Boilers Alarm and Trip Functions

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.

©2009 Lars Josefsson Steamesteem in a computerized world Marine steam boilers today and yesterday.
Steamesteem means that I like steam boilers and steamships, paddle steamers as well as screw-propelled steamships.