Two vertical central heating pipes are connected by a h

Two vertical central heating pipes are connected by a horizontal section on which a valve with a diameter of d = 0.2 m is installed. The water temperature in the right vertical pipe is tp = 800 ° C, and in the left vertical pipe is t = 200 ° C. Find the differential pressure on the valve on the right and left. The height of the water in the vertical pipes h = 20m above the level of the horizontal pipe.