If you define "high" vacuum as being closer to total vacuum (0 bara), and "low" vacuum as being closer to atmospheric pressure (0 barg), then "low vacuum problem" means that your vacuum pump isn't working correctly or you have a leak somewhere in the system.

It could also be that you are not getting enough cooling capacity to the condenser or the vapor flow rate is too much for the capacity of the condenser.

.........which means that the thermal plant is not operating as economically as it could. A low temperature and high vacuum in the condenser means that more energy can be obtained from the same charge of fuel. This plant isn't going there. So there is considerable incentive to fix it.

Steam condensors provided at the exhaust end of the turbine at kept at vacuume to obtain or extract maximum energy of the steam before its condensation in the condensor. The vacuume in the condensor may have some problem of leakage or vacuume ejectors may not be working nicely or inerts may have accumulated in the condensor in all such problems the level of vacuume is on lower side then expected (say -0.6 in place of -0.85kg/cm2). This condition is not good for turbine efficiency.

Dear Mr. Mukesh0861,

In addition to the above details, the FOULING FACTOR of the CONDENSER also be a reason for Low Vaccuum.

If the tubes are coated with scale, in the Condenser, the HEAT TRANSFER Co-Efficient for heat transfer is affected and condensing of steam will suffer and cause low vaccuum.

Rajeswari.