Temperature control is very important in wire rod production. A short rapid water cooling equipment for wire rod has been studied in pilot-plant trials at MEFOS. The equipment is mainly a water filled tube, fed by a housing with a circumferential nozzle. Cooling experiments were done with 25 mm C-Mn steel bars rolled to 19 mm bars. The cooling equipment diameters were 25 mm and 30 mm. The decrease in temperature was measured as well as feeding water pressure in the housing and water pressure in the cooling tube. The heating temperature, rolling speed, cooling tube length and water pressure were changed for the 25 mm equipment. Temperature difference between head and tail ends of the bar was also studied for the 25 mm equipment. Nozzle gap, tube length and water pressure were changed for the 30 mm equipment. A statistical analysis of the cooling results for the 25 mm equipment showed that the cooling was dependent on the water pressure, rolling speed and the furnace temperature. A change in water pressure from 1.4 to 22.8 bar increased the cooling 90 °C. The temperature difference between the ends of the bar was only influenced by the initial temperature difference and the bar temperature. The results from experiments with 30 mm equipment showed no effect on nozzle gap and tube length. The cooling effect of 30 mm equipment at pressures from 2.5 to 5 bar is similar to 25 mm equipment. The variation of cooling with pressure is higher compared with 25 mm equipment. The water consumption in a 30 mm equipment is twice the consumption in a 25 mm equipment at the same pressure.