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GPM vs Minimum FPS To Keep Air In Solution
A heating zone's design heat loss is 10Kbtu which requires only 1gpm through 3/4" copper pipe but that would be a velocity of only .73 feet per second, far below what is said to the required minimum of 2fps to keep any air in solution. On a shoulder season day, zone heat loss could be only 3000Kbtu which would mean far less than 1gpm could cover it. But do you overpump to meet the fps requirement? OR if you properly remove most of the air, can you then pump at the best speed to cover the heat loss? And then how do you factor in the larger near-boiler piping, and old 1" gravity risers into the equation?