The E.S.P is not a wrong term in the trade, as the name implies; it is the pressure drop through ductwork (supply and return) only, and doesn't include pressure drop through unit components (heating coils, cooling coils, sometimes filters...etc.).
In other word, E.S.P. is the sum of the static...
As far as I am concerned, Maximum turndown ration is the ratio between the full load output of for example, a burner of a boiler or a furance, and its lowest available part load output. Typical values can vary from 1:2 turndown ratio up to 1:8 depending on the size of the boiler and its inherent...
