| Yes, excellent physical description, but you didn't give us any running data ... as the others have suggested, what is the pressure on the boiler when cold, and again when hot ... and tell us the temperature that you took these pressure readings.
If your city water pressure is less than the pressure in the boiler, I'd sure ask them why I'm paying a water bill ... water will just 'piddle' out of a tap at 15-20 PSI ...
One clarification I'd like to make though ... the more zones that are open, the lower the pressure drop ... or 'head' ... just like resistors in parallel (hey Xiphias, there's the electrical analogy again!) the total resistance (head) is always lower than the lowest one ...
It's probably not 'linear' as resistors would be, but the basic premise is true.
Let's say there's two zones, with valves... one zone is open, lets say 5 feet of head. Second zone opens, also 5 feet of head ... total head would be somewhere around half ... or 2.5 feet ... __________________
The following statement is true.
The previous statement is false. |