assigned a valve closing member (13), which cooperates with at least one valve seat (14, 15), provided on the valve body (9), for opening and closing the valve (1) and divides a low-pressure region (16) at system pressure from a high-pressure region (17), and having a hydraulic chamber (11) serving as a tolerance compensation element to compensate for elongation tolerances of the piezoelectric unit (3) and as a hydraulic step-up means, between the control piston (7) and the actuating piston (10), wherein to compensate for leakage losses, a conduit (24, 27), having a filling device (23), that communicates with the high-pressure region (17) is provided, which has a system pressure chamber (24, 26, 26′) that discharges into a gap selected from the group consisting of a gap (25′), surrounding the actuating piston (10) and a gap (25) surrounding the control piston (7).