The water level in a boiler should not go level than a minimum level, which causes overheating to the boiler. Overheating of the boiler causes the boiler walls weak and brittle.
If the air temperature drops too small, the easiest way to avoid overheating harm to the furnace is to stop the burner. That’s the task of the poor water cut-off.
Float Operated Low Water Cut-Offs:
Float operated Low Water Cut-Off (LWCO) is mounted directly to the boiler’s gauge glass tapping.
The water level in the low water cut-off’s chamber will replicate the plant water level. During steaming, as the water level falls in the boiler, the cabinet temperature and the float of the cut-off falls with it.
When the float drop to the boiler’s critical low water cut-off point, the float will trip an electrical switch that operates the burner. The burner instantly stops firing. It will stay off until the water level rises to a safe operating point.
For example, a tube breaks or someone enters a boiler tube that abruptly causes the boiler to lose water. If this happens, the water level will drop to a preset point and the automatic feeder/cut-off combination will immediately reduce the burner’s power, shut it down and protect the boiler from dry-firing. Though the burner is off, the automatic feeder will continue to add water to the boiler in an attempt to restore a safe minimum water level