Vacuum Install:

Vacuum-rated condensate meters are used for metering on the suction side of a vacuum pump. A thermostatic air valve is recommended as shown.

The vacuum installation is used where condensate is brought back to the power plant through a common return line. In this installation, the master trap isolates the heating system from the vacuum. A reliable, uniform flowing trap such as a float and thermostatic unit is recommended.

If the individual traps are reliable enough to prevent steam leakage into the return line, the master trap may be omitted and the meter installed with an air bypass.

The air bypass should be used whenever air may enter the system. Care in vertical positioning is required to avoid condensate flowing through the air bypass. Vacuum pump controls should permit continuous operation of the vacuum pump in order to ensure drainage of condensate from the meter.

An optional vacuum receiver following the meter also levels out flow conditions.