On systems where return temperature is above 200°F at sea level, NPSH of pump is important to avoid cavitation problems.
Available NPSH
Available NPSH must be equal to or greater than the pump's required NPSH. Value of the pump's required NPSH is obtained from the pump performance curve. If NPSH required exceeds Available NPSH, either the temperature of the condensate must be lowered or the tank be elevated to a height where Available NPSH and tank elevation meets or exceeds required NPSH.
Pressurizing a tank has no effect on the calculated Available NPSH if the corresponding temperature also rises. In other words, for any water temperature input of 212°F (boiling point) or greater, the feet of head will always be zero (0) regardless of elevation.
Pressurizing a tank has no effect on the calculated Available NPSH if the corresponding temperature also rises. In other words, for any water temperature input of 212°F (boiling point) or greater, the feet of head will always be zero (0) regardless of elevation.