J-K-L

L

LAGGING – A light gauge steel covering used over a boiler, usually combined with insulation, to provide a low temperature outer surface.

LEAKAGE – The uncontrolled quantity of fluid which enters or leaves through the enclosure of air or gas passages.

LIBERATION – See Heat Release.

LIMIT CONTROL – A switching device that completes or breaks an electrical circuit at predetermined pressures or temperatures. Also known as an interlock. See interlock.

LINING – The material used on the furnace side of a furnace wall. It is usually of high grade refractory tile or brick or plastic refractory material.

LOAD – The rate of output required; also the weight carried.

LOAD FACTOR – The ratio of the average load in a given period to the maximum load carried during that period.

LOW GAS PRESSURE CONTROL – A control to stop the burner if gas pressure is too low.

LOW OIL TEMPERATURE CONTROL – (Cold Oil Switch) A control to prevent burner operation if the temperature of the oil is too low.

LOW WATER CUTOFF – Safety device that shuts off the boiler/burner in the event of low water, preventing pressure vessel failure.

LUG – Any projection, like an ear, used for supporting or grasping.