1.Open the water draining valve of the water level indicator to make steam communicating pipe, water communicating pipe and water level indicator flushed by steam and water at the same time.

2.Close the water communicating valve of water level indicator to make the steam communicating pipe and water level indicator flushed by steam.

3.Open the water communicating valve of water level indicator and close the steam communicating pipe flushed by water.

4.Open the steam communicating valve and close the water draining valve, the flushing work is finished and the normal operation of water level indicator is recovered.