Contrarily to previous synthesis work performed on a laboratory-scale, this paper investigates an automated hydrothermal process to prepare pilot-scale Co2Mn1.5Fe2.1Zn0.4O8 for NTC (negative temperature coefficient) thermistors. The influence of the hydrothermal temperature and time on the material properties was investigated in detail. The thermistors were fabricated with high-quality morphology samples and their electrical properties were measured. The resistance values at 25 degrees C and 50 degrees C were tested to obtain the B constant of the device. The electrical parameters measured for the 150 degrees C-9h thermistor are: B-25/50 = 3895 K and rho(25) = 10.314 k Omega cm. The maximum drift rate of the device is 0.26%, which is much lower than the one measured for previously reported thermistors. The investigated devices exhibit a uniform particle size and outstanding and stable performances. This work lays good foundations for future engineering applications of thermistors.