Document emR5m7JnD3EaZ4a7mZRjdYDVM

The pressure head for the main system is produced by the difference in weight of the 205 deg. water in the flow risers and the 180 deg. water in the return risers, the two risers being 3 ft. 6 in. high. 190 10 15 Z0 Z5 30 35 40 Hcat Convlyco Houe in woo B. T. U. Tnt DirrtBtNCt in TcnPteATuet or Tnt Watcb in Tnt- Flov ano Cctoen Ciacm Ocjno tO ?. Fic. 6. Friction Heads, in Small Pipes and Elbows, for a 20 deg. Temperature Difference of the Water in the Flow and Return Lines ''The weight of 180 deg. water is 60.58, and that of 205 deg. water is 60:00 lb. per cubic foot. The difference in the weights of the two columns of water is 3H x 0.58, or 2.03 lb. 191