Steam boiler has a important function to produce steam with the best quality and efficient. Combustion process give heat transfer to water inside water wall tubes then water will be evaporated continuously to generate steam. In the process of steam release, steam boiler needs a certain amount of water surface area. Tolerance of height water level slightly exceeding normal water level should be considered if at any time the increase in load which allow the rise elevation of water level but still within safety limit.
Engineer who design steam boiler should make sure that steam can be produced in calculated area of normal water level and steam can be distributed with the correct velocity. Specific the lowest height of steam which can be generated above normal water level should be determined. The normal water level should be maintained, so supply of feedwater must be maintained, do not be shortage.
If steam boiler is performed with insufficient feedwater or under normal even low water level then steam boiler will has high possibility to explosion and damage. Therefore some actions should be taken such as maintain water level and give good actions if low water level is detected. The actions are turn on the alarm and turn off the operation of steam boiler.