Dear Experts,

What will happen if the dearator <b>[sic]</b> pressure of the running plant reduces to zero?

 

Worst case, your boiler feed pump inlet pressure gets too low and you experience cavitation. However, one would hope the plant was designed with enough head (usually DA is on the roof).

For a DA to "work" the condensate needs to be at (or damn close) to saturation temperature.

Some DA are designed to work at lower pressures...some designed to work at higher. Look at the plants original heat balance.