51.What is partial loss of flame?

In a wall fired boiler when a flame scanner sense no flame, the respective burner shut-off valves are demanded to close. If they are failed to close after 10 sec. it is announced as Partial Flame loss.

If the number burners are less than a number which can cause unsafe condition, MFT will be initiated. Sometimes a load factor less then 75% is also ANDed for MFT.

Conservatively some plants are initiating MFT for Partial Flame loss irrespective of any condition of the boiler.