Abstract: Since the unit No.2 of a power plant was put into production, the vacuum of its condenser was lower at all time. It was found out by complete inspection for the shaft gland that the steam admission and steam return system of the low pressure shaft gland of the bearing shell No.4 and No.6 were connected inversely. After the tubes reconnected conversely, the vacuum of the condenser was reached the designed value; the coal consumption was reduced, and remarkable economical benefit was obtained.

Key words: condenser vacuum, shaft gland system, steam admission of shaft gland, returning steam of shaft gland