Lars Josefsson | Marine Steam Boilers Alarm and Trip Functions

Marine Steam Boilers' Alarm and Trip

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The most important alarm and trip functions on marine boilers
Function Audible and visual Action
Low water level Alarm  
Low Low water level * Alarm Burner stop
High water level Alarm  
High High water level Alarm Feedwater pump stop
Low steam pressure Alarm  (overridden on slave boiler?)  
High steam pressure Alarm Burner stop
Low feedwater pressure Alarm Stand-by pump start
Low fuel oil pressure Alarm Stand-by pump start
Low fuel oil temperature Alarm  
High fuel oil temperature Alarm  
Low combustion air pressure Alarm Burner stop
Low atomizing steam pressure Alarm Burner stop
Flame failure ** Alarm  (overridden during light-up) Burner stop
Burner not in firing position Alarm Burner stop


* This function requires two independent level switches connected electrically in series. One of the switches may be a limit switch on the level control transmitter's measuring signal.
** This function requires two independent flame detectors and their switches connected electrically in series.
Possibility to distinguish between flame failures occurring during the burner's start-up sequence and flame failures that occur during normal firing would be a great advantage.